+unsigned long hmac(void *key, int keylen, void *pt, int tlen, void *tag, int *taglen)
+{
+ assert(keylen == 20);
+ assert(*taglen == 20);
+ return ifs[which]->hmac(key, keylen, pt, tlen, tag, taglen);
+}
+
+const char *crypto_errstr(unsigned long err)
+{
+ return ifs[which]->errstr(err);
+}