Search Results

Search found 143 results on 6 pages for 'cryptographic'.

Page 4/6 | < Previous Page | 1 2 3 4 5 6  | Next Page >

  • Characteristics of an Initialization Vector

    - by Jamie Chapman
    I'm by no means a cryptography expert, I have been reading a few questions around Stack Overflow and on Wikipedia but nothing is really 'clear cut' in terms of defining an IV and it's usage. Points I have discovered: An IV is pre-pended to a plaintext message in order to strengthen the encryption The IV is truely random Each message has it's own unique IV Timestamps and cryptographic hashes are sometimes used instead of random values, but these are considered to be insecure as timestamps can be predicted One of the weaknesses of WEP (in 802.11) is the fact that the IV will reset after a specific amount of encryptions, thus repeating the IV I'm sure there are many other points to be made, what have I missed? (or misread!)

    Read the article

  • How are CD Keys generated?

    - by The Rook
    CD Keys are the defacto-standard as an anti-piracy measure. To be honest this strikes me as Security Though Obscurity, although I really have no idea how CD Keys are generated. What is a good (secure) example of CD Key generation? What cryptographic primitive (if any) are they using? Is it a message digest? If so what data would they be hashing? What methods do developers employ to make it difficult for crackers to build their own key generators?

    Read the article

  • Calculating very large exponents in python

    - by miraclesoul
    Dear All, Currently i am simulating my cryptographic scheme to test it. I have developed the code but i am stuck at one point. I am trying to take : g**x where g = 256 bit number x = 256 bit number Python hangs at this point, i have read alot of forums, threads etcc but only come to the conclusion that python hangs, as its hard for it to process such large numbers. any idea how can it be done? any two line piece of code, any library, anything that can be done.(ALSO PLEASE I AM A NEW PYTHON USER AND THIS IS FIRST TIME I DID PROGRAMMING IN IT, SO NO COMPLEX METHODS ...HOPE YOU UNDERSTAND :s)

    Read the article

  • Established javascript solution for secure registration & authentication without SSL

    - by Tomas
    Is there any solution for secure user registration and authentication without SSL? With "secure" I mean safe from passive eavesdropping, not from man-in-the-middle (I'm aware that only SSL with signed certificate will reach this degree of security). The registration (password setup, i.e. exchanging of pre-shared keys) must be also secured without SSL (this will be the hardest part I guess). I prefer established and well tested solution. If possible, I don't want to reinvent the wheel and make up my own cryptographic protocols. Thanks in advance.

    Read the article

  • New Netra SPARC T3 Servers

    - by Ferhat Hatay
    Today at the Mobile World Congress 2011, Oracle announced two new carrier-grade NEBS Level 3- certified servers: Oracle’s Netra SPARC T3-1 rackmount server and Oracle’s Netra SPARC T3-1BA ATCA blade server bringing the performance, scalability and power efficiency of the newest SPARC T3 processor to the communications market.    The Netra SPARC T3-1 server enclosure has a compact 20inch-deep carrier-grade rack-optimized design The new Netra SPARC T3 servers further expand Oracle’s complete portfolio for the communications industry, which includes carrier-grade servers, storage and application software to run operations support systems and service delivery platforms with easy migration capabilities and unmatched investment protection via the binary compatibility guarantee of the Oracle Solaris operating system. With advanced reliability, networking and security features built-in to Oracle Solaris – the most widely deployed carrier-grade OS – the systems announced today are uniquely suited for mission-critical core network infrastructure and service delivery. The world’s first carrier-grade system using the 16-core, 128-thread SPARC T3 processor, the Netra SPARC T3-1 server supports 2x the I/O bandwidth, 2x the memory and is 35 percent faster than the previous generation. With integrated on-chip 10 Gigabit Ethernet, on-chip cryptographic acceleration, and built-in, no-cost Oracle VM Server for SPARC and Oracle Solaris Containers for virtualization, the Netra SPARC T3-1 server is an ideal platform for consolidation, offering 128 virtual systems in a single server. As the next generation Netra SPARC ATCA blade, Netra SPARC T3-1BA ATCA blade server brings the PICMG 3.0 compatibility, NEBS Level 3 Certification, ETSI compliance and the Netra business practices to the customer solution. The Netra SPARC T3-1BA ATCA blade server can be mixed in the Sun Netra CT900 blade chassis with other ATCA UltraSPARC and x86 blades.     The Netra SPARC T3-1BA ATCA blade server   The Netra SPARC T3-1BA ATCA blade server delivers industry-leading scalability, density and cost efficiency with up to 36 SPARC T3 processors (3456 processing threads) in a single rack – a 50 percent increase over the previous generation. The Netra SPARC T3-1BA blade server also offers high-bandwidth and high-capacity I/O, with greater memory capacity to tackle the increasing business demands of the communications industry. For service providers faced with the rapid growth of broadband networks and the dramatic surge in global smartphone adoption, the new Netra SPARC T3 systems deliver continuous availability with massive scalability, tested and certified to run in the harshest conditions. More information Oracle’s Sun Netra Servers Scaling Throughput and Managing TCO with Oracle’s Netra SPARC T3-1 Servers Enabling End-to-End 10 Gigabit Ethernet in Oracle's Sun Netra ATCA Product Family Data Sheet: Netra SPARC T3-1BA ATCA Blade Server Data Sheet: Netra SPARC T3-1 Server Oracle Solaris: The Carrier Grade Operating System

    Read the article

  • eSTEP Newsletter October 2012 now available

    - by uwes
    Dear Partners,We would like to inform you that the October '12 issue of our Newsletter is now available.The issue contains information to the following topics:News from CorpOracle Announces Oracle Solaris 11.1 at Oracle OpenWorld; Oracle Announces Oracle Exadata X3 Database In-Memory Machine; Oracle Enterprise Manager 12c introduces New Tools and Programs for Partners; Oracle Unveils First Industry-Specific Engineered System - the Oracle Networks Applications Platform,;  Oracle Unveils Expanded Oracle Cloud Offerings; Oracle Outlines Plans to Make the Future Java During JavaOne 2012 Strategy Keynote; Some interesting Java Facts and Figures; Oracle Announces MySQL 5.6 Release Candidate Technical Section What's up with LDoms (4 tech articles); Oracle SPARC T4 Systems cut Complexity, cost of Cryptographic Tasks; PeopleSoft Enterprise Financials 9.1; PeopleSoft HCM 9.1 combined online and batch benchmark,; Product Update Bulletin Oracle Solaris Cluster Oct 2012; Sun ZFS Storage 7420; SPARC Product Line Update; SPARC M-series -  New DAT 160 plus EOL of M3000 series; SPARC SuperCluster and SPARC T4 Servers Included in Enterprise Reference Architecture Sizing Tool; Oracle MagazineLearning & EventsRecently delivered Techcasts: An Update after the Oracle Open World, An Update on OVM Server for SPARC; Update to Oracle Database ApplianceReferencesBridgestone Aircraft Tire Reduces Required Disk Capacity by 50% with Virtualized Storage Solution; Fiat Group Automobiles Aligns Operational Decisions with Strategy by Using End-to-End Enterprise Performance Management System; Birkbeck, University of London Develops World-Class Computer Science Facilities While Reducing Costs with Ultrareliable and Scalable Data Infrastructure How toIntroducing Oracle System Assistant; How to Prepare a ZFS Storage Appliance to Serve as a Storage Device; Migrating Oracle Solaris 8 P2V with Oracle Database 10.2 and ASM; White paper on Best Practices for Building a Virtualized SPARC Computing Environment, How to extend the Oracle Solaris Studio IDE with NetBeans Plug-Ins; How I simplified Oracle Database 11g Installation on Oracle Linux 6You find the Newsletter on our portal under eSTEP News ---> Latest Newsletter. You will need to provide your email address and the pin below to get access. Link to the portal is shown below.URL: http://launch.oracle.com/PIN: eSTEP_2011Previous published Newsletters can be found under the Archived Newsletters section and more useful information under the Events, Download and Links tab. Feel free to explore and any feedback is appreciated to help us improve the service and information we deliver.Thanks and best regards,Partner HW Enablement EMEA

    Read the article

  • SSL Certifcate Request s2003 DC CA DNS Name not Avaiable.

