今天在做des加密的時候,在網(wǎng)上找到這段代碼 挺好用的,demo測試沒什么問題

//加密
-(NSString *)encryptUseDES:(NSString *)plainText andKey:(NSString *)authKey{
    const void *iv  = (const void *) [@"12345678" UTF8String];
    
    NSString *ciphertext = nil;
    
    NSData *textData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [textData length];
    NSInteger bufferLength = (dataLength/1024 +1)*1024;
    unsigned char buffer[bufferLength];
    memset(buffer, 0, sizeof(char) * bufferLength);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
                                          kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding,
                                          [authKey UTF8String],
                                          kCCKeySizeDES,
                                          iv,
                                          [textData bytes],
                                          dataLength,
                                          buffer,
                                          bufferLength,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        ciphertext = [data base64EncodedStringWithOptions:0];
    }
    return ciphertext;
}

但是當(dāng)我們加密長度大于1M的數(shù)據(jù)時 直接崩潰了

image.png

于是查詢出來問題出在這里 創(chuàng)建的buffer 無法在內(nèi)存中分配到足夠大的內(nèi)存

unsigned char buffer[bufferLength];

在大神的指點下?lián)Q了一個分配方式解決了問題

    unsigned char * buffer = (unsigned  char *)malloc(bufferLength);
    memset(buffer, 0, sizeof(char) * bufferLength);

記得最后釋放內(nèi)存

   free(buffer);

完整代碼如下

//加密
-(NSString *)encryptUseDES:(NSString *)plainText andKey:(NSString *)authKey{
    const void *iv  = (const void *) [@"12345678" UTF8String];
    
    NSString *ciphertext = nil;
    
    NSData *textData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
    
    NSUInteger dataLength = [textData length];
    NSInteger bufferLength = (dataLength/1024 +1)*1024;
    //    unsigned char buffer[bufferLength];
    
    unsigned char * buffer = (unsigned  char *)malloc(bufferLength);
    memset(buffer, 0, sizeof(char) * bufferLength);
    size_t numBytesEncrypted = 0;
    
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
                                          kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding,
                                          [authKey UTF8String],
                                          kCCKeySizeDES,
                                          iv,
                                          [textData bytes],
                                          dataLength,
                                          buffer,
                                          bufferLength,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        ciphertext = [data base64EncodedStringWithOptions:0];
    }
    free(buffer);
    return ciphertext;
}