Computing Number of Bits in Public Key

Posted by eb80 on Super User See other posts from Super User or by eb80
Published on 2012-11-19T15:53:30Z Indexed on 2012/11/19 17:02 UTC
Read the original article Hit count: 253

Filed under:

cryptography

|

dkim

I am working with DKIM and trying to compute the public key size of some DKIM signatures. I know from tools that Gmail's is now 2048, but how could I have figured this out myself (i.e., what exact Linux commands and why)?

user@host$ dig txt 20120113._domainkey.gmail.com

; <<>> DiG 9.8.3-P1 <<>> txt 20120113._domainkey.gmail.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52228
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;20120113._domainkey.gmail.com. IN  TXT

;; ANSWER SECTION:
20120113._domainkey.gmail.com. 300 IN   TXT "k=rsa\; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1Kd87/UeJjenpabgbFwh+eBCsSTrqmwIYYvywlbhbqoo2DymndFkbjOVIPIldNs/m40KF+yzMn1skyoxcTUGCQs8g3FgD2Ap3ZB5DekAo5wMmk4wimDO+U8QzI3SD0" "7y2+07wlNWwIt8svnxgdxGkVbbhzY8i+RQ9DpSVpPbF7ykQxtKXkv/ahW3KjViiAH+ghvvIhkx4xYSIc9oSwVmAl5OctMEeWUwg8Istjqz8BZeTWbf41fbNhte7Y+YqZOwq1Sd0DbvYAD9NOZK9vlfuac0598HY+vtSBczUiKERHv1yRbcaQtZFh5wtiRrN04BLUTD21MycBX5jYchHjPY/wIDAQAB"

;; Query time: 262 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Nov 19 10:52:06 2012
;; MSG SIZE  rcvd: 462

© Super User or respective owner

Related posts about cryptography

Visual Basic Cryptography Question

as seen on Stack Overflow - Search for 'Stack Overflow'
I am trying to mimic the results of some C code that uses the OpenSSL library using the system.security.crytography library in the .net 3.5 world, and I can't seem to get it right. I need some help... part of the issue is my understanding of crytography in general. Here's what is supposed to happen: I… >>> More
External iPhone Cryptography Libs

as seen on Stack Overflow - Search for 'Stack Overflow'
Are there any legal problems using external crypto libs in my iPhone application? I know that Apple has to comply to US cryptography export rules but do I as a developer have any responsibility? How does it work? >>> More
MD5 implementation notes

as seen on Programmers - Search for 'Programmers'
While going through RFC1321, I came across the following paragraph: This step uses a 64-element table T[1 ... 64] constructed from the sine function. Let T[i] denote the i-th element of the table, which is equal to the integer part of 4294967296 times abs(sin(i)), where i is in radians… >>> More
What should web programmers know about cryptography?

as seen on Programmers - Search for 'Programmers'
Should programmers who build websites/web applications understand cryptography? I have no idea how most crypographic algorithms work, and I really don't understand the differences between md5/des/aes/etc. Have any of you found any need for an in-depth understanding of cryptography? I haven't needed… >>> More
Java Cryptography Extension

as seen on Programmers - Search for 'Programmers'
I was told that in order to support AES256 encryption inside my Java app that I would need the JCE with Unlimited Strength Jurisdiction Policy Files. I downloaded this from Oracle and unzipped it and I'm only seeing 2 JARs: local_policy.jar; and US_export_polic.jar I just want to confirm I'm… >>> More

Related posts about dkim

DKIM error: dkim=neutral (bad version) header.i=

as seen on Server Fault - Search for 'Server Fault'
Ive been struggling the last couple of hours with setting up DKIM on my Postfix/CentOS 5.3 server. It finally sends and signs the emails, but apparently Google still does not like it. The errors I'm getting are: dkim=neutral (bad version) [email protected] from googles "show original"… >>> More
DKIM passes everywhere apart from Yahoo!

as seen on Server Fault - Search for 'Server Fault'
Hi, I'm using dkim-milter, Postfix on Ubuntu (I think I used these instructions for setting up). Anyway, using the reflectors such as Port25, BlackOps and Altn.com I get passes for DKIM: X-DKIM: OpenDKIM Filter v2.0.1 medusa.blackops.org o2SGTMSg005616 Authentication-Results: medusa.blackops.org;… >>> More
Debian Unstable + Postfix 2.6.5 + dkim-filter 2.8.2 issue

as seen on Server Fault - Search for 'Server Fault'
I have Postfix installed on Debian Unstable, as the title states, the system is completely up-to-date, I have tried to get DKIM signatures working on outgoing mail using dkim-filter 2.8.2. I couldn't use the default Debian way of doing things with sockets, instead I used the Ubuntu way: SOCKET="inet:12345@localhost"` I… >>> More
Getting Exchange to do DKIM

as seen on Server Fault - Search for 'Server Fault'
Having read Jeff's blog post about Email and DKIM, I'm thinking it might be good to DKIM all mail coming out of our Exchange 2003 servers. Whats a good way of going about that? >>> More
DKIM, SPF, PTR records are not working properly with my domain

as seen on Server Fault - Search for 'Server Fault'
I configured my server and well authenticate email system with DKIM key, SPF record and PTR records, when i start to sent out mails from phplist interface to my users ~50000, my domain is spammed by google. In headers, signed by and mailed by tag shows by my domain : appmail.co, I also test my domain… >>> More