    - by Beuy
    I am trying to submit a request for an SSL certificate on a Domain Controller in order to enable LDAP SSL, and having no end of problems. I am following the information provided at http://support.microsoft.com/default.aspx?scid=kb;en-us;321051 & http://adldap.sourceforge.net/wiki/doku.php?id=ldap_over_ssl Steps taken so far: Create Servername.inf with the following information ;----------------- request.inf ----------------- [Version] Signature="$Windows NT$ [NewRequest] Subject = "CN=servername.domain.loc" ; replace with the FQDN of the DC KeySpec = 1 KeyLength = 1024 ; Can be 1024, 2048, 4096, 8192, or 16384. ; Larger key sizes are more secure, but have ; a greater impact on performance. Exportable = TRUE MachineKeySet = TRUE SMIME = False PrivateKeyArchive = FALSE UserProtected = FALSE UseExistingKeySet = FALSE ProviderName = "Microsoft RSA SChannel Cryptographic Provider" ProviderType = 12 RequestType = PKCS10 KeyUsage = 0xa0 [EnhancedKeyUsageExtension] OID=1.3.6.1.5.5.7.3.1 ; this is for Server Authentication ;----------------------------------------------- Create Certificate request by running: certreq -new Servername.inf Servername.req Attempt to submit Certificate request to CA by running: certreq -submit -attrib "CertificateTemplate: DomainController" request.req At which point I get the following error: The DNS name is unavailable and cannot be added to the Subject Alternate Name. 0x8009480f (-2146875377) Trouble shooting steps I have taken so far 1. Modify the Domain Controller Template to supply Subject Name in Request restart Certificate Service, include SAN in Request, same error. 2. Re-installed Certificate Services / IIS / Restarted machine countless times Any help resolving the issue would be greatly appreciated.

    Read the article

  • MS SQL - Problem running SQL Server Agent Job via service account credentials

    - by molecule
    There are 5 steps in this job. First job is an SSIS Package store, second to fifth are file system jobs. We configured all jobs to use Windows Authentication. Under Run As, we specified a user account which was created under SecurityCredentials and SQL Server AgentProxiesSSIS Package execution. The job runs without any problems with this user account. We then proceeded to configure the job to use a service account instead. Service account was specified under SecurityCredentials and SQL Server AgentProxiesSSIS Package Execution. The job fails with this error. Executed as user: domain\serviceaccount. ....00 for 32-bit Copyright (C) Microsoft Corp 1984-2005. All rights reserved. Started: 3:37:57 PM Error: 2010-03-09 15:37:57.95 Code: 0xC0016016 Source: Description: Failed to decrypt protected XML node "DTS:Password" with error 0x8009000B "Key not valid for use in specified state.". You may not be authorized to access this information. This error occurs when there is a cryptographic error. Verify that the correct key is available. End Error Error: 2010-03-09 15:38:01.19 Code: 0xC0047062 Source: Get CONT_VIEW_LADDER in latest 45days OracleFMDatabase [1] Description: System.Data.OracleClient.OracleException: ORA-01005: null password given; logon denied at System.Data.OracleClient.OracleException.Check(OciErrorHandle errorHandle, Int32 rc) at System.Data.OracleClient.OracleInternalConnection.OpenOnLocalTransaction(String userName, String password, String serverName, Boo... The package execution fa... The step failed. Based on some research, I then go into MS Visual Studio and Open the project. I change the property of the package security from "EncryptSensitiveWithUserKey" to "DontSaveSensitive" but i still get the above error. I am new to this so any help will be very much appreciated. Thanks in advance

    Read the article

  • CryptSvc not matched by Windows 7 Firewall rule

    - by theultramage
    I am using Windows Firewall in conjunction with a third-party tool to get notified about new outbound connection attempts (Windows Firewall Notifier or Windows Firewall Control). The way these tools do it is by setting the firewall to deny by default, and to add an auditing policy to log blocked connections into the Security event log. Then they watch the log, and display notification about newly added entries. netsh advfirewall set allprofiles firewallpolicy blockinbound,blockoutbound auditpol /set /subcategory:{0CCE9226-69AE-11D9-BED3-505054503030} /failure:enable With this configuration in place, I now need to craft outbound allow rules for applications and system services. Here is the rule for CryptSvc, the service frequently used for certificate validation and revocation checking: netsh advfirewall firewall add rule name="Windows Cryptographic Services" action=allow enable=yes profile=any program="%SystemRoot%\system32\svchost.exe" service="CryptSvc" dir=out protocol=tcp remoteport=80,443 The problem is, this rule does not work. Unless I change the scope to "all programs and services" (which is really unhealthy), connection denied events like the following will keep appearing in the security log: Event 5157, Microsoft Windows security auditing. The Windows Filtering Platform has blocked a connection. Application Information: Process ID: 1476 (<- svchost.exe with CryptSvc and nothing else) Application Name: \device\harddiskvolume1\windows\system32\svchost.exe Network Information: Direction: Outbound Source Address: 192.168.0.1 Source Port: 49616 Destination Address: 2.16.52.16 Destination Port: 80 Protocol: 6 (<- TCP) To make sure it's CryptSvc, I have let the connection through and reviewed its traffic; I also configured CryptSvc to run in its own svchost instance to make it more obvious: ;sc config CryptSvc type= share sc config CryptSvc type= own So... why is it not matching the firewall rule, and how to fix that?

