yaole
76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
///
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/// Copyright (c) 2018 xdx. All rights reserved.
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///
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/// \file: cipher.go
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///
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/// \brief: SM4's Block interface and its implements
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///
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/// \author: xdx
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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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"xdx.jelly/xgcl/gerrors"
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)
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// BlockSize is the SM4 block size in bytes.
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const BlockSize = 16
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// NewCipher creates and returns a new cipher.Block.
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// it call the newCipher of each platform
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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, gerrors.WithAnnotatingf(ErrInvalidInput, "input key size is %d, want %d", len(key), BlockSize)
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}
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// newCipher is defined on different arch.
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return newCipher(key)
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}
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// newCipherGeneric creates and returns a new cipher.Block.
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func newCipherGeneric(key []byte) (cipher.Block, error) {
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cp := new(sm4Cipher)
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// gen keys
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expandKey(key, cp.encKey[:], cp.decKey[:])
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return cp, nil
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}
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// sm4Cipher is an instance of cipher.Block interface
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type sm4Cipher struct {
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encKey [32]uint32
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decKey [32]uint32
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}
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// Clear implements the Clearable interface
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func (c *sm4Cipher) Clear() {
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for i := 0; i < len(c.decKey); i++ {
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c.decKey[i] = 0
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c.encKey[i] = 0
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}
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}
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func (c *sm4Cipher) BlockSize() int { return BlockSize }
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// 调用前应保证输入一个block
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func (c *sm4Cipher) Encrypt(dst, src []byte) {
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if len(src) < BlockSize {
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panic("xdx.jelly/xgcl/sm/sm4/Encrypt: input not full block")
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}
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if len(dst) < BlockSize {
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panic("xdx.jelly/xgcl/sm/sm4/Encrypt: output not full block")
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}
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encryptBlockGo(c.encKey[:], dst, src)
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}
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func (c *sm4Cipher) Decrypt(dst, src []byte) {
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if len(src) < BlockSize {
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panic("xdx.jelly/xgcl/sm/sm4/Decrypt: input not full block")
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}
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if len(dst) < BlockSize {
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panic("xdx.jelly/xgcl/sm/sm4/Decrypt: output not full block")
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}
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decryptBlockGo(c.decKey[:], dst, src)
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}
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