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Editing: rc2.go
// From https://cs.opensource.google/go/x/crypto/+/refs/tags/v0.19.0:pkcs12/internal/rc2/rc2.go // Copyright 2015 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 rc2 implements the RC2 cipher /* https://www.ietf.org/rfc/rfc2268.txt http://people.csail.mit.edu/rivest/pubs/KRRR98.pdf This code is licensed under the MIT license. */ package rc2 import ( "crypto/cipher" "encoding/binary" "math/bits" ) // The rc2 block size in bytes const BlockSize = 8 type rc2Cipher struct { k [64]uint16 } // New returns a new rc2 cipher with the given key and effective key length t1 func New(key []byte, t1 int) (cipher.Block, error) { // TODO(dgryski): error checking for key length return &rc2Cipher{ k: expandKey(key, t1), }, nil } func (*rc2Cipher) BlockSize() int { return BlockSize } var piTable = [256]byte{ 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad, } func expandKey(key []byte, t1 int) [64]uint16 { l := make([]byte, 128) copy(l, key) var t = len(key) var t8 = (t1 + 7) / 8 var tm = byte(255 % uint(1<<(8+uint(t1)-8*uint(t8)))) for i := len(key); i < 128; i++ { l[i] = piTable[l[i-1]+l[uint8(i-t)]] } l[128-t8] = piTable[l[128-t8]&tm] for i := 127 - t8; i >= 0; i-- { l[i] = piTable[l[i+1]^l[i+t8]] } var k [64]uint16 for i := range k { k[i] = uint16(l[2*i]) + uint16(l[2*i+1])*256 } return k } func (c *rc2Cipher) Encrypt(dst, src []byte) { r0 := binary.LittleEndian.Uint16(src[0:]) r1 := binary.LittleEndian.Uint16(src[2:]) r2 := binary.LittleEndian.Uint16(src[4:]) r3 := binary.LittleEndian.Uint16(src[6:]) var j int for j <= 16 { // mix r0 r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1) r0 = bits.RotateLeft16(r0, 1) j++ // mix r1 r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2) r1 = bits.RotateLeft16(r1, 2) j++ // mix r2 r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3) r2 = bits.RotateLeft16(r2, 3) j++ // mix r3 r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0) r3 = bits.RotateLeft16(r3, 5) j++ } r0 = r0 + c.k[r3&63] r1 = r1 + c.k[r0&63] r2 = r2 + c.k[r1&63] r3 = r3 + c.k[r2&63] for j <= 40 { // mix r0 r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1) r0 = bits.RotateLeft16(r0, 1) j++ // mix r1 r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2) r1 = bits.RotateLeft16(r1, 2) j++ // mix r2 r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3) r2 = bits.RotateLeft16(r2, 3) j++ // mix r3 r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0) r3 = bits.RotateLeft16(r3, 5) j++ } r0 = r0 + c.k[r3&63] r1 = r1 + c.k[r0&63] r2 = r2 + c.k[r1&63] r3 = r3 + c.k[r2&63] for j <= 60 { // mix r0 r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1) r0 = bits.RotateLeft16(r0, 1) j++ // mix r1 r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2) r1 = bits.RotateLeft16(r1, 2) j++ // mix r2 r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3) r2 = bits.RotateLeft16(r2, 3) j++ // mix r3 r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0) r3 = bits.RotateLeft16(r3, 5) j++ } binary.LittleEndian.PutUint16(dst[0:], r0) binary.LittleEndian.PutUint16(dst[2:], r1) binary.LittleEndian.PutUint16(dst[4:], r2) binary.LittleEndian.PutUint16(dst[6:], r3) } func (c *rc2Cipher) Decrypt(dst, src []byte) { r0 := binary.LittleEndian.Uint16(src[0:]) r1 := binary.LittleEndian.Uint16(src[2:]) r2 := binary.LittleEndian.Uint16(src[4:]) r3 := binary.LittleEndian.Uint16(src[6:]) j := 63 for j >= 44 { // unmix r3 r3 = bits.RotateLeft16(r3, 16-5) r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0) j-- // unmix r2 r2 = bits.RotateLeft16(r2, 16-3) r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3) j-- // unmix r1 r1 = bits.RotateLeft16(r1, 16-2) r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2) j-- // unmix r0 r0 = bits.RotateLeft16(r0, 16-1) r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1) j-- } r3 = r3 - c.k[r2&63] r2 = r2 - c.k[r1&63] r1 = r1 - c.k[r0&63] r0 = r0 - c.k[r3&63] for j >= 20 { // unmix r3 r3 = bits.RotateLeft16(r3, 16-5) r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0) j-- // unmix r2 r2 = bits.RotateLeft16(r2, 16-3) r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3) j-- // unmix r1 r1 = bits.RotateLeft16(r1, 16-2) r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2) j-- // unmix r0 r0 = bits.RotateLeft16(r0, 16-1) r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1) j-- } r3 = r3 - c.k[r2&63] r2 = r2 - c.k[r1&63] r1 = r1 - c.k[r0&63] r0 = r0 - c.k[r3&63] for j >= 0 { // unmix r3 r3 = bits.RotateLeft16(r3, 16-5) r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0) j-- // unmix r2 r2 = bits.RotateLeft16(r2, 16-3) r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3) j-- // unmix r1 r1 = bits.RotateLeft16(r1, 16-2) r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2) j-- // unmix r0 r0 = bits.RotateLeft16(r0, 16-1) r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1) j-- } binary.LittleEndian.PutUint16(dst[0:], r0) binary.LittleEndian.PutUint16(dst[2:], r1) binary.LittleEndian.PutUint16(dst[4:], r2) binary.LittleEndian.PutUint16(dst[6:], r3) }
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