Files
crypto/chacha20poly1305/chacha20poly1305_generic.go
T
Michael Munday 754cb46fa0 chacha20poly1305: update to use new ChaCha20 API
Use the new streaming API introduced in CL 104856. Performance
change is negligible:

name                       old speed      new speed      delta
Chacha20Poly1305Open_64     131MB/s ± 2%   135MB/s ± 2%  +3.01%  (p=0.000 n=18+18)
Chacha20Poly1305Seal_64     137MB/s ± 2%   141MB/s ± 3%  +2.89%  (p=0.000 n=19+20)
Chacha20Poly1305Open_1350   305MB/s ± 3%   309MB/s ± 2%  +1.38%  (p=0.001 n=19+20)
Chacha20Poly1305Seal_1350   309MB/s ± 2%   311MB/s ± 2%  +0.74%  (p=0.032 n=19+18)
Chacha20Poly1305Open_8K     338MB/s ± 3%   340MB/s ± 2%    ~     (p=0.108 n=19+20)
Chacha20Poly1305Seal_8K     335MB/s ± 4%   342MB/s ± 2%  +1.96%  (p=0.000 n=19+19)

Change-Id: I2232c9d8d8431f30fb85b4b371d78a57e633283e
Reviewed-on: https://go-review.googlesource.com/108657
Run-TryBot: Michael Munday <mike.munday@ibm.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-04-26 23:00:03 +00:00

75 lines
2.3 KiB
Go

// Copyright 2016 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 chacha20poly1305
import (
"encoding/binary"
"golang.org/x/crypto/internal/chacha20"
"golang.org/x/crypto/poly1305"
)
func roundTo16(n int) int {
return 16 * ((n + 15) / 16)
}
func (c *chacha20poly1305) sealGeneric(dst, nonce, plaintext, additionalData []byte) []byte {
ret, out := sliceForAppend(dst, len(plaintext)+poly1305.TagSize)
var polyKey [32]byte
s := chacha20.New(c.key, [3]uint32{
binary.LittleEndian.Uint32(nonce[0:4]),
binary.LittleEndian.Uint32(nonce[4:8]),
binary.LittleEndian.Uint32(nonce[8:12]),
})
s.XORKeyStream(polyKey[:], polyKey[:])
s.Advance() // skip the next 32 bytes
s.XORKeyStream(out, plaintext)
polyInput := make([]byte, roundTo16(len(additionalData))+roundTo16(len(plaintext))+8+8)
copy(polyInput, additionalData)
copy(polyInput[roundTo16(len(additionalData)):], out[:len(plaintext)])
binary.LittleEndian.PutUint64(polyInput[len(polyInput)-16:], uint64(len(additionalData)))
binary.LittleEndian.PutUint64(polyInput[len(polyInput)-8:], uint64(len(plaintext)))
var tag [poly1305.TagSize]byte
poly1305.Sum(&tag, polyInput, &polyKey)
copy(out[len(plaintext):], tag[:])
return ret
}
func (c *chacha20poly1305) openGeneric(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
var tag [poly1305.TagSize]byte
copy(tag[:], ciphertext[len(ciphertext)-16:])
ciphertext = ciphertext[:len(ciphertext)-16]
var polyKey [32]byte
s := chacha20.New(c.key, [3]uint32{
binary.LittleEndian.Uint32(nonce[0:4]),
binary.LittleEndian.Uint32(nonce[4:8]),
binary.LittleEndian.Uint32(nonce[8:12]),
})
s.XORKeyStream(polyKey[:], polyKey[:])
s.Advance() // skip the next 32 bytes
polyInput := make([]byte, roundTo16(len(additionalData))+roundTo16(len(ciphertext))+8+8)
copy(polyInput, additionalData)
copy(polyInput[roundTo16(len(additionalData)):], ciphertext)
binary.LittleEndian.PutUint64(polyInput[len(polyInput)-16:], uint64(len(additionalData)))
binary.LittleEndian.PutUint64(polyInput[len(polyInput)-8:], uint64(len(ciphertext)))
ret, out := sliceForAppend(dst, len(ciphertext))
if !poly1305.Verify(&tag, polyInput, &polyKey) {
for i := range out {
out[i] = 0
}
return nil, errOpen
}
s.XORKeyStream(out, ciphertext)
return ret, nil
}