292 lines
8.3 KiB
Go
292 lines
8.3 KiB
Go
/*
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Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package sm4
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import (
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"crypto/cipher"
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"crypto/rand"
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"crypto/x509"
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"encoding/pem"
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"errors"
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"io/ioutil"
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"os"
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"strconv"
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)
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const BlockSize = 16
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type SM4Key []byte
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type KeySizeError int
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// Cipher is an instance of SM4 encryption.
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type Sm4Cipher struct {
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subkeys []uint32
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block1 []uint32
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block2 []byte
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}
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// sm4密钥参量
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var fk = [4]uint32{
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0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc,
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}
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// sm4密钥参量
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var ck = [32]uint32{
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0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
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0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
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0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
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0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
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0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
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0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
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0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
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0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279,
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}
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// sm4密钥参量
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var sbox = [256]uint8{
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0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
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0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
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0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
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0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
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0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
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0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
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0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
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0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
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0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
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0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
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0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
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0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
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0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
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0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
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0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
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0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48,
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}
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func rl(x uint32, i uint8) uint32 { return (x << (i % 32)) | (x >> (32 - (i % 32))) }
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func l0(b uint32) uint32 { return b ^ rl(b, 13) ^ rl(b, 23) }
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func l1(b uint32) uint32 { return b ^ rl(b, 2) ^ rl(b, 10) ^ rl(b, 18) ^ rl(b, 24) }
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func feistel0(x0, x1, x2, x3, rk uint32) uint32 { return x0 ^ l0(p(x1^x2^x3^rk)) }
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func feistel1(x0, x1, x2, x3, rk uint32) uint32 { return x0 ^ l1(p(x1^x2^x3^rk)) }
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//非线性变换τ(.)
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func p(a uint32) uint32 {
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return (uint32(sbox[a>>24]) << 24) ^ (uint32(sbox[(a>>16)&0xff]) << 16) ^ (uint32(sbox[(a>>8)&0xff]) << 8) ^ uint32(sbox[(a)&0xff])
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}
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/*
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func permuteInitialBlock(block []byte) []uint32 {
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b := make([]uint32, 4, 4)
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for i := 0; i < 4; i++ {
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b[i] = (uint32(block[i*4]) << 24) | (uint32(block[i*4+1]) << 16) |
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(uint32(block[i*4+2]) << 8) | (uint32(block[i*4+3]))
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}
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return b
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}
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func permuteFinalBlock(block []uint32) []byte {
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b := make([]byte, 16, 16)
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for i := 0; i < 4; i++ {
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b[i*4] = uint8(block[i] >> 24)
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b[i*4+1] = uint8(block[i] >> 16)
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b[i*4+2] = uint8(block[i] >> 8)
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b[i*4+3] = uint8(block[i])
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}
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return b
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}
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func cryptBlock(subkeys []uint32, dst, src []byte, decrypt bool) {
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var tm uint32
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b := permuteInitialBlock(src)
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for i := 0; i < 32; i++ {
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if decrypt {
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tm = feistel1(b[0], b[1], b[2], b[3], subkeys[31-i])
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} else {
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tm = feistel1(b[0], b[1], b[2], b[3], subkeys[i])
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}
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b[0], b[1], b[2], b[3] = b[1], b[2], b[3], tm
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}
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b[0], b[1], b[2], b[3] = b[3], b[2], b[1], b[0]
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copy(dst, permuteFinalBlock(b))
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}
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*/
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func permuteInitialBlock(b []uint32, block []byte) {
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for i := 0; i < 4; i++ {
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b[i] = (uint32(block[i*4]) << 24) | (uint32(block[i*4+1]) << 16) |
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(uint32(block[i*4+2]) << 8) | (uint32(block[i*4+3]))
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}
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}
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func permuteFinalBlock(b []byte, block []uint32) {
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for i := 0; i < 4; i++ {
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b[i*4] = uint8(block[i] >> 24)
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b[i*4+1] = uint8(block[i] >> 16)
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b[i*4+2] = uint8(block[i] >> 8)
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b[i*4+3] = uint8(block[i])
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}
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}
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func cryptBlock(subkeys []uint32, b []uint32, r []byte, dst, src []byte, decrypt bool) {
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var tm uint32
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permuteInitialBlock(b, src)
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for i := 0; i < 32; i++ {
