diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 63244a1..4872b69 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -4749,7 +4749,7 @@
                                          unsigned char *mki_value,
                                          size_t mki_len )
 {
-    if ( mki_len > MBEDTLS_DTLS_SRTP_MAX_MKI_LENGTH )
+    if ( mki_len > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH )
     {
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }