cr is a simple tool for creating signature from rsa private keys.

The general idea is dead simple.

#> cr sign -priv ~/.ssh/id_rsa -in data.txt -out signature.txt
#> cr verify -priv ~/.ssh/id_rsa -in data.txt -sig signature.txt
or
#> cr verify -pub ~/.ssh/id_rsa.pem -in data.txt -sig signature.txt
VERIFY SUCCESS

cr requires openssl, it's built using make.

#> make

cr can use both DSA and RSA keys, in the format in which they are generated by using ssh-keygen or openssl genrsa.

This is how you extract your ssh public key from your private.

#> openssl rsa -in ~/.ssh/id_rsa -pubout -out ~/.ssh/id_rsa.pem
or
#> openssl dsa -in ~/.ssh/id_dsa -pubout -out ~/.ssh/id_dsa.pem

Private key decryption is not yet supported.

• ssh-agent integration
• pageant integration
• firefox plugin (!)

Have fun, this is the beginning of something interesting.