diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 6905d926ac..5ae6210056 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -1019,14 +1019,14 @@ int mbedtls_ssl_tls13_populate_transform(
 
 #if !defined(MBEDTLS_USE_PSA_CRYPTO)
     if ((ret = mbedtls_cipher_setkey(&transform->cipher_ctx_enc,
-                                     key_enc, mbedtls_cipher_info_get_key_bitlen(cipher_info),
+                                     key_enc, (int) mbedtls_cipher_info_get_key_bitlen(cipher_info),
                                      MBEDTLS_ENCRYPT)) != 0) {
         MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_cipher_setkey", ret);
         return ret;
     }
 
     if ((ret = mbedtls_cipher_setkey(&transform->cipher_ctx_dec,
-                                     key_dec, mbedtls_cipher_info_get_key_bitlen(cipher_info),
+                                     key_dec, (int) mbedtls_cipher_info_get_key_bitlen(cipher_info),
                                      MBEDTLS_DECRYPT)) != 0) {
         MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_cipher_setkey", ret);
         return ret;