xs/vendor/golang.org/x/crypto/salsa20/salsa20.go
Russ Magee f5be3578a8 1/3 Updated Makefile to allow VENDOR flag (adds -vendor to version string)
2/3 Added vendor/ dir to lock down dependent pkg versions.
The author of git.schwanenlied.me/yawning/{chacha20,newhope,kyber}.git has copied
their repos to gitlab.com/yawning/ but some imports of chacha20 from newhope still
inconsistently refer to git.schwanenlied.me/, breaking build.
Licenses for chacha20 also changed from CC0 to AGPL, which may or may not be an
issue. Until the two aforementioned issues are resolved, locking to last-good
versions is probably the best way forward for now.

To build with vendored deps, use make VENDOR=1 clean all

3/3 Moved body of CI push script into bacillus/
2020-01-29 17:23:44 -08:00

58 lines
2 KiB
Go

// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package salsa20 implements the Salsa20 stream cipher as specified in https://cr.yp.to/snuffle/spec.pdf.
Salsa20 differs from many other stream ciphers in that it is message orientated
rather than byte orientated. Keystream blocks are not preserved between calls,
therefore each side must encrypt/decrypt data with the same segmentation.
Another aspect of this difference is that part of the counter is exposed as
a nonce in each call. Encrypting two different messages with the same (key,
nonce) pair leads to trivial plaintext recovery. This is analogous to
encrypting two different messages with the same key with a traditional stream
cipher.
This package also implements XSalsa20: a version of Salsa20 with a 24-byte
nonce as specified in https://cr.yp.to/snuffle/xsalsa-20081128.pdf. Simply
passing a 24-byte slice as the nonce triggers XSalsa20.
*/
package salsa20 // import "golang.org/x/crypto/salsa20"
// TODO(agl): implement XORKeyStream12 and XORKeyStream8 - the reduced round variants of Salsa20.
import (
"golang.org/x/crypto/internal/subtle"
"golang.org/x/crypto/salsa20/salsa"
)
// XORKeyStream crypts bytes from in to out using the given key and nonce.
// In and out must overlap entirely or not at all. Nonce must
// be either 8 or 24 bytes long.
func XORKeyStream(out, in []byte, nonce []byte, key *[32]byte) {
if len(out) < len(in) {
panic("salsa20: output smaller than input")
}
if subtle.InexactOverlap(out[:len(in)], in) {
panic("salsa20: invalid buffer overlap")
}
var subNonce [16]byte
if len(nonce) == 24 {
var subKey [32]byte
var hNonce [16]byte
copy(hNonce[:], nonce[:16])
salsa.HSalsa20(&subKey, &hNonce, key, &salsa.Sigma)
copy(subNonce[:], nonce[16:])
key = &subKey
} else if len(nonce) == 8 {
copy(subNonce[:], nonce[:])
} else {
panic("salsa20: nonce must be 8 or 24 bytes")
}
salsa.XORKeyStream(out, in, &subNonce, key)
}