Remove passphrase (password) from private RSA key
# http://www.thinkplexx.com/learn/howto/security/ssl/remove-passphrase-password-from-private-rsa-key
openssl rsa -in ~/.ssh/id_rsa -out ~/.ssh/id_rsa_new
mv ~/.ssh/id_rsa ~/.ssh/id_rsa_old
mv ~/.ssh/id_rsa_new ~/.ssh/id_rsa
chmod 400 ~/.ssh/id_rsa