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if decrypt {
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tm = b[0] ^ l1(p(b[1]^b[2]^b[3]^subkeys[i]))
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// tm = feistel1(b[0], b[1], b[2], b[3], subkeys[31-i])
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} else {
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tm = b[0] ^ l1(p(b[1]^b[2]^b[3]^subkeys[i]))
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// tm = feistel1(b[0], b[1], b[2], b[3], subkeys[i])
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}
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b[0], b[1], b[2], b[3] = b[1], b[2], b[3], tm
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}
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b[0], b[1], b[2], b[3] = b[3], b[2], b[1], b[0]
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permuteFinalBlock(r, b)
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copy(dst, r)
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}
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func generateSubKeys(key []byte) []uint32 {
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subkeys := make([]uint32, 32)
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b := make([]uint32, 4)
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// b := permuteInitialBlock(key)
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permuteInitialBlock(b, key)
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b[0] ^= fk[0]
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b[1] ^= fk[1]
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b[2] ^= fk[2]
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b[3] ^= fk[3]
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for i := 0; i < 32; i++ {
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subkeys[i] = feistel0(b[0], b[1], b[2], b[3], ck[i])
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b[0], b[1], b[2], b[3] = b[1], b[2], b[3], subkeys[i]
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}
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return subkeys
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}
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func EncryptBlock(key SM4Key, dst, src []byte) {
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subkeys := generateSubKeys(key)
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cryptBlock(subkeys, make([]uint32, 4), make([]byte, 16), dst, src, false)
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}
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func DecryptBlock(key SM4Key, dst, src []byte) {
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subkeys := generateSubKeys(key)
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cryptBlock(subkeys, make([]uint32, 4), make([]byte, 16), dst, src, true)
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}
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func ReadKeyFromMem(data []byte, pwd []byte) (SM4Key, error) {
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block, _ := pem.Decode(data)
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if x509.IsEncryptedPEMBlock(block) {
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if block.Type != "SM4 ENCRYPTED KEY" {
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return nil, errors.New("SM4: unknown type")
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}
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if pwd == nil {
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return nil, errors.New("SM4: need passwd")
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}
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data, err := x509.DecryptPEMBlock(block, pwd)
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if err != nil {
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return nil, err
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}
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return data, nil
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}
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if block.Type != "SM4 KEY" {
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return nil, errors.New("SM4: unknown type")
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}
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return block.Bytes, nil
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}
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func ReadKeyFromPem(FileName string, pwd []byte) (SM4Key, error) {
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data, err := ioutil.ReadFile(FileName)
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if err != nil {
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return nil, err
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}
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return ReadKeyFromMem(data, pwd)
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}
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func WriteKeytoMem(key SM4Key, pwd []byte) ([]byte, error) {
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if pwd != nil {
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block, err := x509.EncryptPEMBlock(rand.Reader,
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"SM4 ENCRYPTED KEY", key, pwd, x509.PEMCipherAES256)
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if err != nil {
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return nil, err
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}
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return pem.EncodeToMemory(block), nil
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} else {
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block := &pem.Block{
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Type: "SM4 KEY",
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Bytes: key,
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}
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return pem.EncodeToMemory(block), nil
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}
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}
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func WriteKeyToPem(FileName string, key SM4Key, pwd []byte) (bool, error) {
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var block *pem.Block
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if pwd != nil {
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var err error
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block, err = x509.EncryptPEMBlock(rand.Reader,
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"SM4 ENCRYPTED KEY", key, pwd, x509.PEMCipherAES256)
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if err != nil {
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return false, err
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}
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} else {
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block = &pem.Block{
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Type: "SM4 KEY",
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Bytes: key,
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}
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}
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file, err := os.Create(FileName)
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if err != nil {
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return false, err
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}
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defer file.Close()
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err = pem.Encode(file, block)
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if err != nil {
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return false, nil
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}
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return true, nil
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}
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func (k KeySizeError) Error() string {
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return "SM4: invalid key size " + strconv.Itoa(int(k))
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}
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// NewCipher creates and returns a new cipher.Block.
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func NewCipher(key []byte) (cipher.Block, error) {
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if len(key) != BlockSize {
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return nil, KeySizeError(len(key))
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}
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c := new(Sm4Cipher)
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c.subkeys = generateSubKeys(key)
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c.block1 = make([]uint32, 4)
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c.block2 = make([]byte, 16)
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return c, nil
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}
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func (c *Sm4Cipher) BlockSize() int {
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return BlockSize
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}
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func (c *Sm4Cipher) Encrypt(dst, src []byte) {
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cryptBlock(c.subkeys, c.block1, c.block2, dst, src, false)
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}
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func (c *Sm4Cipher) Decrypt(dst, src []byte) {
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cryptBlock(c.subkeys, c.block1, c.block2, dst, src, true)
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}
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