iOS中的3DES加密似乎不加密最后一个块 [英] 3DES encryption in iOS does not seem to encrypt last block

问题描述

  NSString * v_plainText = @1234567890123456789012345678; 
 NSString * plainText =（const void *）[v_plainText UTF8String]; 
 
 size_t plainTextBufferSize = [v_plainText length]; 
 
 size_t bufferPtrSize =（plainTextBufferSize + kCCBlockSize3DES）& 〜（kCCBlockSize3DES  -  1）; 
 size_t movedBytes = 0; 
 uint8_t * bufferPtr = malloc（bufferPtrSize * sizeof（uint8_t））; 
 
 Byte iv [8] = {0,0,0,0,0,0,0,0}; 
 
 NSString * key =（const void *）[@12345678ABCDEFGH！@＃$％^& *UTF8String]; 
 
 CCCryptorStatus ccStatus; 
 ccStatus = CCCrypt（kCCEncrypt，
 kCCAlgorithm3DES，
 kCCOptionPKCS7Padding& kCCModeCBC，
 key，
 kCCKeySize3DES，
 iv，
 plainText，
 plainTextBufferSize，
（void *）bufferPtr，//输出
 bufferPtrSize，
& movedBytes）; 
 
 NSData * result = [NSData dataWithBytes：（const void *）bufferPtr length：（NSUInteger）movedBytes]; 
 NSString * str = [result base64EncodedStringWithOptions：0]; 
  

这给出了这个结果：

geHFnvoept2aKiruo6InSvc7WVPdHNq2

当我在.NET中运行模拟代码时，给我这个结果：

geHFnvoept2aKiruo6InSvc7WVPdHNq2TENQX5q9Beg =

由于某种原因，返回24字节，而输入为28字节。我期望它是32个字节，如.NET版本。我无法确定我在这里做错什么。

解决方案

加密错误是：

  kCCOptionPKCS7Padding& kCCModeCBC，
  

您需要 | code>& 但 kCCModeCBC 不是一个有效的选项，因为CBC是默认模式，不需要任何选项，您只需要：

  kCCOptionPKCS7Padding，
  

不幸的是还有其他的ObjectiveC编码错误，主要是：

  NSString * plainText =（const void *）[v_plainText UTF8字符串]; 
 NSString * key =（const void *）[@12345678ABCDEFGH！@＃$％^& *UTF8String]; 
  

而是使用：

  NSData * plainText = [v_plainText dataUsingEncoding：NSUTF8StringEncoding]; 
 NSData * key = [@12345678ABCDEFGH！@＃$％^& *dataUsingEncoding：NSUTF8StringEncoding]; 
  

以下是转换为使用NSData的完整代码：

  NSString * plainText = @1234567890123456789012345678; 
 NSString * keyText = @12345678ABCDEFGH！@＃$％^& *; 
 
 NSData * plainData = [plainText dataUsingEncoding：NSUTF8StringEncoding]; 
 NSData * keyData = [keyText dataUsingEncoding：NSUTF8StringEncoding]; 
 Byte iv [8] = {0,0,0,0,0,0,0,0}; 
 size_t bufferSize = plainData.length + kCCBlockSize3DES; 
 NSMutableData * cypherData = [NSMutableData dataWithLength：bufferSize]; 
 size_t movedBytes = 0; 
 
 CCCryptorStatus ccStatus; 
 ccStatus = CCCrypt（kCCEncrypt，
 kCCAlgorithm3DES，
 kCCOptionPKCS7Padding，
 keyData.bytes，
 kCCKeySize3DES，
 iv，
 plainData.bytes， 
 plainData.length，
 cypherData.mutableBytes，
 cypherData.length，
& movedBytes）; 
 
 cypherData.length = movedBytes; 
 NSString * str = [cypherData base64EncodedStringWithOptions：0]; 
 NSLog（@str：％@，str）; 
  

Oputput：

str：geHFnvoept2aKiruo6InSvc7WVPdHNq2TENQX5q9Beg =

I have the following code in objective-c

NSString* v_plainText = @"1234567890123456789012345678";
NSString* plainText = (const void *) [v_plainText UTF8String];

size_t plainTextBufferSize = [v_plainText length];

size_t bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
size_t movedBytes = 0;
uint8_t *bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));

Byte iv[8] = {0,0,0,0,0,0,0,0};

NSString *key = (const void *) [@"12345678ABCDEFGH!@#$%^&*" UTF8String];

CCCryptorStatus ccStatus;
ccStatus = CCCrypt(kCCEncrypt,
                   kCCAlgorithm3DES,
                   kCCOptionPKCS7Padding & kCCModeCBC,
                   key,
                   kCCKeySize3DES,
                   iv,
                   plainText,
                   plainTextBufferSize,
                   (void *)bufferPtr, // output
                   bufferPtrSize,
                   &movedBytes);

NSData* result = [NSData dataWithBytes:(const void*)bufferPtr length:(NSUInteger)movedBytes];
NSString* str = [result base64EncodedStringWithOptions:0];

This gives this result:

geHFnvoept2aKiruo6InSvc7WVPdHNq2

When I run simular code in .NET it gives me this result:

geHFnvoept2aKiruo6InSvc7WVPdHNq2TENQX5q9Beg=

For some reason the objective-c version only returns 24 bytes while the input is 28 bytes. I would expect it to be 32 bytes like in the .NET version. I was unable to determine what I'm doing wrong here.

解决方案

The encryption error is:

kCCOptionPKCS7Padding & kCCModeCBC,

You need |, not & but kCCModeCBC is not a valid option and no option is needed because CBC is the default mode, you simply need:

kCCOptionPKCS7Padding,

Unfortunatly there are other objectiveC coding errors, mainly:

NSString* plainText = (const void *) [v_plainText UTF8String];
NSString *key = (const void *) [@"12345678ABCDEFGH!@#$%^&*" UTF8String];

Instead use:

NSData* plainText = [v_plainText dataUsingEncoding:NSUTF8StringEncoding];
NSData *key = [@"12345678ABCDEFGH!@#$%^&*" dataUsingEncoding:NSUTF8StringEncoding];

Here is the complete code converted to use NSData:

NSString* plainText = @"1234567890123456789012345678";
NSString* keyText = @"12345678ABCDEFGH!@#$%^&*";

NSData* plainData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
NSData *keyData = [keyText dataUsingEncoding:NSUTF8StringEncoding];
Byte iv[8] = {0,0,0,0,0,0,0,0};
size_t bufferSize = plainData.length + kCCBlockSize3DES;
NSMutableData *cypherData = [NSMutableData dataWithLength:bufferSize];
size_t movedBytes = 0;

CCCryptorStatus ccStatus;
ccStatus = CCCrypt(kCCEncrypt,
                   kCCAlgorithm3DES,
                   kCCOptionPKCS7Padding,
                   keyData.bytes,
                   kCCKeySize3DES,
                   iv,
                   plainData.bytes,
                   plainData.length,
                   cypherData.mutableBytes,
                   cypherData.length,
                   &movedBytes);

cypherData.length = movedBytes;
NSString* str = [cypherData base64EncodedStringWithOptions:0];
NSLog(@"str: %@", str);

Oputput:

str: geHFnvoept2aKiruo6InSvc7WVPdHNq2TENQX5q9Beg=

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