    Read the article

  • apache2 mysql authentication module and SHA1 encryption

    - by Luca Rossi
    I found myself in a setup on where I need to enable some authentication method using mysql. I already have an user scheme. That user scheme is working like a charm with MD5 password and CRYPT, but when I turn to SHA1sum it says: [Fri Oct 26 00:03:20 2012] [error] Unsupported encryption type: Sha1sum No useful debug informations on log files. This is my setup and some info: debian6 apache and ssl installed packages: root@sistemichiocciola:/etc/apache2/mods-available# dpkg --list | grep apache ii apache2 2.2.16-6+squeeze8 Apache HTTP Server metapackage ii apache2-mpm-prefork 2.2.16-6+squeeze8 Apache HTTP Server - traditional non-threaded model ii apache2-utils 2.2.16-6+squeeze8 utility programs for webservers ii apache2.2-bin 2.2.16-6+squeeze8 Apache HTTP Server common binary files ii apache2.2-common 2.2.16-6+squeeze8 Apache HTTP Server common files ii libapache2-mod-auth-mysql 4.3.9-13+b1 Apache 2 module for MySQL authentication ii libapache2-mod-php5 5.3.3-7+squeeze14 server-side, HTML-embedded scripting language (Apache 2 module) root@sistemichiocciola:/etc/apache2/sites-enabled# dpkg --list | grep ssl ii libssl-dev 0.9.8o-4squeeze13 SSL development libraries, header files and documentation ii libssl0.9.8 0.9.8o-4squeeze13 SSL shared libraries ii openssl 0.9.8o-4squeeze13 Secure Socket Layer (SSL) binary and related cryptographic tools ii openssl-blacklist 0.5-2 list of blacklisted OpenSSL RSA keys ii ssl-cert 1.0.28 simple debconf wrapper for OpenSSL my vhost setup: AuthMySQL On Auth_MySQL_Host localhost Auth_MySQL_User XXX Auth_MySQL_Password YYY Auth_MySQL_DB users AuthName "Sistemi Chiocciola Sezione Informatica" AuthType Basic # require valid-user require group informatica Auth_MySQL_Encryption_Types Crypt Sha1sum AuthBasicAuthoritative Off AuthUserFile /dev/null Auth_MySQL_Password_Table users Auth_MYSQL_username_field email Auth_MYSQL_password_field password AuthMySQL_Empty_Passwords Off AuthMySQL_Group_Table http_groups Auth_MySQL_Group_Field user_group Have I missed a package/configuration or something?

    Read the article

  • Will these optimizations to my Ruby implementation of diff improve performance in a Rails app?

    - by grg-n-sox
    <tl;dr> In source version control diff patch generation, would it be worth it to use the optimizations listed at the very bottom of this writing (see <optimizations>) in my Ruby implementation of diff for making diff patches? </tl;dr> <introduction> I am programming something I have never done before and there might already be tools out there to do the exact thing I am programming but at this point I am having too much fun to care so I am still going to do it from scratch, even if there is a tool for this. So anyways, I am working on a Ruby on Rails app and need a certain feature. Basically I want each entry in a table of mine, let's say for example a table of video games, to have a stored chunk of text that represents a review or something of the sort for that table entry. However, I want this text to be both editable by any registered user and also keep track of different submissions in a version control system. The simplest solution I could think of is just implement a solution that keeps track of the text body and the diff patch history of different versions of the text body as objects in Ruby and then serialize it, preferably in human readable form (so I'll most likely use YAML for this) for editing if needed due to corruption by a software bug or a mistake is made by an admin doing some version editing. So at first I just tried to dive in head first into this feature to find that the problem of generating a diff patch is more difficult that I thought to do efficiently. So I did some research and came across some ideas. Some I have implemented already and some I have not. However, it all pretty much revolves around the longest common subsequence problem, as you would already know if you have already done anything with diff or diff-like features, and optimization the function that solves it. Currently I have it so it truncates the compared versions of the text body from the beginning and end until non-matching lines are found. Then it solves the problem using a comparison matrix, but instead of incrementing the value stored in a cell when it finds a matching line like in most longest common subsequence algorithms I have seen examples of, I increment when I have a non-matching line so as to calculate edit distance instead of longest common subsequence. Although as far as I can tell between the two approaches, they are essentially two sides of the same coin so either could be used to derive an answer. It then back-traces through the comparison matrix and notes when there was an incrementation and in which adjacent cell (West, Northwest, or North) to determine that line's diff entry and assumes all other lines to be unchanged. Normally I would leave it at that, but since this is going into a Rails environment and not just some stand-alone Ruby script, I started getting worried about needing to optimize at least enough so if a spammer that somehow knew how I implemented the version control system and knew my worst case scenario entry still wouldn't be able to hit the server that bad. After some searching and reading of research papers and articles through the internet, I've come across several that seem decent but all seem to have pros and cons and I am having a hard time deciding how well in this situation that the pros and cons balance out. So are the ones listed here worth it? I have listed them with known pros and cons. </introduction> <optimizations> Chop the compared sequences into multiple chucks of subsequences by splitting where lines are unchanged, and then truncating each section of unchanged lines at the beginning and end of each section. Then solve the edit distance of each subsequence. Pro: Changes the time increase as the changed area gets bigger from a quadratic increase to something more similar to a linear increase. Con: Figuring out where to split already seems like you have to solve edit distance except now you don't care how it is changed. Would be fine if this was solvable by a process closer to solving hamming distance but a single insertion would throw this off. Use a cryptographic hash function to both convert all sequence elements into integers and ensure uniqueness. Then solve the edit distance comparing the hash integers instead of the sequence elements themselves. Pro: The operation of comparing two integers is faster than the operation of comparing two strings, so a slight performance gain is received after every comparison, which can be a lot overall. Con: Using a cryptographic hash function takes time to convert all the sequence elements and may end up costing more time to do the conversion that you gain back from the integer comparisons. You could use the built in hash function for a string but that will not guarantee uniqueness. Use lazy evaluation to only calculate the three center-most diagonals of the comparison matrix and then only calculate additional diagonals as needed. And then also use this approach to possibly remove the need on some comparisons to compare all three adjacent cells as desribed here. Pro: Can turn an algorithm that always takes O(n * m) time and make it so only worst case scenario is that time, best case becomes practically linear, and average case is somewhere between the two. Con: It is an algorithm I've only seen implemented in functional programming languages and I am having a difficult time comprehending how to convert this into Ruby based on how it is described at the site linked to above. Make a C module and do the hard work at the native level in C and just make a Ruby wrapper for it so Ruby can make all the calls to it that it needs. Pro: I have to imagine that evaluating something like this in could be a LOT faster. Con: I have no idea how Rails handles apps with ruby code that has C extensions and it hurts the portability of the app. This is an optimization for after the solving of edit distance, but idea is to store additional combined diffs with the ones produced by each version to make a delta-tree data structure with the most recently made diff as the root node of the tree so getting to any version takes worst case time of O(log n) instead of O(n). Pro: Would make going back to an old version a lot faster. Con: It would mean every new commit, the delta-tree would get a new root node that will cost time to reorganize the delta-tree for an operation that will be carried out a lot more often than going back a version, not to mention the unlikelihood it will be an old version. </optimizations> So are these things worth the effort?

