mirror of
https://github.com/muun/recovery.git
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107 lines
2.1 KiB
Go
107 lines
2.1 KiB
Go
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// Copyright (c) 2017 Andreas Auernhammer. All rights reserved.
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// Use of this source code is governed by a license that can be
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// found in the LICENSE file.
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package siphash
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import (
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"encoding/binary"
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"hash"
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)
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// Sum128 returns the 128 bit authenticator for msg using a 128 bit secret key.
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func Sum128(msg []byte, key *[KeySize]byte) [16]byte {
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k0 := binary.LittleEndian.Uint64(key[0:])
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k1 := binary.LittleEndian.Uint64(key[8:])
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var hVal [4]uint64
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hVal[0] = k0 ^ c0
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hVal[1] = k1 ^ c1 ^ 0xee
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hVal[2] = k0 ^ c2
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hVal[3] = k1 ^ c3
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n := len(msg)
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ctr := byte(n)
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if n >= BlockSize {
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n &= (^(BlockSize - 1))
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core(&hVal, msg[:n])
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msg = msg[n:]
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}
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var block [BlockSize]byte
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copy(block[:], msg)
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block[7] = ctr
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var out [16]byte
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finalize128(&out, &hVal, &block)
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return out
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}
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// New128 returns a hash.Hash computing the SipHash-128 checksum.
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// This function returns a non-nil error if len(key) != 16.
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func New128(key []byte) (hash.Hash, error) {
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if k := len(key); k != KeySize {
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return nil, KeySizeError(k)
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}
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h := new(digest128)
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h.key[0] = binary.LittleEndian.Uint64(key)
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h.key[1] = binary.LittleEndian.Uint64(key[8:])
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h.Reset()
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return h, nil
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}
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type digest128 digest64
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func (d *digest128) BlockSize() int { return BlockSize }
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func (d *digest128) Size() int { return 16 }
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func (d *digest128) Reset() {
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d.hVal[0] = d.key[0] ^ c0
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d.hVal[1] = d.key[1] ^ c1 ^ 0xee
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d.hVal[2] = d.key[0] ^ c2
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d.hVal[3] = d.key[1] ^ c3
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d.off = 0
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d.ctr = 0
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}
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func (d *digest128) Write(p []byte) (n int, err error) {
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n = len(p)
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d.ctr += byte(n)
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if d.off > 0 {
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dif := BlockSize - d.off
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if n < dif {
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d.off += copy(d.block[d.off:], p)
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return
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}
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copy(d.block[d.off:], p[:dif])
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core(&(d.hVal), d.block[:])
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p = p[dif:]
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d.off = 0
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}
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if nn := len(p) &^ (BlockSize - 1); nn >= BlockSize {
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core(&(d.hVal), p[:nn])
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p = p[nn:]
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}
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if len(p) > 0 {
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d.off = copy(d.block[:], p)
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}
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return n, nil
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}
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func (d *digest128) Sum(sum []byte) []byte {
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hVal := d.hVal
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block := d.block
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for i := d.off; i < BlockSize-1; i++ {
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block[i] = 0
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}
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block[7] = d.ctr
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var out [16]byte
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finalize128(&out, &hVal, &block)
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return append(sum, out[:]...)
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}
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