Puttygen patch for entering passphrases from command line

Submitted by itefix on Thu, 10/03/2011 - 01:10

If you want to use Putty's key generation program Puttygen from a command line, you can use the Unix version. However, as specified in the documentation, it is still required to enter password manually. That behaviour can not be circumvented by redirection either. A small patch (attached) is developed to introduce the option -N for specifying a new passphrase from the command line:

C:\Program  Files (x86)\ICW\bin>puttygen --help
PuTTYgen unidentified build, Mar  2 2011 22:53:04
Usage: puttygen ( keyfile | -t type  ) 
                  
                 
  -t    specify key type when generating (rsa, dsa, rsa1)
  -b    specify number of bits when generating key
  -C    change or specify key comment
  -P    change key passphrase
  -q    quiet: do not display progress bar
  -N    new passphrase 

  -O    specify output type:
           private             output PuTTY private key format
           private-openssh     export OpenSSH private key
           private-sshcom      export ssh.com private key
           public              standard / ssh.com public key
           public-openssh      OpenSSH public key
           fingerprint         output the key fingerprint
  -o    specify output file
  -l    equivalent to `-O fingerprint'
  -L    equivalent to `-O public-openssh'
  -p    equivalent to `-O public'

NB! the patch allows passphrases without spaces only.