gistfile1.md

Get the public key for our selector

[jcoleman@gilda ~]$ dig -t txt googleprd._domainkey.yale.edu

; <<>> DiG 9.9.1-P3-RedHat-9.9.1-9.P3.fc17 <<>> -t txt googleprd._domainkey.yale.edu ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12280 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5

;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;googleprd._domainkey.yale.edu. IN TXT

;; ANSWER SECTION: googleprd._domainkey.yale.edu. 10800 IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDpIW0kMkNWgb44eGDpR1ktuixg72kxQUdGWSask4IkaUPN4l1WQb0dc/5xr/7kYxmtZWruFqX7Kf9uToyBPjescCkfJ1s6MfciCTgxgK7lgumuuAnOZ04BJ8PztQmvZTyXM/TqRz6+5TGbstqcQ1N+nBwOp8rj7Xclw8YVKlo2LwIDAQAB"

;; AUTHORITY SECTION: yale.edu. 10800 IN NS serv1.net.yale.edu. yale.edu. 10800 IN NS serv3.net.yale.edu. yale.edu. 10800 IN NS serv4.net.yale.edu. yale.edu. 10800 IN NS serv2.net.yale.edu.

;; ADDITIONAL SECTION: serv1.net.yale.edu. 10800 IN A 130.132.1.9 serv2.net.yale.edu. 10800 IN A 130.132.1.10 serv3.net.yale.edu. 10800 IN A 130.132.1.11 serv4.net.yale.edu. 10800 IN A 130.132.89.9

;; Query time: 2 msec ;; SERVER: 130.132.1.9#53(130.132.1.9) ;; WHEN: Thu Oct 25 08:11:00 2012 ;; MSG SIZE rcvd: 453

Format it so that openssl can read it. Add line breaks at 78

[jcoleman@gilda ~]$ cat /tmp/key -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDpIW0kMkNWgb44eGDpR1ktuixg72kxQUdGWSask 4IkaUPN4l1WQb0dc /5xr/7kYxmtZWruFqX7Kf9uToyBPjescCkfJ1s6MfciCTgxgK7lgumuuAnOZ 04BJ8PztQmvZTyXM/TqRz6+5TGbstqcQ1N+nBwOp8rj7Xclw8YVKlo2LwIDAQAB -----END PUBLIC KEY-----

Find the key length

[jcoleman@gilda ~]$ openssl rsa -noout -text -pubin < /tmp/key Public-Key: (1024 bit) Modulus: 00:e9:21:6d:24:32:43:56:81:be:38:78:60:e9:47: 59:2d:ba:2c:60:ef:69:31:41:47:46:59:26:ac:93: 82:24:69:43:cd:e2:5d:56:41:bd:1d:73:fe:71:af: fe:e4:63:19:ad:65:6a:ee:16:a5:fb:29:ff:6e:4e: 8c:81:3e:37:ac:70:29:1f:27:5b:3a:31:f7:22:09: 38:31:80:ae:e5:82:e9:ae:b8:09:ce:67:4e:01:27: c3:f3:b5:09:af:65:3c:97:33:f4:ea:47:3e:be:e5: 31:9b:b2:da:9c:43:53:7e:9c:1c:0e:a7:ca:e3:ed: 77:25:c3:c6:15:2a:5a:36:2f Exponent: 65537 (0x10001)