RE: passphrase/ssh2

The private keys when stored are pem encoded. I presume you want to
search the file system and find unprotected keys. Provided the file
systems that you are searching are receptive to such a query. If a
private key is encrypted it will say so in the first N bytes of the
file. 

My experience has suggested if the key is encrypted, but the files
indicated as such would necessitate a custom ssh client. It would seem
to me in your favorite scripting or compiled language: check the file to
ensure ascii, open the file, check the first couple of lines to
determine key type: openssh2, openssh.com, putty etc... 
Then pass the next lines to your check functions if you don't find the
crypto notice then its an unprotected file.

I presume you are already versed in the command option the public key
entries can contain such can mitigate much of the risk associated with
an unencrypted private key. 


Best,

JC

>  
> > How can I check if a ssh2 key has a passphrase set or not? I 
> > know the structure of a ssh1 private key but can't find 
> > anything on ssh2.
> >
> > -mike