diff options
Diffstat (limited to 'libgo/go/internal/x/crypto/internal/chacha20/chacha_generic.go')
-rw-r--r-- | libgo/go/internal/x/crypto/internal/chacha20/chacha_generic.go | 227 |
1 files changed, 0 insertions, 227 deletions
diff --git a/libgo/go/internal/x/crypto/internal/chacha20/chacha_generic.go b/libgo/go/internal/x/crypto/internal/chacha20/chacha_generic.go deleted file mode 100644 index 7ed1cd9b185..00000000000 --- a/libgo/go/internal/x/crypto/internal/chacha20/chacha_generic.go +++ /dev/null @@ -1,227 +0,0 @@ -// 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 ChaCha20 implements the core ChaCha20 function as specified -// in https://tools.ietf.org/html/rfc7539#section-2.3. -package chacha20 - -import ( - "crypto/cipher" - "encoding/binary" -) - -// assert that *Cipher implements cipher.Stream -var _ cipher.Stream = (*Cipher)(nil) - -// Cipher is a stateful instance of ChaCha20 using a particular key -// and nonce. A *Cipher implements the cipher.Stream interface. -type Cipher struct { - key [8]uint32 - counter uint32 // incremented after each block - nonce [3]uint32 - buf [bufSize]byte // buffer for unused keystream bytes - len int // number of unused keystream bytes at end of buf -} - -// New creates a new ChaCha20 stream cipher with the given key and nonce. -// The initial counter value is set to 0. -func New(key [8]uint32, nonce [3]uint32) *Cipher { - return &Cipher{key: key, nonce: nonce} -} - -// XORKeyStream XORs each byte in the given slice with a byte from the -// cipher's key stream. Dst and src must overlap entirely or not at all. -// -// If len(dst) < len(src), XORKeyStream will panic. It is acceptable -// to pass a dst bigger than src, and in that case, XORKeyStream will -// only update dst[:len(src)] and will not touch the rest of dst. -// -// Multiple calls to XORKeyStream behave as if the concatenation of -// the src buffers was passed in a single run. That is, Cipher -// maintains state and does not reset at each XORKeyStream call. -func (s *Cipher) XORKeyStream(dst, src []byte) { - // xor src with buffered keystream first - if s.len != 0 { - buf := s.buf[len(s.buf)-s.len:] - if len(src) < len(buf) { - buf = buf[:len(src)] - } - td, ts := dst[:len(buf)], src[:len(buf)] // BCE hint - for i, b := range buf { - td[i] = ts[i] ^ b - } - s.len -= len(buf) - if s.len != 0 { - return - } - s.buf = [len(s.buf)]byte{} // zero the empty buffer - src = src[len(buf):] - dst = dst[len(buf):] - } - - if len(src) == 0 { - return - } - if haveAsm { - s.xorKeyStreamAsm(dst, src) - return - } - - // set up a 64-byte buffer to pad out the final block if needed - // (hoisted out of the main loop to avoid spills) - rem := len(src) % 64 // length of final block - fin := len(src) - rem // index of final block - if rem > 0 { - copy(s.buf[len(s.buf)-64:], src[fin:]) - } - - // qr calculates a quarter round - qr := func(a, b, c, d uint32) (uint32, uint32, uint32, uint32) { - a += b - d ^= a - d = (d << 16) | (d >> 16) - c += d - b ^= c - b = (b << 12) | (b >> 20) - a += b - d ^= a - d = (d << 8) | (d >> 24) - c += d - b ^= c - b = (b << 7) | (b >> 25) - return a, b, c, d - } - - // ChaCha20 constants - const ( - j0 = 0x61707865 - j1 = 0x3320646e - j2 = 0x79622d32 - j3 = 0x6b206574 - ) - - // pre-calculate most of the first round - s1, s5, s9, s13 := qr(j1, s.key[1], s.key[5], s.nonce[0]) - s2, s6, s10, s14 := qr(j2, s.key[2], s.key[6], s.nonce[1]) - s3, s7, s11, s15 := qr(j3, s.key[3], s.key[7], s.nonce[2]) - - n := len(src) - src, dst = src[:n:n], dst[:n:n] // BCE hint - for i := 0; i < n; i += 64 { - // calculate the remainder of the first round - s0, s4, s8, s12 := qr(j0, s.key[0], s.key[4], s.counter) - - // execute the second round - x0, x5, x10, x15 := qr(s0, s5, s10, s15) - x1, x6, x11, x12 := qr(s1, s6, s11, s12) - x2, x7, x8, x13 := qr(s2, s7, s8, s13) - x3, x4, x9, x14 := qr(s3, s4, s9, s14) - - // execute the remaining 18 rounds - for i := 0; i < 9; i++ { - x0, x4, x8, x12 = qr(x0, x4, x8, x12) - x1, x5, x9, x13 = qr(x1, x5, x9, x13) - x2, x6, x10, x14 = qr(x2, x6, x10, x14) - x3, x7, x11, x15 = qr(x3, x7, x11, x15) - - x0, x5, x10, x15 = qr(x0, x5, x10, x15) - x1, x6, x11, x12 = qr(x1, x6, x11, x12) - x2, x7, x8, x13 = qr(x2, x7, x8, x13) - x3, x4, x9, x14 = qr(x3, x4, x9, x14) - } - - x0 += j0 - x1 += j1 - x2 += j2 - x3 += j3 - - x4 += s.key[0] - x5 += s.key[1] - x6 += s.key[2] - x7 += s.key[3] - x8 += s.key[4] - x9 += s.key[5] - x10 += s.key[6] - x11 += s.key[7] - - x12 += s.counter - x13 += s.nonce[0] - x14 += s.nonce[1] - x15 += s.nonce[2] - - // increment the counter - s.counter += 1 - if s.counter == 0 { - panic("chacha20: counter overflow") - } - - // pad to 64 bytes if needed - in, out := src[i:], dst[i:] - if i == fin { - // src[fin:] has already been copied into s.buf before - // the main loop - in, out = s.buf[len(s.buf)-64:], s.buf[len(s.buf)-64:] - } - in, out = in[:64], out[:64] // BCE hint - - // XOR the key stream with the source and write out the result - xor(out[0:], in[0:], x0) - xor(out[4:], in[4:], x1) - xor(out[8:], in[8:], x2) - xor(out[12:], in[12:], x3) - xor(out[16:], in[16:], x4) - xor(out[20:], in[20:], x5) - xor(out[24:], in[24:], x6) - xor(out[28:], in[28:], x7) - xor(out[32:], in[32:], x8) - xor(out[36:], in[36:], x9) - xor(out[40:], in[40:], x10) - xor(out[44:], in[44:], x11) - xor(out[48:], in[48:], x12) - xor(out[52:], in[52:], x13) - xor(out[56:], in[56:], x14) - xor(out[60:], in[60:], x15) - } - // copy any trailing bytes out of the buffer and into dst - if rem != 0 { - s.len = 64 - rem - copy(dst[fin:], s.buf[len(s.buf)-64:]) - } -} - -// Advance discards bytes in the key stream until the next 64 byte block -// boundary is reached and updates the counter accordingly. If the key -// stream is already at a block boundary no bytes will be discarded and -// the counter will be unchanged. -func (s *Cipher) Advance() { - s.len -= s.len % 64 - if s.len == 0 { - s.buf = [len(s.buf)]byte{} - } -} - -// XORKeyStream crypts bytes from in to out using the given key and counters. -// In and out must overlap entirely or not at all. Counter contains the raw -// ChaCha20 counter bytes (i.e. block counter followed by nonce). -func XORKeyStream(out, in []byte, counter *[16]byte, key *[32]byte) { - s := Cipher{ - key: [8]uint32{ - binary.LittleEndian.Uint32(key[0:4]), - binary.LittleEndian.Uint32(key[4:8]), - binary.LittleEndian.Uint32(key[8:12]), - binary.LittleEndian.Uint32(key[12:16]), - binary.LittleEndian.Uint32(key[16:20]), - binary.LittleEndian.Uint32(key[20:24]), - binary.LittleEndian.Uint32(key[24:28]), - binary.LittleEndian.Uint32(key[28:32]), - }, - nonce: [3]uint32{ - binary.LittleEndian.Uint32(counter[4:8]), - binary.LittleEndian.Uint32(counter[8:12]), - binary.LittleEndian.Uint32(counter[12:16]), - }, - counter: binary.LittleEndian.Uint32(counter[0:4]), - } - s.XORKeyStream(out, in) -} |