    Read the article

  • OpenVPN - Windows 8 to Windows 2008 Server, not connecting

    - by niico
    I have followed this tutorial about setting up an OpenVPN Server on Windows Server - and a client on Windows (in this case Windows 8). The server appears to be running fine - but it is not connecting with this error: Mon Jul 22 19:09:04 2013 Warning: cannot open --log file: C:\Program Files\OpenVPN\log\my-laptop.log: Access is denied. (errno=5) Mon Jul 22 19:09:04 2013 OpenVPN 2.3.2 x86_64-w64-mingw32 [SSL (OpenSSL)] [LZO] [PKCS11] [eurephia] [IPv6] built on Jun 3 2013 Mon Jul 22 19:09:04 2013 MANAGEMENT: TCP Socket listening on [AF_INET]127.0.0.1:25340 Mon Jul 22 19:09:04 2013 Need hold release from management interface, waiting... Mon Jul 22 19:09:05 2013 MANAGEMENT: Client connected from [AF_INET]127.0.0.1:25340 Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'state on' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'log all on' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'hold off' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'hold release' Mon Jul 22 19:09:05 2013 Socket Buffers: R=[65536->65536] S=[65536->65536] Mon Jul 22 19:09:05 2013 UDPv4 link local: [undef] Mon Jul 22 19:09:05 2013 UDPv4 link remote: [AF_INET]66.666.66.666:9999 Mon Jul 22 19:09:05 2013 MANAGEMENT: >STATE:1374494945,WAIT,,, Mon Jul 22 19:10:05 2013 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) Mon Jul 22 19:10:05 2013 TLS Error: TLS handshake failed Mon Jul 22 19:10:05 2013 SIGUSR1[soft,tls-error] received, process restarting Mon Jul 22 19:10:05 2013 MANAGEMENT: >STATE:1374495005,RECONNECTING,tls-error,, Mon Jul 22 19:10:05 2013 Restart pause, 2 second(s) Note I have changed the IP and port no (it uses a non-standard port for security reasons). That port is open on the hardware firewall. The server logs are showing a connection attempt from my client: TLS: Initial packet from [AF_INET]118.68.xx.xx:65011, sid=081af4ed xxxxxxxx Mon Jul 22 14:19:15 2013 118.68.xx.xx:65011 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) How can I problem solve this & find the problem? Thx Update - Client config file: ############################################## # Sample client-side OpenVPN 2.0 config file # # for connecting to multi-client server. # # # # This configuration can be used by multiple # # clients, however each client should have # # its own cert and key files. # # # # On Windows, you might want to rename this # # file so it has a .ovpn extension # ############################################## # Specify that we are a client and that we # will be pulling certain config file directives # from the server. client # Use the same setting as you are using on # the server. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel # if you have more than one. On XP SP2, # you may need to disable the firewall # for the TAP adapter. ;dev-node MyTap # Are we connecting to a TCP or # UDP server? Use the same setting as # on the server. ;proto tcp proto udp # The hostname/IP and port of the server. # You can have multiple remote entries # to load balance between the servers. remote 00.00.00.00 1194 ;remote 00.00.00.00 9999 ;remote my-server-2 1194 # Choose a random host from the remote # list for load-balancing. Otherwise # try hosts in the order specified. ;remote-random # Keep trying indefinitely to resolve the # host name of the OpenVPN server. Very useful # on machines which are not permanently connected # to the internet such as laptops. resolv-retry infinite # Most clients don't need to bind to # a specific local port number. nobind # Downgrade privileges after initialization (non-Windows only) ;user nobody ;group nobody # Try to preserve some state across restarts. persist-key persist-tun # If you are connecting through an # HTTP proxy to reach the actual OpenVPN # server, put the proxy server/IP and # port number here. See the man page # if your proxy server requires # authentication. ;http-proxy-retry # retry on connection failures ;http-proxy [proxy server] [proxy port #] # Wireless networks often produce a lot # of duplicate packets. Set this flag # to silence duplicate packet warnings. ;mute-replay-warnings # SSL/TLS parms. # See the server config file for more # description. It's best to use # a separate .crt/.key file pair # for each client. A single ca # file can be used for all clients. ca "C:\\Program Files\\OpenVPN\\config\\ca.crt" cert "C:\\Program Files\\OpenVPN\\config\\my-laptop.crt" key "C:\\Program Files\\OpenVPN\\config\\my-laptop.key" # Verify server certificate by checking # that the certicate has the nsCertType # field set to "server". This is an # important precaution to protect against # a potential attack discussed here: # http://openvpn.net/howto.html#mitm # # To use this feature, you will need to generate # your server certificates with the nsCertType # field set to "server". The build-key-server # script in the easy-rsa folder will do this. ns-cert-type server # If a tls-auth key is used on the server # then every client must also have the key. ;tls-auth ta.key 1 # Select a cryptographic cipher. # If the cipher option is used on the server # then you must also specify it here. ;cipher x # Enable compression on the VPN link. # Don't enable this unless it is also # enabled in the server config file. comp-lzo # Set log file verbosity. verb 3 # Silence repeating messages ;mute 20 Server config file: ################################################# # Sample OpenVPN 2.0 config file for # # multi-client server. # # # # This file is for the server side # # of a many-clients <-> one-server # # OpenVPN configuration. # # # # OpenVPN also supports # # single-machine <-> single-machine # # configurations (See the Examples page # # on the web site for more info). # # # # This config should work on Windows # # or Linux/BSD systems. Remember on # # Windows to quote pathnames and use # # double backslashes, e.g.: # # "C:\\Program Files\\OpenVPN\\config\\foo.key" # # # # Comments are preceded with '#' or ';' # ################################################# # Which local IP address should OpenVPN # listen on? (optional) ;local 00.00.00.00 # Which TCP/UDP port should OpenVPN listen on? # If you want to run multiple OpenVPN instances # on the same machine, use a different port # number for each one. You will need to # open up this port on your firewall. std 1194 port 1194 # TCP or UDP server? ;proto tcp proto udp # "dev tun" will create a routed IP tunnel, # "dev tap" will create an ethernet tunnel. # Use "dev tap0" if you are ethernet bridging # and have precreated a tap0 virtual interface # and bridged it with your ethernet interface. # If you want to control access policies # over the VPN, you must create firewall # rules for the the TUN/TAP interface. # On non-Windows systems, you can give # an explicit unit number, such as tun0. # On Windows, use "dev-node" for this. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel if you # have more than one. On XP SP2 or higher, # you may need to selectively disable the # Windows firewall for the TAP adapter. # Non-Windows systems usually don't need this. ;dev-node MyTap # SSL/TLS root certificate (ca), certificate # (cert), and private key (key). Each client # and the server must have their own cert and # key file. The server and all clients will # use the same ca file. # # See the "easy-rsa" directory for a series # of scripts for generating RSA certificates # and private keys. Remember to use # a unique Common Name for the server # and each of the client certificates. # # Any X509 key management system can be used. # OpenVPN can also use a PKCS #12 formatted key file # (see "pkcs12" directive in man page). ca "C:\\Program Files\\OpenVPN\\config\\ca.crt" cert "C:\\Program Files\\OpenVPN\\config\\server.crt" key "C:\\Program Files\\OpenVPN\\config\\server.key" # Diffie hellman parameters. # Generate your own with: # openssl dhparam -out dh1024.pem 1024 # Substitute 2048 for 1024 if you are using # 2048 bit keys. dh "C:\\Program Files\\OpenVPN\\config\\dh2048.pem" # Configure server mode and supply a VPN subnet # for OpenVPN to draw client addresses from. # The server will take 10.8.0.1 for itself, # the rest will be made available to clients. # Each client will be able to reach the server # on 10.8.0.1. Comment this line out if you are # ethernet bridging. See the man page for more info. server 10.8.0.0 255.255.255.0 # Maintain a record of client <-> virtual IP address # associations in this file. If OpenVPN goes down or # is restarted, reconnecting clients can be assigned # the same virtual IP address from the pool that was # previously assigned. ifconfig-pool-persist ipp.txt # Configure server mode for ethernet bridging. # You must first use your OS's bridging capability # to bridge the TAP interface with the ethernet # NIC interface. Then you must manually set the # IP/netmask on the bridge interface, here we # assume 10.8.0.4/255.255.255.0. Finally we # must set aside an IP range in this subnet # (start=10.8.0.50 end=10.8.0.100) to allocate # to connecting clients. Leave this line commented # out unless you are ethernet bridging. ;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100 # Configure server mode for ethernet bridging # using a DHCP-proxy, where clients talk # to the OpenVPN server-side DHCP server # to receive their IP address allocation # and DNS server addresses. You must first use # your OS's bridging capability to bridge the TAP # interface with the ethernet NIC interface. # Note: this mode only works on clients (such as # Windows), where the client-side TAP adapter is # bound to a DHCP client. ;server-bridge # Push routes to the client to allow it # to reach other private subnets behind # the server. Remember that these # private subnets will also need # to know to route the OpenVPN client # address pool (10.8.0.0/255.255.255.0) # back to the OpenVPN server. ;push "route 192.168.10.0 255.255.255.0" ;push "route 192.168.20.0 255.255.255.0" # To assign specific IP addresses to specific # clients or if a connecting client has a private # subnet behind it that should also have VPN access, # use the subdirectory "ccd" for client-specific # configuration files (see man page for more info). # EXAMPLE: Suppose the client # having the certificate common name "Thelonious" # also has a small subnet behind his connecting # machine, such as 192.168.40.128/255.255.255.248. # First, uncomment out these lines: ;client-config-dir ccd ;route 192.168.40.128 255.255.255.248 # Then create a file ccd/Thelonious with this line: # iroute 192.168.40.128 255.255.255.248 # This will allow Thelonious' private subnet to # access the VPN. This example will only work # if you are routing, not bridging, i.e. you are # using "dev tun" and "server" directives. # EXAMPLE: Suppose you want to give # Thelonious a fixed VPN IP address of 10.9.0.1. # First uncomment out these lines: ;client-config-dir ccd ;route 10.9.0.0 255.255.255.252 # Then add this line to ccd/Thelonious: # ifconfig-push 10.9.0.1 10.9.0.2 # Suppose that you want to enable different # firewall access policies for different groups # of clients. There are two methods: # (1) Run multiple OpenVPN daemons, one for each # group, and firewall the TUN/TAP interface # for each group/daemon appropriately. # (2) (Advanced) Create a script to dynamically # modify the firewall in response to access # from different clients. See man # page for more info on learn-address script. ;learn-address ./script # If enabled, this directive will configure # all clients to redirect their default # network gateway through the VPN, causing # all IP traffic such as web browsing and # and DNS lookups to go through the VPN # (The OpenVPN server machine may need to NAT # or bridge the TUN/TAP interface to the internet # in order for this to work properly). ;push "redirect-gateway def1 bypass-dhcp" # Certain Windows-specific network settings # can be pushed to clients, such as DNS # or WINS server addresses. CAVEAT: # http://openvpn.net/faq.html#dhcpcaveats # The addresses below refer to the public # DNS servers provided by opendns.com. ;push "dhcp-option DNS 208.67.222.222" ;push "dhcp-option DNS 208.67.220.220" # Uncomment this directive to allow differenta # clients to be able to "see" each other. # By default, clients will only see the server. # To force clients to only see the server, you # will also need to appropriately firewall the # server's TUN/TAP interface. ;client-to-client # Uncomment this directive if multiple clients # might connect with the same certificate/key # files or common names. This is recommended # only for testing purposes. For production use, # each client should have its own certificate/key # pair. # # IF YOU HAVE NOT GENERATED INDIVIDUAL # CERTIFICATE/KEY PAIRS FOR EACH CLIENT, # EACH HAVING ITS OWN UNIQUE "COMMON NAME", # UNCOMMENT THIS LINE OUT. ;duplicate-cn # The keepalive directive causes ping-like # messages to be sent back and forth over # the link so that each side knows when # the other side has gone down. # Ping every 10 seconds, assume that remote # peer is down if no ping received during # a 120 second time period. keepalive 10 120 # For extra security beyond that provided # by SSL/TLS, create an "HMAC firewall" # to help block DoS attacks and UDP port flooding. # # Generate with: # openvpn --genkey --secret ta.key # # The server and each client must have # a copy of this key. # The second parameter should be '0' # on the server and '1' on the clients. ;tls-auth ta.key 0 # This file is secret # Select a cryptographic cipher. # This config item must be copied to # the client config file as well. ;cipher BF-CBC # Blowfish (default) ;cipher AES-128-CBC # AES ;cipher DES-EDE3-CBC # Triple-DES # Enable compression on the VPN link. # If you enable it here, you must also # enable it in the client config file. comp-lzo # The maximum number of concurrently connected # clients we want to allow. ;max-clients 100 # It's a good idea to reduce the OpenVPN # daemon's privileges after initialization. # # You can uncomment this out on # non-Windows systems. ;user nobody ;group nobody # The persist options will try to avoid # accessing certain resources on restart # that may no longer be accessible because # of the privilege downgrade. persist-key persist-tun # Output a short status file showing # current connections, truncated # and rewritten every minute. status openvpn-status.log # By default, log messages will go to the syslog (or # on Windows, if running as a service, they will go to # the "\Program Files\OpenVPN\log" directory). # Use log or log-append to override this default. # "log" will truncate the log file on OpenVPN startup, # while "log-append" will append to it. Use one # or the other (but not both). ;log openvpn.log ;log-append openvpn.log # Set the appropriate level of log # file verbosity. # # 0 is silent, except for fatal errors # 4 is reasonable for general usage # 5 and 6 can help to debug connection problems # 9 is extremely verbose verb 3 # Silence repeating messages. At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20 I have changed IP's for security

