Search Results

Search found 5434 results on 218 pages for 'digital audio'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 66/218 | < Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >

  • need primitive public key signature with out of band key distribution

    - by Mike D
    I pretty much a complete neophyte at this signature business so I don't know if what I'm asking is nonsense or not. Anyway, here goes... I want to send an out of band message (don't worry about how it gets there) to a program I've written on a distant machine. I want the program to have some confidence the message is legit by attaching a digital signature to the message. The message will be small less than 200 characters. It seems a public key based signature is what I want to use. I could embed the public key in the program. I understand that the program would be vulnerable to attack by anyone who modifies it BUT I'm not too worried about that. The consequences are not dire. I've looked through the MSDN and around the web but the prospect of diving in is daunting. I'm writing in straight c++, no NET framework or other fancy stuff. I've had no experience including NET framework stuff and little luck during previous attempts. Can anyone point me at some very basic resources to get me started? I need to know 1)how to generate the public and private keys 2)how to sign the message 3)how to verify the signature Any help much appreciated. TIA, Mike

    Read the article

  • DSA signature verification input

    - by calccrypto
    What is the data inputted into DSA when PGP signs a message? From RFC4880, i found A Signature packet describes a binding between some public key and some data. The most common signatures are a signature of a file or a block of text, and a signature that is a certification of a User ID. im not sure if it is the entire public key, just the public key packet, or some other derivative of a pgp key packet. whatever it is, i cannot get the DSA signature to verify here is a sample im testing my program on: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 abcd -----BEGIN PGP SIGNATURE----- Version: BCPG v1.39 iFkEARECABkFAk0z65ESHGFiYyAodGVzdCBrZXkpIDw+AAoJEC3Jkh8+bnkusO0A oKG+HPF2Qrsth2zS9pK+eSCBSypOAKDBgC2Z0vf2EgLiiNMk8Bxpq68NkQ== =gq0e -----END PGP SIGNATURE----- Dumped from pgpdump.net Old: Signature Packet(tag 2)(89 bytes) Ver 4 - new Sig type - Signature of a canonical text document(0x01). Pub alg - DSA Digital Signature Algorithm(pub 17) Hash alg - SHA1(hash 2) Hashed Sub: signature creation time(sub 2)(4 bytes) Time - Mon Jan 17 07:11:13 UTC 2011 Hashed Sub: signer's User ID(sub 28)(17 bytes) User ID - abc (test key) <> Sub: issuer key ID(sub 16)(8 bytes) Key ID - 0x2DC9921F3E6E792E Hash left 2 bytes - b0 ed DSA r(160 bits) - a1 be 1c f1 76 42 bb 2d 87 6c d2 f6 92 be 79 20 81 4b 2a 4e DSA s(160 bits) - c1 80 2d 99 d2 f7 f6 12 02 e2 88 d3 24 f0 1c 69 ab af 0d 91 -> hash(DSA q bits) and the public key for it is: -----BEGIN PGP PUBLIC KEY BLOCK----- Version: BCPG v1.39 mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzE kRc30PvmEHI1faQit7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPL Af9IZOv4PI51gg6ICLKzNO9i3bcUx4yeG2vjMOUAvsLkhSTWob0RxWppo6Pn6MOg dMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO7jj/qcGx6hWmsKUr BVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzRtBFhYmMgKHRlc3Qg a2V5KSA8PohGBBMRAgAGBQJNM+p5AAoJEC3Jkh8+bnkuNEoAnj2QnqGtdlTgUXCQ Fyvwk5wiLGPfAJ4jTGTL62nWzsgrCDIMIfEG2shm8bjMBE0z6ngQAgCUlP7AlfO4 XuKGVCs4NvyBpd0KA0m0wjndOHRNSIz44x24vLfTO0GrueWjPMqRRLHO8zLJS/BX O/BHo6ypjN87Af0VPV1hcq20MEW2iujh3hBwthNwBWhtKdPXOndJGZaB7lshLJuW v9z6WyDNXj/SBEiV1gnPm0ELeg8Syhy5pCjMAgCFEc+NkCzcUOJkVpgLpk+VLwrJ /Wi9q+yCihaJ4EEFt/7vzqmrooXWz2vMugD1C+llN6HkCHTnuMH07/E/2dzciEYE GBECAAYFAk0z6nkACgkQLcmSHz5ueS7NTwCdED1P9NhgR2LqwyS+AEyqlQ0d5joA oK9xPUzjg4FlB+1QTHoOhuokxxyN =CTgL -----END PGP PUBLIC KEY BLOCK----- the public key packet of the key is mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzEkRc30PvmEHI1faQi t7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPLAf9IZOv4PI51gg6ICLKzNO9i3bcUx4ye G2vjMOUAvsLkhSTWob0RxWppo6Pn6MOgdMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO 7jj/qcGx6hWmsKUrBVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzR in radix 64 i have tried many different combinations of sha1(< some data + 'abcd'),but the calculated value v never equals r, of the signature i know that the pgp implementation i used to create the key and signature is correct. i also know that my DSA implementation and PGP key data extraction program are correct. thus, the only thing left is the data to hash. what is the correct data to be hashed?

