ios des3加解密

#define USER_KEY @""
#define initIv    @"12345678"

+ (NSString *)encryptWithText:(NSString *)sText {
    return [self encrypt:sText encryptOrDecrypt:kCCEncrypt key:USER_KEY];
}

+ (NSString *)decryptWithText:(NSString *)sText {
    return [self encrypt:sText encryptOrDecrypt:kCCDecrypt key:USER_KEY];
}

+ (NSString *)encrypt:(NSString *)sText encryptOrDecrypt:(CCOperation)encryptOperation key:(NSString *)key {
    const void *dataIn;
    size_t dataInLength;
    if (encryptOperation == kCCDecrypt) {
        NSData *decryptData = [GTMBase64 decodeData:[sText dataUsingEncoding:NSUTF8StringEncoding]];
        dataInLength = [decryptData length];
        dataIn = [decryptData bytes];
    } else {
        NSData* encryptData = [sText dataUsingEncoding:NSUTF8StringEncoding];
        dataInLength = [encryptData length];
        dataIn = (const void *)[encryptData bytes];
    }
    CCCryptorStatus ccStatus;
    uint8_t *dataOut = NULL;
    size_t dataOutAvailable = 0;
    size_t dataOutMoved = 0;
    
    dataOutAvailable = (dataInLength + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
    dataOut = malloc( dataOutAvailable * sizeof(uint8_t));
    memset((void *)dataOut, 0x0, dataOutAvailable);
    
    const void *vkey = (const void *) [key UTF8String];
    const void *iv = (const void *) [initIv UTF8String];
    
    ccStatus = CCCrypt(encryptOperation,
                       kCCAlgorithm3DES,
                       kCCOptionPKCS7Padding,
                       vkey,
                       kCCKeySize3DES,
                       iv,
                       dataIn,
                       dataInLength,
                       (void *)dataOut,
                       dataOutAvailable,
                       &dataOutMoved);
    
    NSString *result = nil;
    
    if (encryptOperation == kCCDecrypt) {
        result = [[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved] encoding:NSUTF8StringEncoding] ;
    } else {
        NSData *data = [NSData dataWithBytes:(const void *)dataOut length:(NSUInteger)dataOutMoved];
        result = [GTMBase64 stringByEncodingData:data];
    }
    
    return result;
}