Keys were created with these commands:

 openssl genrsa -f4 -out rsa_priv.pem 2048
 openssl genrsa -f4 -out rsa_priv_wrong_size.pem 128
 openssl genrsa -aes256 -f4 -out rsa_priv_encrypted.pem 2048
   with 'cartman' as passphrase
