diff --git a/src/plugins/irc/irc-protocol.c b/src/plugins/irc/irc-protocol.c
index 0499bf336..aacb44f4f 100644
--- a/src/plugins/irc/irc-protocol.c
+++ b/src/plugins/irc/irc-protocol.c
@@ -399,21 +399,15 @@ IRC_PROTOCOL_CALLBACK(account)
 
 IRC_PROTOCOL_CALLBACK(authenticate)
 {
-    int arg_data, sasl_mechanism;
-    char *ptr_data, *sasl_username, *sasl_password, *sasl_key, *answer;
+    int sasl_mechanism;
+    char *sasl_username, *sasl_password, *sasl_key, *answer;
     char *sasl_error;
 
-    IRC_PROTOCOL_MIN_ARGS(2);
+    IRC_PROTOCOL_MIN_PARAMS(1);
 
     if (!irc_server_sasl_enabled (server))
         return WEECHAT_RC_OK;
 
-    arg_data = (argv[0][0] == ':') ? 2 : 1;
-    if (arg_data >= argc)
-        return WEECHAT_RC_OK;
-    ptr_data = (argv_eol[arg_data][0] == ':') ?
-        argv_eol[arg_data] + 1 : argv_eol[arg_data];
-
     irc_server_sasl_get_creds (server, &sasl_username, &sasl_password,
                                &sasl_key);
 
@@ -429,22 +423,22 @@ IRC_PROTOCOL_CALLBACK(authenticate)
             break;
         case IRC_SASL_MECHANISM_SCRAM_SHA_1:
             answer = irc_sasl_mechanism_scram (
-                server, "sha1", ptr_data,
+                server, "sha1", params[0],
                 sasl_username, sasl_password, &sasl_error);
             break;
         case IRC_SASL_MECHANISM_SCRAM_SHA_256:
             answer = irc_sasl_mechanism_scram (
-                server, "sha256", ptr_data,
+                server, "sha256", params[0],
                 sasl_username, sasl_password, &sasl_error);
             break;
         case IRC_SASL_MECHANISM_SCRAM_SHA_512:
             answer = irc_sasl_mechanism_scram (
-                server, "sha512", ptr_data,
+                server, "sha512", params[0],
                 sasl_username, sasl_password, &sasl_error);
             break;
         case IRC_SASL_MECHANISM_ECDSA_NIST256P_CHALLENGE:
             answer = irc_sasl_mechanism_ecdsa_nist256p_challenge (
-                server, ptr_data,
+                server, params[0],
                 sasl_username, sasl_key, &sasl_error);
             break;
         case IRC_SASL_MECHANISM_EXTERNAL: