diff --git a/library/ecjpake.c b/library/ecjpake.c
index b835ac1..464ff51 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -273,7 +273,7 @@
 
     r_len = *(*p)++;
 
-    if( end < *p || (size_t)( end - *p ) < r_len )
+    if( end < *p || (size_t)( end - *p ) < r_len || r_len == 0 )
     {
         ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
         goto cleanup;
@@ -286,13 +286,6 @@
      * Verification
      */
     MBEDTLS_MPI_CHK( ecjpake_hash( md_info, grp, pf, G, &V, X, id, &h ) );
-
-    if( mbedtls_mpi_cmp_int( &r,0 ) == 0 )
-    {
-        ret = MBEDTLS_ERR_ECP_INVALID_KEY;
-        goto cleanup;
-    }
-
     MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( (mbedtls_ecp_group *) grp,
                      &VV, &h, X, &r, G ) );