45 lines
1.3 KiB
V
45 lines
1.3 KiB
V
// HMAC: Keyed-Hashing for Message Authentication implemented in v
|
|
// implementation based on https://tools.ietf.org/html/rfc2104
|
|
module hmac
|
|
|
|
import crypto.internal.subtle
|
|
|
|
const (
|
|
ipad = []byte{len: 256, init: 0x36} // TODO is 256 enough??
|
|
opad = []byte{len: 256, init: 0x5C}
|
|
npad = []byte{len: 256, init: 0}
|
|
)
|
|
|
|
// Returns an HMAC byte array, depending on the hash algorithm used
|
|
pub fn new(key []byte, data []byte, hash_func fn (bytes []byte) []byte, blocksize int) []byte {
|
|
mut b_key := []byte{}
|
|
if key.len <= blocksize {
|
|
b_key = key.clone() // TODO: remove .clone() once https://github.com/vlang/v/issues/6604 gets fixed
|
|
} else {
|
|
b_key = hash_func(key)
|
|
}
|
|
if b_key.len < blocksize {
|
|
b_key << npad[..blocksize - b_key.len]
|
|
}
|
|
mut inner := []byte{}
|
|
for i, b in ipad[..blocksize] {
|
|
inner << b_key[i] ^ b
|
|
}
|
|
inner << data
|
|
inner_hash := hash_func(inner)
|
|
mut outer := []byte{cap: b_key.len}
|
|
for i, b in opad[..blocksize] {
|
|
outer << b_key[i] ^ b
|
|
}
|
|
outer << inner_hash
|
|
digest := hash_func(outer)
|
|
return digest
|
|
}
|
|
|
|
// equal compares 2 MACs for equality, without leaking timing info
|
|
// NB: if the lengths of the 2 MACs are different, probably a completely different
|
|
// hash function was used to generate them => no useful timing information.
|
|
pub fn equal(mac1 []byte, mac2 []byte) bool {
|
|
return subtle.constant_time_compare(mac1, mac2) == 1
|
|
}
|