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https://github.com/golang/go
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Added XTEA block cipher package to src/pkg/crypto
This is an adaption of the code from http://en.wikipedia.org/wiki/XTEA. The package also implements the block.Cipher interface so that it can be used with the various block modes. R=rsc https://golang.org/cl/157152
This commit is contained in:
Adrian O'Grady
Russ Cox
parent
0400a7f8b1
commit
6ebfd1eff2
@ -36,6 +36,7 @@ DIRS=\
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crypto/subtle\
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crypto/tls\
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crypto/x509\
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crypto/xtea\
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debug/dwarf\
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debug/macho\
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debug/elf\
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12
src/pkg/crypto/xtea/Makefile
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12
src/pkg/crypto/xtea/Makefile
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@ -0,0 +1,12 @@
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# Copyright 2009 The Go Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style
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# license that can be found in the LICENSE file.
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include ../../../Make.$(GOARCH)
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TARG=crypto/xtea
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GOFILES=\
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cipher.go\
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block.go\
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include ../../../Make.pkg
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66
src/pkg/crypto/xtea/block.go
Normal file
66
src/pkg/crypto/xtea/block.go
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@ -0,0 +1,66 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Implementation adapted from Needham and Wheeler's paper:
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http://www.cix.co.uk/~klockstone/xtea.pdf
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A precalculated look up table is used during encryption/decryption for values that are based purely on the key.
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*/
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package xtea
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// XTEA is based on 64 rounds.
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const numRounds = 64
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// blockToUint32 reads an 8 byte slice into two uint32s.
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// The block is treated as big endian.
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func blockToUint32(src []byte) (uint32, uint32) {
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r0 := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3]);
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r1 := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7]);
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return r0, r1;
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}
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// uint32ToBlock writes two unint32s into an 8 byte data block.
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// Values are written as big endian.
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func uint32ToBlock(v0, v1 uint32, dst []byte) {
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dst[0] = byte(v0 >> 24);
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dst[1] = byte(v0 >> 16);
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dst[2] = byte(v0 >> 8);
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dst[3] = byte(v0);
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dst[4] = byte(v1 >> 24);
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dst[5] = byte(v1 >> 16);
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dst[6] = byte(v1 >> 8);
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dst[7] = byte(v1 >> 0);
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}
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// encryptBlock encrypts a single 8 byte block using XTEA.
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func encryptBlock(c *Cipher, src, dst []byte) {
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v0, v1 := blockToUint32(src);
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// Two rounds of XTEA applied per loop
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for i := 0; i < numRounds; {
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v0 += ((v1<<4 ^ v1>>5) + v1) ^ c.table[i];
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i++;
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v1 += ((v0<<4 ^ v0>>5) + v0) ^ c.table[i];
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i++;
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}
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uint32ToBlock(v0, v1, dst);
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}
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// decryptBlock decrypt a single 8 byte block using XTEA.
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func decryptBlock(c *Cipher, src, dst []byte) {
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v0, v1 := blockToUint32(src);
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// Two rounds of XTEA applied per loop
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for i := numRounds; i > 0; {
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i--;
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v1 -= ((v0<<4 ^ v0>>5) + v0) ^ c.table[i];
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i--;
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v0 -= ((v1<<4 ^ v1>>5) + v1) ^ c.table[i];
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}
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uint32ToBlock(v0, v1, dst);
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}
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92
src/pkg/crypto/xtea/cipher.go
Normal file
92
src/pkg/crypto/xtea/cipher.go
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@ -0,0 +1,92 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This package implements XTEA encryption, as defined in Needham and
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// Wheeler's 1997 technical report, "Tea extensions."
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package xtea
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// For details, see http://www.cix.co.uk/~klockstone/xtea.pdf
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import (
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"os";
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"strconv";
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)
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// The XTEA block size in bytes.
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const BlockSize = 8
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// A Cipher is an instance of an XTEA cipher using a particular key.
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// table contains a series of precalculated values that are used each round.
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type Cipher struct {
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table [64]uint32;
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}
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type KeySizeError int
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func (k KeySizeError) String() string {
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return "crypto/xtea: invalid key size " + strconv.Itoa(int(k))
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}
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// NewCipher creates and returns a new Cipher.
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// The key argument should be the XTEA key.
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// XTEA only supports 128 bit (16 byte) keys.
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func NewCipher(key []byte) (*Cipher, os.Error) {
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k := len(key);
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switch k {
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default:
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return nil, KeySizeError(k)
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case 16:
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break
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}
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c := new(Cipher);
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initCipher(c, key);
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return c, nil;
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}
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// BlockSize returns the XTEA block size, 8 bytes.
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// It is necessary to satisfy the Key interface in the
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// package "crypto/modes".
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func (c *Cipher) BlockSize() int { return BlockSize }
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// Encrypt encrypts the 8 byte buffer src using the key and stores the result in dst.
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// Note that for amounts of data larger than a block,
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// it is not safe to just call Encrypt on successive blocks;
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// instead, use an encryption mode like XTEACBC (see modes.go).
