iOS des加密

des加密主要用CCCrypt函数（只有ios5中有的），这个函数的头文件：
#import CommonCrypto/CommonCryptor.h
主要思路是：
加密：
用CCCrypt函数加密一下，然后用base64编码下，传过去。
解密：
先把收到的数据根据base64，decode一下，然后再解密一下，就得到了。

关于base64编码，网上有很多写好的，直接拿来调用下就好了。

CCCryptorStatus CCCrypt(

CCOperation op,

CCAlgorithm alg,

CCOptions options,

const void *key,

size_t keyLength,

const void *iv,

const void *dataIn,

size_t dataInLength,

void *dataOut,

size_t dataOutAvailable,

size_t *dataOutMoved)

__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_4_0);

网上找来的一个加密解密的文件（稍微改了一下）：

.h文件：

+ (NSString *)encryptWithText:(NSString *)sText theKey:(NSString *)aKey;

+ (NSString *)decryptWithText:(NSString *)sText theKey:(NSString *)aKey;

.m文件：

+ (NSString *)encrypt:(NSString *)sText encryptOrDecrypt:(CCOperation)encryptOperation key:(NSString *)key

{

const void *vplainText;

size_t plainTextBufferSize;

if (encryptOperation == kCCDecrypt)

{

NSData *decryptData = [GTMBase64 decodeData:[sTextdataUsingEncoding:NSUTF8StringEncoding]];

//NSData *decryptData = [GTMBase64 decodeString:sText ];

plainTextBufferSize = [decryptData length];

vplainText = [decryptData bytes];

}

else

{

NSData* encryptData = [sText dataUsingEncoding:NSUTF8StringEncoding];

plainTextBufferSize = [encryptData length];

vplainText = (const void *)[encryptData bytes];

}

uint8_t *bufferPtr = NULL;

size_t bufferPtrSize = 0;

size_t movedBytes = 0;

bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);

bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));

memset((void *)bufferPtr, 0x0, bufferPtrSize);

NSString *initVec = @"12345678";

const void *vkey = (const void *) [key UTF8String];

const void *vinitVec = (const void *) [initVec UTF8String];

CCCryptorStatus ccStatus = CCCrypt(encryptOperation,

kCCAlgorithm3DES,

kCCOptionPKCS7Padding,

vkey,

kCCKeySize3DES,

vinitVec,

vplainText,

plainTextBufferSize,

(void *)bufferPtr,

bufferPtrSize,

&movedBytes);

NSLog(@"%d",ccStatus);

NSString *result = nil;

if (ccStatus == kCCSuccess)

{

if (encryptOperation == kCCDecrypt)

{

result = [[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)bufferPtrlength:(NSUInteger)movedBytes] encoding:NSUTF8StringEncoding] ;

}

else

{

NSData *data = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];

result = [GTMBase64 stringByEncodingData:data];

// NSLog(@"result:%@",result);

// NSData *temp = [GTMBase64 decodeString:result];

}

}

return result;

}

+ (NSString *)encryptWithText:(NSString *)sText theKey:(NSString *)aKey

{

return [self encrypt:sText encryptOrDecrypt:kCCEncrypt key:aKey];

}

+ (NSString *)decryptWithText:(NSString *)sText theKey:(NSString *)aKey

{

return [self encrypt:sText encryptOrDecrypt:kCCDecrypt key:aKey];

}