krb5_derive_key
err = krb5_derive_key (context, enc, inkey, key, &usage);
if ((ret = krb5_derive_key(context, enc, &foldkey, key, &indata)))
if ((ret = krb5_derive_key(context, enc, &tkey, outkey, &input))) {
ret = krb5_derive_key(context, enc, key,
rv = krb5_derive_key(context, enc, key,
rv = krb5_derive_key(context, enc, key, *d_hmac_key, &d1);
extern krb5_error_code krb5_derive_key