diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 4e99a80..5fd8e4c 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -3973,6 +3973,11 @@
         rs_ctx = &ssl->handshake->ecrs_ctx.pk;
 #endif
 
+#if defined(MBEDTLS_USE_TINYCRYPT)
+    if ( uECC_get_rng() == 0 )
+        uECC_set_rng(&mbetls_uecc_rng_wrapper);
+#endif
+
     if( ( ret = mbedtls_pk_sign_restartable( mbedtls_ssl_own_key( ssl ),
                          md_alg, hash_start, hashlen,
                          ssl->out_msg + 6 + offset, &n,