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func (c *Cipher) Encrypt(src, dst []byte) { encryptBlock(c, src, dst) }
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// Decrypt decrypts the 8 byte buffer src using the key k and stores the result in dst.
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func (c *Cipher) Decrypt(src, dst []byte) { decryptBlock(c, src, dst) }
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// Reset zeros the table, so that it will no longer appear in the process's memory.
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func (c *Cipher) Reset() {
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for i := 0; i < len(c.table); i++ {
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c.table[i] = 0
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}
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}
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// initCipher initializes the cipher context by creating a look up table
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// of precalculated values that are based on the key.
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func initCipher(c *Cipher, key []byte) {
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// Load the key into four uint32s
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var k [4]uint32;
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for i := 0; i < len(k); i++ {
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j := i << 2; // Multiply by 4
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k[i] = uint32(key[j+0])<<24 | uint32(key[j+1])<<16 | uint32(key[j+2])<<8 | uint32(key[j+3]);
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}
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// Precalculate the table
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const delta = 0x9E3779B9;
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var sum uint32 = 0;
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// Two rounds of XTEA applied per loop
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for i := 0; i < numRounds; {
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c.table[i] = sum + k[sum&3];
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i++;
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sum += delta;
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c.table[i] = sum + k[(sum>>11)&3];
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i++;
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}
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}
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246
src/pkg/crypto/xtea/xtea_test.go
Normal file
246
src/pkg/crypto/xtea/xtea_test.go
Normal file
@ -0,0 +1,246 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package xtea
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import (
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"testing";
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)
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// A sample test key for when we just want to initialise a cipher
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var testKey = []byte{0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF}
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// Test that the block size for XTEA is correct
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func TestBlocksize(t *testing.T) {
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if BlockSize != 8 {
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t.Errorf("BlockSize constant - expected 8, got %d", BlockSize);
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return;
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}
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c, err := NewCipher(testKey);
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if err != nil {
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t.Errorf("NewCipher(%d bytes) = %s", len(testKey), err);
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return;
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}
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result := c.BlockSize();
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if result != 8 {
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t.Errorf("BlockSize function - expected 8, gotr %d", result);
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return;
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}
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}
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// A series of test values to confirm that the Cipher.table array was initialised correctly
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var testTable = []uint32{
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0x00112233, 0x6B1568B8, 0xE28CE030, 0xC5089E2D, 0xC5089E2D, 0x1EFBD3A2, 0xA7845C2A, 0x78EF0917,
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0x78EF0917, 0x172682D0, 0x5B6AC714, 0x822AC955, 0x3DE68511, 0xDC1DFECA, 0x2062430E, 0x3611343F,
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0xF1CCEFFB, 0x900469B4, 0xD448ADF8, 0x2E3BE36D, 0xB6C46BF5, 0x994029F2, 0x994029F2, 0xF3335F67,
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0x6AAAD6DF, 0x4D2694DC, 0x4D2694DC, 0xEB5E0E95, 0x2FA252D9, 0x4551440A, 0x121E10D6, 0xB0558A8F,
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0xE388BDC3, 0x0A48C004, 0xC6047BC0, 0x643BF579, 0xA88039BD, 0x02736F32, 0x8AFBF7BA, 0x5C66A4A7,
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0x5C66A4A7, 0xC76AEB2C, 0x3EE262A4, 0x215E20A1, 0x215E20A1, 0x7B515616, 0x03D9DE9E, 0x1988CFCF,
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0xD5448B8B, 0x737C0544, 0xB7C04988, 0xDE804BC9, 0x9A3C0785, 0x3873813E, 0x7CB7C582, 0xD6AAFAF7,
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0x4E22726F, 0x309E306C, 0x309E306C, 0x8A9165E1, 0x1319EE69, 0xF595AC66, 0xF595AC66, 0x4F88E1DB,
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}
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// Test that the cipher context is initialised correctly
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func TestCipherInit(t *testing.T) {
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c, err := NewCipher(testKey);
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if err != nil {
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t.Errorf("NewCipher(%d bytes) = %s", len(testKey), err);
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return;
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}
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for i := 0; i < len(c.table); i++ {
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if c.table[i] != testTable[i] {
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t.Errorf("NewCipher() failed to initialise Cipher.table[%d] correctly. Expected %08X, got %08X", i, testTable[i], c.table[i]);
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break;
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}
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}
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}
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// Test that invalid key sizes return an error
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func TestInvalidKeySize(t *testing.T) {
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// Test a long key
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key := []byte{
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0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF,
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0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF,
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};
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_, err := NewCipher(key);
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if err == nil {
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t.Errorf("Invalid key size %d didn't result in an error.", len(key))
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}
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// Test a short key
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key = []byte{0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
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_, err = NewCipher(key);
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if err == nil {
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t.Errorf("Invalid key size %d didn't result in an error.", len(key))
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}
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}
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// Test that we can correctly decode some bytes we have encoded
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func TestEncodeDecode(t *testing.T) {
