code: function(secret) {
          var keyIv;
          if (!secret) {
            throw new CError('missing secret').log();
          }
          // secret is a Base64 string
          if(secret.isBase64()){
            try {
              keyIv = forge.util.decode64(secret);
            } catch (e) {
              throw new CError('secret not valid').log();
            }
          } else {
            keyIv = secret;
          }
          return keyIv;
        }
docs: Get bytes from a secret key
  
  @param {String} secret The secret in Base64 format
  @return {Bytes} The secret bytes
  @static
  @private