    Read the article

  • Innovative SPARC: Lighting a Fire Under Oracle's New Hardware Business

    - by Paulo Folgado
    "There's a certain level of things you can do with commercially available parts," says Oracle Executive Vice President Mike Splain. But, he notes, you can do so much more if you design the parts yourself. Mike Splain,EVP, OracleYou can, for example, design cryptographic accelerators into your microprocessors so customers can run their networks fully encrypted if they choose.Of course, it helps if you've already built multiple processing "cores" into those chips so they can handle all that encrypting and decrypting while still getting their other work done.System on a ChipAs the leader of Oracle Microelectronics, Mike knows how implementing clever innovations in silicon can give systems a real competitive advantage.The SPARC microprocessors that his team designed at Sun pioneered the concept of multiple cores several years ago, and the UltraSPARC T2 processor--the industry's first "system on a chip"--packs up to eight cores per chip, each running as many as eight threads at once. That's the most cores and threads of any general-purpose processor. Looking back, Mike points out that the real value of large enterprise-class servers was their ability to run a lot of very large applications in parallel."The beauty of our CMT [chip multi-threading] machines is you can get that same kind of parallel-processing capability at a much lower cost and in a much smaller footprint," he says.The Whole StackWhat has Mike excited these days is that suddenly the opportunity to innovate is much bigger as part of Oracle."In my group, we used to look up the software stack and say, 'We can do any innovation we want, provided the only thing we have to change is what's in the Solaris operating system'--or maybe Java," he says. "If we wanted to change things beyond that, we'd have to go outside the walls of Sun and we'd have to convince the vendors: 'You have to align with us, you have to test with us, you have to build for us, and then you'll reap the benefits.' Now we get access to the entire stack. We can look all the way through the stack and say, 'Okay, what would make the database go faster? What would make the middleware go faster?'"Changing the WorldMike and his microelectronics team also like the fact that Oracle is not just any software company. We're #1 in database, middleware, business intelligence, and more."We're like all the other engineers from Sun; we believe we can change the world, if we can just figure out how to get people to pay attention to us," he says. "Now there's a mechanism at Oracle--much more so than we ever had at Sun."He notes, too, that every innovation in SPARC has involved some combination of hardware and softwareoptimization."Take our cryptography framework, for example. Sure, we can accelerate rapidly, but the Solaris OS has to provide the right set of interfaces that applications can tap into," Mike says. "Same thing with our multicore architecture. We have to have software that can utilize all those threads and run in parallel." His engineers, he points out, have never been interested in producing chips that sell as mere components."Our chips are always designed to go into systems and be combined with various pieces of software," he says. "Our job is to enable the creation of systems."

