code: function sshKeyToPEM(key) {
      assert.string(key, 'ssh_key');
  
      var k = sshpk.parseKey(key, 'ssh');
      return (k.toString('pem'));
    }
docs: Converts an OpenSSH public key (rsa only) to a PKCS#8 PEM file.
  
  The intent of this module is to interoperate with OpenSSL only,
  specifically the node crypto module's `verify` method.
  
  @param {String} key an OpenSSH public key.
  @return {String} PEM encoded form of the RSA public key.
  @throws {TypeError} on bad input.
  @throws {Error} on invalid ssh key formatted data.