與Java等效的iOS對稱密鑰加密/解密

Question

我正在嘗試將ios的數據ios加密/解密，而將ios的java的數據加密/解密

- (NSData *) encrypt:(NSData *) dataToEncrypt symmetricKey:(NSData *)symmetricKey context:(CCOperation)encryptOrDecrypt{
    NSUInteger data_length= [dataToEncrypt length];
    uint8_t input_raw_data[data_length];

    //The [dataToEncrypt length] gives the number of chars present in the string.So say there are 10 chars.
    //Now,the getBytes needs to get the raw bytes from this i.e. binary NSData.But suppose the encoding was
    //full 16 bit encoding then the number of bytes needed wd have been double- 20.But as we are using the
    //NSUTF8StringEncoding,the number of byes needed is 1 per char as the chars(even if originally unicode are
    //compressed into an 8 bit UTF8 encoding.)

    [dataToEncrypt getBytes:&input_raw_data length:data_length];

//    [dataToEncrypt getBytes:&input_raw_data maxLength:data_length usedLength:NULL encoding:NSUTF8StringEncoding options:0 range:NSMakeRange(0,data_length) remainingRange:NULL];

    //According to the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t buffer_size           = data_length + kCCBlockSizeAES128;
    void* buffer                 = malloc(buffer_size);
    size_t num_bytes_encrypted   = 0;


    CCCryptorStatus crypt_status = CCCrypt(encryptOrDecrypt, kCCAlgorithmAES128, 0x0000,
                                           [symmetricKey bytes], kCCKeySizeAES128,
                                           NULL,
                                           input_raw_data, data_length,
                                           buffer, buffer_size,
                                           &num_bytes_encrypted);

//    NSLog(@"~~num bytes encrypted: %d",num_bytes_encrypted);
    if (crypt_status == kCCSuccess){
        NSLog(@"~~Data encoded successfully...");
        return [NSData dataWithBytesNoCopy:buffer length:num_bytes_encrypted];
    }

    free(buffer); //free the buffer;
    return nil;

}

我用了這個

Java代碼-

 Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
 String keyString = "keykeykeykeykeykeykeykey";
 byte[] keyBytes = keyString.getBytes("UTF-8"); 
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, "AES"), new IvParameterSpec(new byte[16])); 
byte[] resultBytes = cipher.doFinal("Hallo Welt!".getBytes("UTF8")); 
FileOutputStream out = new FileOutputStream(new File("encryptedFileJava")); 
out.write(resultBytes); out.close();

這是加密的文本-“ Seább| 8” R，

鍵-BW3dKDf2bkDC4Bq9xTdr1g ==

請幫助我或建議我任何解決方案。

謝謝。

Answer 1

您至少有兩個問題：

1. Objective C代碼使用ECB模式，而Java代碼使用CBC模式。 在CCrypt調用中使用零而不是NULL的字節數組來使用IV值為零的CBC模式（如Java代碼）。

2. 由於keyBytes為24個字節長，因此Java將使用AES-192。 CCrypt只會忽略多余的字節。 將AES-192指定為CCrypt或使用128位密鑰（“ keykeykeykeykeyk”應該起作用）。

Answer 2

為了在IOS和Java設備之間進行安全通信，可以使用對稱密鑰加密。

在平台不同的情況下，建議生成的密鑰是純文本密鑰，而不是API生成的密鑰。

在這種情況下，可以使用AES 128位加密。 IOS設備能夠生成對稱密鑰並使用AES加密來加密文本。

以下鏈接提供了使用純文本對稱密鑰進行加密和解密的Java代碼

http://www.java-redefined.com/2015/06/symmetric-key-encryption-ios-java.html