diff --git a/lib/curl_sasl.h b/lib/curl_sasl.h
index 12f78404c..25ebfe8f2 100644
--- a/lib/curl_sasl.h
+++ b/lib/curl_sasl.h
@@ -77,12 +77,6 @@ CURLcode Curl_sasl_create_cram_md5_message(struct SessionHandle *data,
                                            const char *passwdp,
                                            char **outptr, size_t *outlen);
 
-/* This is used to decode a base64 encoded DIGEST-MD5 challange message */
-CURLcode Curl_sasl_decode_digest_md5_message(const char *chlg64,
-                                             char *nonce, size_t nlen,
-                                             char *realm, size_t rlen,
-                                             char *alg, size_t alen);
-
 /* This is used to generate a base64 encoded DIGEST-MD5 response message */
 CURLcode Curl_sasl_create_digest_md5_message(struct SessionHandle *data,
                                              const char *chlg64,