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caddy/vendor/github.com/aead/chacha20/chacha20.go
Matthew Holt 6fde3632ef
Vendor all dependencies (Warning: Huge changeset.)
The vendor/ folder was created with the help of @FiloSottile's gvt and
vendorcheck.

Any dependencies of Caddy plugins outside this repo are not vendored.

We do not remove any unused, vendored packages because vendorcheck -u
only checks using the current build configuration; i.e. packages that
may be imported by files toggled by build tags of other systems.

CI tests have been updated to ignore the vendor/ folder. When Go 1.9 is
released, a few of the go commands should be revised to again use ./...
as it will ignore the vendor folder by default.
2017-05-27 13:30:11 -06:00

41 lines
2 KiB
Go

// Copyright (c) 2016 Andreas Auernhammer. All rights reserved.
// Use of this source code is governed by a license that can be
// found in the LICENSE file.
// Package chacha20 implements the ChaCha20 / XChaCha20 stream chipher.
// Notice that one specific key-nonce combination must be unique for all time.
//
// There are three versions of ChaCha20:
// - ChaCha20 with a 64 bit nonce (en/decrypt up to 2^64 * 64 bytes for one key-nonce combination)
// - ChaCha20 with a 96 bit nonce (en/decrypt up to 2^32 * 64 bytes (~256 GB) for one key-nonce combination)
// - XChaCha20 with a 192 bit nonce (en/decrypt up to 2^64 * 64 bytes for one key-nonce combination)
package chacha20 // import "github.com/aead/chacha20"
import (
"crypto/cipher"
"github.com/aead/chacha20/chacha"
)
// XORKeyStream crypts bytes from src to dst using the given nonce and key.
// The length of the nonce determinds the version of ChaCha20:
// - 8 bytes: ChaCha20 with a 64 bit nonce and a 2^64 * 64 byte period.
// - 12 bytes: ChaCha20 as defined in RFC 7539 and a 2^32 * 64 byte period.
// - 24 bytes: XChaCha20 with a 192 bit nonce and a 2^64 * 64 byte period.
// Src and dst may be the same slice but otherwise should not overlap.
// If len(dst) < len(src) this function panics.
// If the nonce is neither 64, 96 nor 192 bits long, this function panics.
func XORKeyStream(dst, src, nonce, key []byte) {
chacha.XORKeyStream(dst, src, nonce, key, 20)
}
// NewCipher returns a new cipher.Stream implementing a ChaCha20 version.
// The nonce must be unique for one key for all time.
// The length of the nonce determinds the version of ChaCha20:
// - 8 bytes: ChaCha20 with a 64 bit nonce and a 2^64 * 64 byte period.
// - 12 bytes: ChaCha20 as defined in RFC 7539 and a 2^32 * 64 byte period.
// - 24 bytes: XChaCha20 with a 192 bit nonce and a 2^64 * 64 byte period.
// If the nonce is neither 64, 96 nor 192 bits long, a non-nil error is returned.
func NewCipher(nonce, key []byte) (cipher.Stream, error) {
return chacha.NewCipher(nonce, key, 20)
}