Cisco IOS Cookbook, 2nd Edition

Generating RSA Keys

Problem

You want to create a shareable RSA key for authentication or encryption.

Solution

First, you must create the keys on both devices. We recommend using at least 1024-bit keys in production networks:

Router1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#crypto key generate rsa 
The name for the keys will be: Router1.oreilly.com
Choose the size of the key modulus in the range of 360 to 2048 for your
  General Purpose Keys. Choosing a key modulus greater than 512 may take
  a few minutes.

How many bits in the modulus [512]: 1024
Generating RSA keys ...
[OK]

Router1(config)#end
Router1#show crypto key mypubkey rsa  % Key pair was generated at: 01:19:45 EST Mar 1 2003 Key name: Router1.oreilly.com Usage: General Purpose Key Key Data: 30819F30 0D06092A 864886F7 0D010101 05000381 8D003081 89028181 00E68338 D561B2D1 7B8B75D6 7B34F6AF 1710B00B 5B6E9E8D D7183BE6 F08A6342 054EADFC B764DF9C 4592B891 522727F2 14233B47 8F757134 24F03DB3 833C5988 312B11E9 FB6E0E20 4579C0A4 F2062353 4F1C8CE4 410EE57B 9FCEE784 DA7E3852 408E9742 2584DF56 67293F3F F76B6A96 C4D518FB 1A0114BF E2449838 BE5794E2 37020301 0001 % Key pair was generated at: 01:19:52 EST Mar 1 2003 Key name: Router1.oreilly.com.server Usage: Encryption Key Key Data: 307C300D 06092A86 4886F70D 01010105 00036B00 30680261 00BD928A BD5637E6 2265621C 3AC57138 911CA27D 11F40AA1 E657EA26 6EBF654C 952A3319 D421A33C E2ECA87E CD7E050C 8A8FE64D B73954EA BF2ED639 BC6A8F74 5B9550EA 4119E796 ...