diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 3c7dd27..94795f4 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -81,7 +81,7 @@
 
     /* With GCM and CCM, same context can encrypt & decrypt */
     ret = mbedtls_cipher_setkey( &key->ctx, buf,
-                                 mbedtls_cipher_get_key_size( &key->ctx ),
+                                 mbedtls_cipher_get_key_bitlen( &key->ctx ),
                                  MBEDTLS_ENCRYPT );
 
     mbedtls_zeroize( buf, sizeof( buf ) );