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original := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF};
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input := original;
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output := make([]byte, BlockSize);
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c, err := NewCipher(testKey);
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if err != nil {
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t.Errorf("NewCipher(%d bytes) = %s", len(testKey), err);
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return;
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}
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// Encrypt the input block
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c.Encrypt(input, output);
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// Check that the output does not match the input
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differs := false;
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for i := 0; i < len(input); i++ {
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if output[i] != input[i] {
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differs = true;
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break;
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}
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}
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if differs == false {
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t.Error("Cipher.Encrypt: Failed to encrypt the input block.");
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return;
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}
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// Decrypt the block we just encrypted
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input = output;
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output = make([]byte, BlockSize);
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c.Decrypt(input, output);
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// Check that the output from decrypt matches our initial input
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for i := 0; i < len(input); i++ {
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if output[i] != original[i] {
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t.Errorf("Decrypted byte %d differed. Expected %02X, got %02X\n", i, original[i], output[i]);
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return;
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}
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}
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}
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// Test Vectors
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type CryptTest struct {
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key []byte;
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plainText []byte;
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cipherText []byte;
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}
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var CryptTests = []CryptTest{
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// These were sourced from http://www.freemedialibrary.com/index.php/XTEA_test_vectors
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CryptTest{
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[]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
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[]byte{0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48},
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[]byte{0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5},
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},
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CryptTest{
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[]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
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[]byte{0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41},
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[]byte{0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8},
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},
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CryptTest{
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[]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f},
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[]byte{0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f},
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[]byte{0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41},
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},
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CryptTest{
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48},
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[]byte{0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5},
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},
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CryptTest{
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41},
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[]byte{0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d},
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},
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CryptTest{
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55},
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[]byte{0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41},
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},
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// These vectors are from http://wiki.secondlife.com/wiki/XTEA_Strong_Encryption_Implementation#Bouncy_Castle_C.23_API
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CryptTest{
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0xDE, 0xE9, 0xD4, 0xD8, 0xF7, 0x13, 0x1E, 0xD9},
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},
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CryptTest{
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08},
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[]byte{0x06, 0x5C, 0x1B, 0x89, 0x75, 0xC6, 0xA8, 0x16},
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},
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CryptTest{
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[]byte{0x01, 0x23, 0x45, 0x67, 0x12, 0x34, 0x56, 0x78, 0x23, 0x45, 0x67, 0x89, 0x34, 0x56, 0x78, 0x9A},
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[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
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[]byte{0x1F, 0xF9, 0xA0, 0x26, 0x1A, 0xC6, 0x42, 0x64},
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},
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CryptTest{
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[]byte{0x01, 0x23, 0x45, 0x67, 0x12, 0x34, 0x56, 0x78, 0x23, 0x45, 0x67, 0x89, 0x34, 0x56, 0x78, 0x9A},
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[]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08},
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[]byte{0x8C, 0x67, 0x15, 0x5B, 0x2E, 0xF9, 0x1E, 0xAD},
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||||
},
|
||||
}
|
||||
|
||||
// Test encryption
|
||||
func TestCipherEncrypt(t *testing.T) {
|
||||
for i, tt := range CryptTests {
|
||||
c, err := NewCipher(tt.key);
|
||||
if err != nil {
|
||||
t.Errorf("NewCipher(%d bytes), vector %d = %s", len(tt.key), i, err);
|
||||
continue;
|
||||
}
|
||||
|
||||
out := make([]byte, len(tt.plainText));
|
||||
c.Encrypt(tt.plainText, out);
|
||||
|
||||
for j := 0; j < len(out); j++ {
|
||||
if out[j] != tt.cipherText[j] {
|
||||
t.Errorf("Cipher.Encrypt %d: out[%d] = %02X, expected %02X", i, j, out[j], tt.cipherText[j]);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Test decryption
|
||||
func TestCipherDecrypt(t *testing.T) {
|
||||
for i, tt := range CryptTests {
|
||||
c, err := NewCipher(tt.key);
|
||||
if err != nil {
|
||||
t.Errorf("NewCipher(%d bytes), vector %d = %s", len(tt.key), i, err);
|
||||
continue;
|
||||
}
|
||||
|
||||
out := make([]byte, len(tt.cipherText));
|
||||
c.Decrypt(tt.cipherText, out);
|
||||
|
||||
for j := 0; j < len(out); j++ {
|
||||
if out[j] != tt.plainText[j] {
|
||||
t.Errorf("Cipher.Decrypt %d: out[%d] = %02X, expected %02X", i, j, out[j], tt.plainText[j]);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Test resetting the cipher context
|
||||
func TestReset(t *testing.T) {
|
||||
c, err := NewCipher(testKey);
|
||||
if err != nil {
|
||||
t.Errorf("NewCipher(%d bytes) = %s", len(testKey), err);
|
||||
return;
|
||||
}
|
||||
|
||||
c.Reset();
|
||||
for i := 0; i < len(c.table); i++ {
|
||||
if c.table[i] != 0 {
|
||||
t.Errorf("Cipher.Reset: Failed to clear Cipher.table[%d]. expected 0, got %08X", i, c.table[i]);
|
||||
return;
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user