diff --git a/lib/krb5/crypto.c b/lib/krb5/crypto.c
index ea82bc34a..80a740905 100644
--- a/lib/krb5/crypto.c
+++ b/lib/krb5/crypto.c
@@ -3032,6 +3032,15 @@ krb5_crypto_destroy(krb5_context context,
     return 0;
 }
 
+krb5_error_code
+krb5_crypto_getblocksize(krb5_context context,
+			 krb5_crypto crypto,
+			 size_t *blocksize)
+{
+    *blocksize = crypto->et->blocksize;
+    return 0;
+}
+
 krb5_error_code
 krb5_string_to_key_derived(krb5_context context,
 			   const void *str,