    Read the article

  • October 2012 Critical Patch Update and Critical Patch Update for Java SE Released

    - by Eric P. Maurice
    Hi, this is Eric Maurice. Oracle has just released the October 2012 Critical Patch Update and the October 2012 Critical Patch Update for Java SE.  As a reminder, the release of security patches for Java SE continues to be on a different schedule than for other Oracle products due to commitments made to customers prior to the Oracle acquisition of Sun Microsystems.  We do however expect to ultimately bring Java SE in line with the regular Critical Patch Update schedule, thus increasing the frequency of scheduled security releases for Java SE to 4 times a year (as opposed to the current 3 yearly releases).  The schedules for the “normal” Critical Patch Update and the Critical Patch Update for Java SE are posted online on the Critical Patch Updates and Security Alerts page. The October 2012 Critical Patch Update provides a total of 109 new security fixes across a number of product families including: Oracle Database Server, Oracle Fusion Middleware, Oracle E-Business Suite, Supply Chain Products Suite, Oracle PeopleSoft Enterprise, Oracle Customer Relationship Management (CRM), Oracle Industry Applications, Oracle FLEXCUBE, Oracle Sun products suite, Oracle Linux and Virtualization, and Oracle MySQL. Out of these 109 new vulnerabilities, 5 affect Oracle Database Server.  The most severe of these Database vulnerabilities has received a CVSS Base Score of 10.0 on Windows platforms and 7.5 on Linux and Unix platforms.  This vulnerability (CVE-2012-3137) is related to the “Cryptographic flaws in Oracle Database authentication protocol” disclosed at the Ekoparty Conference.  Because of timing considerations (proximity to the release date of the October 2012 Critical Patch Update) and the need to extensively test the fixes for this vulnerability to ensure compatibility across the products stack, the fixes for this vulnerability were not released through a Security Alert, but instead mitigation instructions were provided prior to the release of the fixes in this Critical Patch Update in My Oracle Support Note 1492721.1.  Because of the severity of these vulnerabilities, Oracle recommends that this Critical Patch Update be installed as soon as possible. Another 26 vulnerabilities fixed in this Critical Patch Update affect Oracle Fusion Middleware.  The most severe of these Fusion Middleware vulnerabilities has received a CVSS Base Score of 10.0; it affects Oracle JRockit and is related to Java vulnerabilities fixed in the Critical Patch Update for Java SE.  The Oracle Sun products suite gets 18 new security fixes with this Critical Patch Update.  Note also that Oracle MySQL has received 14 new security fixes; the most severe of these MySQL vulnerabilities has received a CVSS Base Score of 9.0. Today’s Critical Patch Update for Java SE provides 30 new security fixes.  The most severe CVSS Base Score for these Java SE vulnerabilities is 10.0 and this score affects 10 vulnerabilities.  As usual, Oracle reports the most severe CVSS Base Score, and these CVSS 10.0s assume that the user running a Java Applet or Java Web Start application has administrator privileges (as is typical on Windows XP). However, when the user does not run with administrator privileges (as is typical on Solaris and Linux), the corresponding CVSS impact scores for Confidentiality, Integrity, and Availability are "Partial" instead of "Complete", typically lowering the CVSS Base Score to 7.5 denoting that the compromise does not extend to the underlying Operating System.  Also, as is typical in the Critical Patch Update for Java SE, most of the vulnerabilities affect Java and Java FX client deployments only.  Only 2 of the Java SE vulnerabilities fixed in this Critical Patch Update affect client and server deployments of Java SE, and only one affects server deployments of JSSE.  This reflects the fact that Java running on servers operate in a more secure and controlled environment.  As discussed during a number of sessions at JavaOne, Oracle is considering security enhancements for Java in desktop and browser environments.  Finally, note that the Critical Patch Update for Java SE is cumulative, in other words it includes all previously released security fixes, including the fix provided through Security Alert CVE-2012-4681, which was released on August 30, 2012. For More Information: The October 2012 Critical Patch Update advisory is located at http://www.oracle.com/technetwork/topics/security/cpuoct2012-1515893.html The October 2012 Critical Patch Update for Java SE advisory is located at http://www.oracle.com/technetwork/topics/security/javacpuoct2012-1515924.html.  An online video about the importance of keeping up with Java releases and the use of the Java auto update is located at http://medianetwork.oracle.com/video/player/1218969104001 More information about Oracle Software Security Assurance is located at http://www.oracle.com/us/support/assurance/index.html  

    Read the article

  • Standards Corner: Preventing Pervasive Monitoring

    - by independentid
     Phil Hunt is an active member of multiple industry standards groups and committees and has spearheaded discussions, creation and ratifications of industry standards including the Kantara Identity Governance Framework, among others. Being an active voice in the industry standards development world, we have invited him to share his discussions, thoughts, news & updates, and discuss use cases, implementation success stories (and even failures) around industry standards on this monthly column. Author: Phil Hunt On Wednesday night, I watched NBC’s interview of Edward Snowden. The past year has been tumultuous one in the IT security industry. There has been some amazing revelations about the activities of governments around the world; and, we have had several instances of major security bugs in key security libraries: Apple's ‘gotofail’ bug  the OpenSSL Heartbleed bug, not to mention Java’s zero day bug, and others. Snowden’s information showed the IT industry has been underestimating the need for security, and highlighted a general trend of lax use of TLS and poorly implemented security on the Internet. This did not go unnoticed in the standards community and in particular the IETF. Last November, the IETF (Internet Engineering Task Force) met in Vancouver Canada, where the issue of “Internet Hardening” was discussed in a plenary session. Presentations were given by Bruce Schneier, Brian Carpenter,  and Stephen Farrell describing the problem, the work done so far, and potential IETF activities to address the problem pervasive monitoring. At the end of the presentation, the IETF called for consensus on the issue. If you know engineers, you know that it takes a while for a large group to arrive at a consensus and this group numbered approximately 3000. When asked if the IETF should respond to pervasive surveillance attacks? There was an overwhelming response for ‘Yes'. When it came to 'No', the room echoed in silence. This was just the first of several consensus questions that were each overwhelmingly in favour of response. This is the equivalent of a unanimous opinion for the IETF. Since the meeting, the IETF has followed through with the recent publication of a new “best practices” document on Pervasive Monitoring (RFC 7258). This document is extremely sensitive in its approach and separates the politics of monitoring from the technical ones. Pervasive Monitoring (PM) is widespread (and often covert) surveillance through intrusive gathering of protocol artefacts, including application content, or protocol metadata such as headers. Active or passive wiretaps and traffic analysis, (e.g., correlation, timing or measuring packet sizes), or subverting the cryptographic keys used to secure protocols can also be used as part of pervasive monitoring. PM is distinguished by being indiscriminate and very large scale, rather than by introducing new types of technical compromise. The IETF community's technical assessment is that PM is an attack on the privacy of Internet users and organisations. The IETF community has expressed strong agreement that PM is an attack that needs to be mitigated where possible, via the design of protocols that make PM significantly more expensive or infeasible. Pervasive monitoring was discussed at the technical plenary of the November 2013 IETF meeting [IETF88Plenary] and then through extensive exchanges on IETF mailing lists. This document records the IETF community's consensus and establishes the technical nature of PM. The draft goes on to further qualify what it means by “attack”, clarifying that  The term is used here to refer to behavior that subverts the intent of communicating parties without the agreement of those parties. An attack may change the content of the communication, record the content or external characteristics of the communication, or through correlation with other communication events, reveal information the parties did not intend to be revealed. It may also have other effects that similarly subvert the intent of a communicator.  The past year has shown that Internet specification authors need to put more emphasis into information security and integrity. The year also showed that specifications are not good enough. The implementations of security and protocol specifications have to be of high quality and superior testing. I’m proud to say Oracle has been a strong proponent of this, having already established its own secure coding practices. 

    Read the article

  • Isis Finally Rolls Out

    - by David Dorf
    Google has rolled their wallet out for several chains; I see the NFC readers in Walgreen's when I'm sent their for milk.  But Isis has been relatively quiet until now.  As of last week they have finally launched in their two test cities: Austin, and Salt Lake City.  Below are the supported carriers and phones as of now, but more phones will be added later. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} AT&T supports: HTC One™ X, LG Escape™, Samsung Galaxy Exhilarate™, Samsung Galaxy S® III, Samsung Galaxy Rugby Pro™ T-Mobile supports: Samsung Galaxy S® II, Samsung Galaxy S® III, Samsung Galaxy S® Relay 4G Verizon supports: Droid Incredible 4G LTE. Of course iPhone owners have no wallet since Apple didn't included an NFC chip. To start using Isis, you have to take your NFC-capable phone to your carrier's store to get the SIM replaced with a more sophisticated one that has a secure element configured for Isis.  The "secure element" is the cryptographic logic that secures mobile payments.  Carriers like the secure element in the SIM while non-carriers (like Google) prefer the secure element in the phone's electronics. (I'm not entirely sure if you could support both Isis and Google Wallet on the same phone.  Anybody know?) Then you can download the Isis app from Google Play and load your cards.  Most credit cards are supported, and there's a process to verify the credit cards are valid.  Then you can select from the list of participating retailers to "follow."  Selecting a retailer allows that retailer to give you offers via the app. The app is well done and easy to use.  You can select a default payment type and also switch between them easily.  When the phone is tapped on the reader, there are two exchanges of information.  The payment information is transferred, and then the Isis "SmartTap" information which includes optional loyalty number and digital coupons.  Of course the value of mobile wallets comes from the ease of handling all three data types (i.e. payment, loyalty, offers). There are several advertisements for Isis running now, and my favorite is below.

    Read the article

  • Oh no! My padding's invalid!

    - by Simon Cooper
    Recently, I've been doing some work involving cryptography, and encountered the standard .NET CryptographicException: 'Padding is invalid and cannot be removed.' Searching on StackOverflow produces 57 questions concerning this exception; it's a very common problem encountered. So I decided to have a closer look. To test this, I created a simple project that decrypts and encrypts a byte array: // create some random data byte[] data = new byte[100]; new Random().NextBytes(data); // use the Rijndael symmetric algorithm RijndaelManaged rij = new RijndaelManaged(); byte[] encrypted; // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); encrypted = encryptedStream.ToArray(); } byte[] decrypted; // and decrypt it again using (var decryptor = rij.CreateDecryptor()) using (CryptoStream crypto = new CryptoStream( new MemoryStream(encrypted), decryptor, CryptoStreamMode.Read)) { byte[] decrypted = new byte[data.Length]; crypto.Read(decrypted, 0, decrypted.Length); } Sure enough, I got exactly the same CryptographicException when trying to decrypt the data even in this simple example. Well, I'm obviously missing something, if I can't even get this single method right! What does the exception message actually mean? What am I missing? Well, after playing around a bit, I discovered the problem was fixed by changing the encryption step to this: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) { using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); } encrypted = encryptedStream.ToArray(); } Aaaah, so that's what the problem was. The CryptoStream wasn't flushing all it's data to the MemoryStream before it was being read, and closing the stream causes it to flush everything to the backing stream. But why does this cause an error in padding? Cryptographic padding All symmetric encryption algorithms (of which Rijndael is one) operates on fixed block sizes. For Rijndael, the default block size is 16 bytes. This means the input needs to be a multiple of 16 bytes long. If it isn't, then the input is padded to 16 bytes using one of the padding modes. This is only done to the final block of data to be encrypted. CryptoStream has a special method to flush this final block of data - FlushFinalBlock. Calling Stream.Flush() does not flush the final block, as you might expect. Only by closing the stream or explicitly calling FlushFinalBlock is the final block, with any padding, encrypted and written to the backing stream. Without this call, the encrypted data is 16 bytes shorter than it should be. If this final block wasn't written, then the decryption gets to the final 16 bytes of the encrypted data and tries to decrypt it as the final block with padding. The end bytes don't match the padding scheme it's been told to use, therefore it throws an exception stating what is wrong - what the decryptor expects to be padding actually isn't, and so can't be removed from the stream. So, as well as closing the stream before reading the result, an alternative fix to my encryption code is the following: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); // explicitly flush the final block of data crypto.FlushFinalBlock(); encrypted = encryptedStream.ToArray(); } Conclusion So, if your padding is invalid, make sure that you close or call FlushFinalBlock on any CryptoStream performing encryption before you access the encrypted data. Flush isn't enough. Only then will the final block be present in the encrypted data, allowing it to be decrypted successfully.

    Read the article

  • Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

    - by Mike
    EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

    Read the article

  • Using Fancybox with Google Static Maps

    - by Levi Hackwith
    Setup I have multiple links on a page with the class location_link Each Links rel attribute is equal to a city state combo (i.e.,Omaha, NE) Once the page is loaded, a JavaScript function loops through all of the location_link items and binds a click event to them using jQuery. This click event fires a call to the Fancybox constructor that is supposed to show a Google Map of the location that link is associated with The Problem: Whenever I click on one of the "location links", I get the following error message: The requested content cannot be loaded. Please try again later. Code I've Already Written: function setUpLocationLinks() { locationLinks = $("a.location_link"); locationLinks.click( function() { var me = $(this); console.log(me.attr("href")); $.fancybox( { "showCloseButton" : true, "hideOnContentClick" : true, "titlePosition" : "inside", "title" : me.attr("rel"), "type" : "image" } ) return false; } ); } Research I've Already Done: The Google Static Map API no longer requires an API Key. The following is from the Google Static Maps API Page Note: The Google Static Maps API no longer requires a Maps API key! (Google Maps API Premier customers should instead sign their URLs using a new cryptographic key which will be sent to you. See the Premier documentation for more information.) The The Image URL I'm using does resolve and pulls back the data I need When I put the above mentioned URL into a standard <img> tag, the map shows up just fine. I'd like to pull this off without having to create some sort of dummy <img> tag that I'm constantly switching the src attribute out of. Hopefully, you'll find this information helpful. Please let me know if you have any other questions.

    Read the article

  • Collision Attacks, Message Digests and a Possible solution

    - by Dominar
    I've been doing some preliminary research in the area of message digests. Specifically collision attacks of cryptographic hash functions such as MD5 and SHA-1, such as the Postscript example and X.509 certificate duplicate. From what I can tell in the case of the postscript attack, specific data was generated and embedded within the header of the postscript (which is ignored during rendering) which brought about the internal state of the md5 to a state such that the modified wording of the document would lead to a final MD equivalent to the original. The X.509 took a similar approach where by data was injected within the comment/whitespace of the certificate. Ok so here is my question, and I can't seem to find anyone asking this question: Why isn't the length of ONLY the data being consumed added as a final block to the MD calculation? In the case of X.509 - Why is the whitespace and comments being taken into account as part of the MD? Wouldn't a simple processes such as one of the following be enough to resolve the proposed collision attacks: MD(M + |M|) = xyz MD(M + |M| + |M| * magicseed_0 +...+ |M| * magicseed_n) = xyz where : M : is the message |M| : size of the message MD : is the message digest function (eg: md5, sha, whirlpool etc) xyz : is the acutal message digest value for the message M magicseed_{i}: Is a set random values generated with seed based on the internal-state prior to the size being added. This technqiue should work, as to date all such collision attacks rely on adding more data to the original message. In short, the level of difficulty involved in generating a collision message such that: It not only generates the same MD But is also comprehensible/parsible/compliant and is also the same size as the original message, is immensely difficult if not near impossible. Has this approach ever been discussed? Any links to papers etc would be nice.

    Read the article

  • imagegrabwindow + https = black screen

    - by earls
    I'm doing something stupid and trying to capture thumbnails, snapshots, images of a html webpages. I'm doing something along the lines of: http://stackoverflow.com/questions/443837/how-might-i-obtain-a-snapshot-or-thumbnail-of-a-web-page-using-php DCOM + IE + PHP (imagegrabwindow; example from manual) Everything works PERFECT until I try to capture a HTTPS website... https://mail.google.com for example. imagegrabwindow produces a png, but it only shows the browser. the contents of the browser are black. If I log out of Google, I can capture the browser window and the contents thereof - the second I log in, the contents (not the browser frame) are black screen. Yes, I've increased the timeout (before closing the browser window). IE has clearly loaded the page, it just refuses to render for imagegrabwindow. I've been fighting this long enough I know it's either a permissions problem or a service needs to interact with the desktop. Does anyone have any clue what permissions need to be set or which service needs access? I assumed cryptographic services, but that's run as a network service and trying to change it to interact makes it shout and carry on. This is the last piece of the puzzle, I'd really like to get it working. Thank you!

    Read the article

  • C++ .NET DLL vs C# Managed Code ? (File Encrypting AES-128+XTS)

    - by Ranhiru
    I need to create a Windows Mobile Application (WinMo 6.x - C#) which is used to encrypt/decrypt files. However it is my duty to write the encryption algorithm which is AES-128 along with XTS as the mode of operation. RijndaelManaged just doesn't cut it :( Very much slower than DES and 3DES CryptoServiceProviders :O I know it all depends on how good I am at writing the algorithm in the most efficient way. (And yes I my self have to write it from scratch but i can take a look @ other implementations) Nevertheless, does writing a C++ .NET DLL to create the encryption/decryption algorithm + all the file handling and using it from C# have a significant performance advantage OVER writing the encryption algorithm + file handling in completely managed C# code? If I use C++ .NET to create the encryption algorithm, should I use MFC Smart Device DLL or ATL? What is the difference and is there any impact on which one I choose? And can i just add a reference to the C++ DLL from C# or should I use P/Invoke? I am fairly competent with C# than C++ but performance plays a major role as I have convinced my lecturers that AES is a very efficient cryptographic algorithm for resource constrained devices. Thanx a bunch :)

    Read the article

  • Automate the signature of the update.rdf manifest for my firefox extension

    - by streetpc
    Hello, I'm developing a firefox extension and I'd like to provide automatic update to my beta-testers (who are not tech-savvy). Unfortunately, the update server doesn't provide HTTPS. According to the Extension Developer Guide on signing updates, I have to sign my update.rdf and provide an encoded public key in the install.rdf. There is the McCoy tool to do all of this, but it is an interactive GUI tool and I'd like to automate the extension packaging using an Ant script (as this is part of a much bigger process). I can't find a more precise description of what's happening to sign the update.rdf manifest than below, and McCoy source is an awful lot of javascript. The doc says: The add-on author creates a public/private RSA cryptographic key pair. The public part of the key is DER encoded and then base 64 encoded and added to the add-on's install.rdf as an updateKey entry. (...) Roughly speaking the update information is converted to a string, then hashed using a sha512 hashing algorithm and this hash is signed using the private key. The resultant data is DER encoded then base 64 encoded for inclusion in the update.rdf as an signature entry. I don't know well about DER encoding, but it seems like it needs some parameters. So would anyone know either the full algortihm to sign the update.rdf and install.rdf using a predefined keypair, or a scriptable alternative to McCoy whether a command-line tool like asn1coding will suffise a good/simple developer tutorial on DER encoding

    Read the article

  • ASP.NET 2.0 RijndaelManaged encryption algorithm vs. FIPS

    - by R Rush
    I'm running into an issue with an ASP.NET 2.0 application. Our network folks just upped our security, and now I get the floowing error whenever I try to access the app: "This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms." I've done a little research, and it sounds like ASP.NET uses the RijndaelManaged AES encryption algorithm to encrypt the ViewState of pages... and RijndaelManaged is on the list of algorithms that aren't FIPS compliant. We're certainly not explicitly calling any encryption algorithm... much less anything on the non-compliant list. This ViewState business makes sense to me, I guess. The thing I can't muddle out, though, is what to do about it. I've found a KB article that suggests using a web.config setting to specify a different algorithm... but either that didn't stick, or that algorithm isn't up to snuff, either. So: 1) Is the RijndaelManaged / ViewState thing actually the problem? Or am I barking up the wrong tree? 2) How to I specify what algorithm to use instead of RijndaelManaged? I've got a list of algorithms that are and aren't compliant; I'm just not sure where to plug that information in. Thanks! Richard

    Read the article

  • Using MD5 to generate an encryption key from password?

    - by Charles
    I'm writing a simple program for file encryption. Mostly as an academic exercise but possibly for future serious use. All of the heavy lifting is done with third-party libraries, but putting the pieces together in a secure manner is still quite a challenge for the non-cryptographer. Basically, I've got just about everything working the way I think it should. I'm using 128-bit AES for the encryption with a 128-bit key length. I want users to be able to enter in variable-length passwords, so I decided to hash the password with MD5 and then use the hash as the key. I figured this was acceptable--the key is always supposed to be a secret, so there's no reason to worry about collision attacks. Now that I've implemented this, I ran across a couple articles indicating that this is a bad idea. My question is: why? If a good password is chosen, the cipher is supposed to be strong enough on its own to never reveal the key except via an extraordinary (read: currently infeasible) brute-force effort, right? Should I be using something like PBKDF2 to generate the key or is that just overkill for all but the most extreme cryptographic applications?

    Read the article

< Previous Page | 1 2 3 4 5 6  | Next Page >