diff --git a/library/lmots.c b/library/lmots.c
index f198718..a172f77 100644
--- a/library/lmots.c
+++ b/library/lmots.c
@@ -415,7 +415,7 @@
         mbedtls_lms_network_bytes_to_unsigned_int( MBEDTLS_LMOTS_TYPE_LEN,
                 key + MBEDTLS_LMOTS_SIG_TYPE_OFFSET );
 
-    if( key_len < MBEDTLS_LMOTS_PUBLIC_KEY_LEN(ctx->params.type) )
+    if( key_len != MBEDTLS_LMOTS_PUBLIC_KEY_LEN(ctx->params.type) )
     {
         return( MBEDTLS_ERR_LMS_BAD_INPUT_DATA );
     }