    Read the article

  • Linear feedback shift register?

    - by Mattia Gobbi
    Lately I bumped repeatedly into the concept of LFSR, that I find quite interesting because of its links with different fields and also fascinating in itself. It took me some effort to understand, the final help was this really good page, much better than the (at first) cryptic wikipedia entry. So I wanted to write some small code for a program that worked like a LFSR. To be more precise, that somehow showed how a LFSR works. Here's the cleanest thing I could come up with after some lenghtier attempts (Python): def lfsr(seed, taps): sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor sr, xor = str(xor) + sr[:-1], 0 print sr if sr == seed: break lfsr('11001001', (8,7,6,1)) #example I named "xor" the output of the XOR function, not very correct. However, this is just meant to show how it circles through its possible states, in fact you noticed the register is represented by a string. Not much logical coherence. This can be easily turned into a nice toy you can watch for hours (at least I could :-) def lfsr(seed, taps): import time sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor print time.sleep(0.75) sr, xor = str(xor) + sr[:-1], 0 print sr print time.sleep(0.75) Then it struck me, what use is this in writing software? I heard it can generate random numbers; is it true? how? So, it would be nice if someone could: explain how to use such a device in software development come up with some code, to support the point above or just like mine to show different ways to do it, in any language Also, as theres not much didactic stuff around about this piece of logic and digital circuitry, it would be nice if this could be a place for noobies (like me) to get a better understanding of this thing, or better, to understand what it is and how it can be useful when writing software. Should have made it a community wiki? That said, if someone feels like golfing... you're welcome.

    Read the article

  • Signable, streamable, "readable" archive format?

    - by alexvoda
    Is there any archive format that offers the following: be digitally sign-able with a digital certificate from a trusted source like Verisign - for preventing changes to the file (I am not referring to read only, but in case the file was changed it should no longer be signed telling the user this is not the original file) be stream-able - be able to be opened even if not all of the content has been transfered (also not strictly linearly) be "readable" - be able to read the data without extracting to a temporary folder (AFAIK if you open a file in a zip archive it is extracted first, and this stays true even for zip based formats like OOXML. This is not what I want) be portable - support on at least Windows, Linux and Mac OS X is a must, or at least future support be free of patents - Be open source - also preferably a license that allows commercial use(as far as i know GPL a share-alike licence so it doesn't allow comercial use, BSD on the other hand alows it) Note: Though it may come in handy eventually I can not think right now of a scenario that would require both point 1 and point 2 simultaneously. Or lets leave it a be able to check the signature only when the whole file was downloaded. I am not interested in: being able to be compressed being supported on legacy systems Does any existing archive format fit this description (tar evolutions like DAR and pax come to mind) ? If there is, are there programing libraries available for the above mentioned OSs? If not, would it be hard to create such a thing? EDIT: clarrified piont 5 EDIT 2: added a note to clarify point 1 and 2 P.S.: This is my first question on StackOverflow

    Read the article

  • Digitally sign MS Office (Word, Excel, etc..) and PDF files on the server

    - by Sébastien Nussbaumer
    I need to digitally sign MS Office and PDF files that are stored on a server. I really mean a digital signature that is integrated in the document, according to each specific file formats. This is the process I had in mind : Create a hash of the file's content Send the hash to a custom written java applet in the browser The user encrypts the hash with his/her private key (on an usb token via PKCS#11 for example), thus effectively signing the file. The applet then sends the signature to the server On the server I would then incorporate the signature in the file's (MS Office and PDF files can do that without changing the file's content, probably by just setting some metadata field) What is cool is that you never have to download and upload the complete file to the server again. What is even cooler, the customer doesn't need Office or PDF Writer to sign the files. Parts 2, 3 and 4 are OK for me, my company bought all the JAVA technology I need for that for a previous project I worked on. Problem : I can't seem to find any documentation/examples to do parts 1 and 5 for Office files . Are my google skills failing me this time ? Do you have any pointers to documentation or examples for doing that for MS Office files ? The underlying technology isn't that important to me : I can use Java, .Net, COM, any working technology is OK ! Note : I'm 95% sure I can nail points 1 and 5 for PDF files using iText Thanks ** Edit : If I can't do that with hashes and must download the complete file to the client, it's also possible. But then I still need the documentation to be able to sign Office file... in java this time (from an applet)

    Read the article

  • Core Audio - CARIngBuffer

    - by tech74
    Hi, Im looking at using the CARingBuffer in iPhone SDK 3.1 Developer\Extras\CoreAudio\PublicUtility, however was a little puzzled about some of its methods. Firstly this will only make sense really to anyone who's used this class For example the GetTimebounds,SetTimeBounds, ClipTimeBounds functions what are these actually doing? Also when using it, i get crashes caused by example this method in the main Fetch method - ZeroABL(abl, 0, destStartOffset * mBytesPerFrame); CARingBufferError CARingBuffer::Fetch(AudioBufferList *abl, UInt32 nFrames, SampleTime startRead) { SampleTime endRead = startRead + nFrames; SampleTime startRead0 = startRead; SampleTime endRead0 = endRead; SampleTime size; CARingBufferError err = ClipTimeBounds(startRead, endRead); if (err) return err; size = endRead - startRead; SInt32 destStartOffset = startRead - startRead0; if (destStartOffset 0) { ZeroABL(abl, 0, destStartOffset * mBytesPerFrame); } Here the destStartOffset has become larger than the size of the abl Bufferlist so when a memset is done it exceeds the boundaries of the abl Bufferlist causing the crash. Why hasn't this class got checks in to prevent this.

    Read the article

  • Audio Recording and Playback

    - by Siva
    Hi, I am new to iphone development. In my app, I want to record a voice and play the recorded voice. Now I am trying to do via speak here sample code, but i feel it is too hard to understand with AudioToolbox framework. Somebody saying AudioToolbox framework is too difficult to implement it. is there any other sample with other than AudioToolbox framework or which way is best to do that? Please help me!

    Read the article

  • Audio looping in Objective-C/iPhone

    - by Neurofluxation
    So, I'm finishing up an iPhone App. I have the following code in place to play the file: while(![player isPlaying]) { totalSoundDuration = soundDuration + 0.5; //Gives a half second break between sounds sleep(totalSoundDuration); //Don't play next sound until the previous sound has finished [player play]; //Play sound NSLog(@" \n Sound Finished Playing \n"); //Output to console } For some reason, the sound plays once then the code loops and it outputs the following: Sound Finished Playing Sound Finished Playing Sound Finished Playing etc... This just repeats forever, I don't suppose any of you lovely people can fathom what could be the boggle? Cheers!

    Read the article

  • detecting pauses in a spoken word audio file using pymad, pcm, vad, etc

    - by james
    First I am going to broadly state what I'm trying to do and ask for advice. Then I will explain my current approach and ask for answers to my current problems. Problem I have an MP3 file of a person speaking. I'd like to split it up into segments roughly corresponding to a sentence or phrase. (I'd do it manually, but we are talking hours of data.) If you have advice on how to do this programatically or for some existing utilities, I'd love to hear it. (I'm aware of voice activity detection and I've looked into it a bit, but I didn't see any freely available utilities.) Current Approach I thought the simplest thing would be to scan the MP3 at certain intervals and identify places where the average volume was below some threshold. Then I would use some existing utility to cut up the mp3 at those locations. I've been playing around with pymad and I believe that I've successfully extracted the PCM (pulse code modulation) data for each frame of the mp3. Now I am stuck because I can't really seem to wrap my head around how the PCM data translates to relative volume. I'm also aware of other complicating factors like multiple channels, big endian vs little, etc. Advice on how to map a group of pcm samples to relative volume would be key. Thanks!

    Read the article

  • Audio Reminders

    - by abhishek mishra
    Hi , I am developing a reminder application. A part of it is to have voive notes as reminders. On click of voice notes button i want to start the inbuilt voice recorder. How do i go ahead for it ? Also once it starts i want to retrieve the path where it gets stored so that it can be played automatically on the day the timeline is reached. Is it possible ?

    Read the article

  • HTML5 iPhone Safari Mobile visualize something rather than quicktime symbol when creating an audio t

    - by Antonio Murgia
    I'm writing a very simple webpage in html5 for iPhone. the page is this one Not Working Everything works but in the page from the iPhone i see the quicktime logo with a slash on it and if i tap on it the player shows up the play button and in the background there is the quicktime logo. is it possible to replace the logos with a personal image? thank you in advance.

    Read the article

  • do I need to close an audio Clip?

