Question

我正在尝试用Java实现TEA（微型加密算法），以对包含音频的byte[]进行编码，大小为512。

这是我的加密功能：

//Encrypt 64bit/8byte buffer with 128bit/16byte key
public byte[] encrypt(int[] data, int[] key) { 
    int x = data[0]; 
    int y = data[1]; 
    ByteBuffer encrypted = ByteBuffer.allocate(8);
    int sum = 0; 
    int constant = 0x9e3779b9; //magic constant

    for (int k = 0; k < 32; ++k) { 
        sum += constant; 
        x += (y << 4 & 0xfffffff0) + key[0] ^ y + sum ^ (y >> 5 & 0x7ffffff) + key[1]; 
        y += (x << 4 & 0xfffffff0) + key[2] ^ x + sum ^ (x >> 5 & 0x7ffffff) + key[3]; 
    }
    encrypted.putInt(x);
    encrypted.putInt(y);
    return encrypted.array();
}

并解密：

public byte[] decrypt(int[] data, int[] key) { 
    int x = data[0]; 
    int y = data[1]; 
    ByteBuffer decrypted = ByteBuffer.allocate(8);
    int sum = 0xC6EF3720; //32*delta
    int constant = 0x9e3779b9; //magic constant

    for (int k = 0; k < 32; ++k) { 
        x -= (x << 4 & 0xfffffff0) + key[2] ^ x + sum ^ (x >> 5 & 0x7ffffff) + key[3]; 
        y -= (y << 4 & 0xfffffff0) + key[0] ^ y + sum ^ (y >> 5 & 0x7ffffff) + key[1]; 
        sum -= constant; 
    }
    decrypted.putInt(x); 
    decrypted.putInt(y);
    return decrypted.array();
}

和我的加密呼叫：

ByteBuffer unwrapEncrypt = ByteBuffer.allocate(512);
int[] encryptionKey = {55555, 8888, 123857, 912029};

//block is a byte[] with length 512
ByteBuffer plainText = ByteBuffer.wrap(block);
for (int j = 0; j < block.length / 8; j++) {
    //Initiate array for int pairs
    int[] plainTextInts = new int[2];
    plainTextInts[0] = plainText.getInt();
    plainTextInts[1] = plainText.getInt();
    //Encrypt and store
    unwrapEncrypt.put(encrypt(plainTextInts, encryptionKey));
}

并解密通话：

ByteBuffer audioToPlay = ByteBuffer.allocate(512);
int[] decryptionKey = {55555, 8888, 123857, 912029};

//audio is a byte[] with length 512
ByteBuffer cipherText = ByteBuffer.wrap(audio);
for (int j = 0; j < audio.length / 8; j++) {
    int[] plainTextInts = new int[2];
    //Initiate array for int pairs
    plainTextInts[0] = cipherText.getInt();
    plainTextInts[1] = cipherText.getInt();
    //Decrypt and store
    audioToPlay.put(decrypt(plainTextInts, decryptionKey));
}

很抱歉，大量代码-我尝试分析发送的音频和接收的解密数据-它们的长度都是正确的，只是完全不同。如果删除这4个代码块，则音频是完美的。谁能发现最新情况？谢谢

Answer 1

与Wikipedia' s description of TEA相比，您的decrpyt()方法似乎有一个错误。您必须交换-=运算符左侧的x和y。以下内容似乎对我有用：

public byte[] decrypt(int[] data, int[] key) { 
    int x = data[0]; 
    int y = data[1]; 
    ByteBuffer decrypted = ByteBuffer.allocate(8);
    int sum = 0xC6EF3720; //32*delta
    int constant = 0x9e3779b9; //magic constant

    for (int k = 0; k < 32; ++k) { 
        y -= (x << 4 & 0xfffffff0) + key[2] ^ x + sum ^ (x >> 5 & 0x7ffffff) + key[3]; 
        x -= (y << 4 & 0xfffffff0) + key[0] ^ y + sum ^ (y >> 5 & 0x7ffffff) + key[1]; 
        sum -= constant; 
    }
    decrypted.putInt(x); 
    decrypted.putInt(y);
    return decrypted.array();
}

Java中的基本加密算法无法解密

1 个答案: