CHACHA20_POLY1305_KEY
exf->setkey(ctx, key, CHACHA20_POLY1305_KEY);
exf->setkey(ctx, key, CHACHA20_POLY1305_KEY);
.minkey = CHACHA20_POLY1305_KEY,
.maxkey = CHACHA20_POLY1305_KEY,
char derived_key[CHACHA20_POLY1305_KEY];
if (len != CHACHA20_POLY1305_KEY)