    - by Michael
    have an application that processes real-time data and is supposed to beep when a certain event occurs. The triggering event can occur multiple times per second, and if the beep is already playing when another event triggers the code is just supposed to ignore it (as opposed to interrupting the current beep and starting a new one). Here is the basic code: Clip clickClip public void prepareProcess() { super.prepareProcess(); clickClip = null; try { clipFile = new File("C:/WINDOWS/Media/CHIMES.wav"); ais = AudioSystem.getAudioInputStream(clipFile); clickClip = AudioSystem.getClip(); clickClip.open(ais); fileIsLoaded = true; } catch (Exception ex) { clickClip = null; fileIsLoaded = false; } } public void playSound() { if (fileIsLoaded) { if ((clickClip==null) || (!clickClip.isRunning())) { try { clickClip.setFramePosition(0); clickClip.start(); } catch (Exception ex) { System.out.println("Cannot play click noise"); ex.printStackTrace(); } } } The prepareProcess method gets run once in the beginning, and the playSound method is called every time a triggering event occurs. My question is: do I need to close the clickClip object? I know I could add an actionListener to monitor for a Stop event, but since the event occurs so frequently I'm worried the extra processing is going to slow down the real-time data collection. The code seems to run fine, but my worry is memory leaks. The code above is based on an example I found while searching the net, but the example used an actionListener to close the Clip specifically "to eliminate memory leaks that would occur when the stop method wasn't implemented". My program is intended to run for hours so any memory leaks I have will cause problems. I'll be honest: I have no idea how to verify whether or not I've got a problem. I'm using Netbeans, and running the memory profiler just gave me a huge list of things that I don't know how to read. This is supposed to be the simple part of the program, and I'm spending hours on it. Any help would be greatly appreciated! Michael

    Read the article

  • Learn mp3 format and audio signal processing

    - by Shankhoneer Chakrovarty
    I am trying to learn the following things: How mp3 file looks like internally? I found this: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html but it seems old. Is there any recent changes to the format? I couldnt find any. How to open a mp3 file in java and look for bytes? I tried using audiostream but I am getting a lot of zeros and signed short integers which nowhere resemble the header/body format as mentioned in the above link. Am I wrong in interpreting the bytes? How to get amplitude, frequency and pitch of a mp3 file? No idea. Can you please suggest some book or tutorial? Can you please help me in getting the solution for the above questions? I am sorry if some questions appear to be naive, I am a just begun to learn mp3. Thanks

    Read the article

  • How to change default audio input device programatically

    - by f34r
    I am looking for a way to set/change default input device inside my application. I have several different recording devices and it is very anoying to go into the control panel and change default recording device. I was looking around and I did not find anything that could help me with the problem. Application is written in c# and it is targeted for Windows Vista / Windows 7.

    Read the article

  • Synchronizing Java Visualizer Audio and Visual

    - by Matt
    I've run into a problem creating a visualizer for .mp3 files in Java. My goal is to create a visualization that runs in time with the .mp3 file being played. I can currently visualize an .mp3 OR play it, but not both at the same time. I am using libraries which may make this trickier than necessary. I currently: Read in the .mp3 as a FileInputStream. a) Convert the FileInputStream into a Bitstream and run the Visualizer OR b) Pass the FileInputStream to a library Play method where it converts it into a Bitstream, decodes it, and plays it. I am using the JLayer library to play and decode the .mp3. My question is: how do I synchronize the two actions so that I can run both at the same time AND they line up (so my visualizations correspond to the changing frequencies). This implies that they finish at the same time as well.

    Read the article

  • AxWindowsMediaPlayer does not play audio/video from url ?

    - by Madhup
    HI, I am using activeXMediaPlayer to play files from url but each time I pass a url to it shows the message , "either the file is corrupted or player does not support the file format u are playing." But when i run the same url on browser the file is downloaded and this downloaded file can be played on the media player. I am not able to find out what the problem is . Because the same cod plays the local file and the downloaded files but not file from url Although the same code worked few months ago for the urls So is this my fault or some server related issues can affect this thing. Please help me I am in big trouble. Regards, Madhup

    Read the article

  • Audio/Voice Visualization

    - by Neurofluxation
    Hey you Objective-C bods. Does anyone know how I would go about changing (transforming) an image based on the input from the Microphone on the iPhone? i.e. When a user speaks into the Mic, the image will pulse or skew. Thanking you!!

    Read the article

  • How to release audio properly? (AVAudioPlayer)

    - by Aluminum
    Hello everyone! I need help with my iOS application ^^,. I want to know if I'm releasing AVAudioPlayer correctly. MyViewController.h #import <UIKit/UIKit.h> @interface MyViewController : UIViewController { NSString *Path; } - (IBAction)Playsound; @end MyViewController.m #import <AVFoundation/AVAudioPlayer.h> #import "MyViewController.h" @implementation MyViewController AVAudioPlayer *Media; - (IBAction)Playsound { Path = [[NSBundle mainBundle] pathForResource:@"Sound" ofType:@"wav"]; Media = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:Path] error:NULL]; [Media play]; } - (void)dealloc { [Media release]; [super viewDidUnload]; } @end

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >