java如何将从DiffieHellman类生成的AES密钥添加到使用该密钥的类

Question

背景：我有两台通过IP/端口连接进行通信的设备，通过Diffie-Hellman密钥交换建立实时语音加密通信，并通过AES算法进行加密。现在已经编写了一些代码，其中一些只是作为原型实现的示例

问题：现在，即使理解我的类是如何工作的，就像标题中所说的：我也不知道如何从DH类获取密钥，并在AES类中声明这是它必须用来加密的密钥

欢迎提供关于代码优化、更好实践和一般提示的建议。 谢谢你抽出时间

公共类DH扩展线程{

int bitLength=512;  
int certainty=20;//

private static final SecureRandom rnd = new SecureRandom();

public DH() throws Exception{
    Random randomGenerator = new Random();
    BigInteger generatorValue,primeValue,publicA,publicB,secretA,secretB,sharedKeyA,sharedKeyB;

    primeValue = findPrime();// BigInteger.valueOf((long)g);
    System.out.println("the prime is "+primeValue);
     generatorValue = findPrimeRoot(primeValue);//BigInteger.valueOf((long)p);
    System.out.println("the generator of the prime is "+generatorValue);

    // on machine 1
    secretA = new BigInteger(bitLength-2,randomGenerator);
    // on machine 2
    secretB = new BigInteger(bitLength-2,randomGenerator);

    // to be published:
    publicA=generatorValue.modPow(secretA, primeValue);
    publicB=generatorValue.modPow(secretB, primeValue);
    sharedKeyA = publicB.modPow(secretA,primeValue);// should always be same as:
    sharedKeyB = publicA.modPow(secretB,primeValue);

    String getAValue=sharedKeyA.toString();

    MessageDigest md = MessageDigest.getInstance("SHA-256");
    md.update(getAValue.getBytes());

    byte byteData[] = md.digest();
    StringBuffer sb = new StringBuffer();

    for(int i=0;i<byteData.length;i++)
    {
        sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));// ??
    }

    String getHexValue = sb.toString();
    System.out.println("hex format in SHA-256 is "+getHexValue);

    byte [] initkey = getAValue.getBytes("UTF-8");

    MessageDigest sha = MessageDigest.getInstance("SHA-256");
    initkey =  sha.digest(initkey);
    initkey = Arrays.copyOf(initkey, 16);

    SecretKeySpec secretKeySpec =  new SecretKeySpec(initkey,"AES");

    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);



}

正如您所看到的，我已经静态地编码了AES密钥和IV，但是希望在DH中生成的AES密钥被分配到这个类中

公共类AES{

static String IV = "AAAAAAAAAAAAAAAA";
static String initkey = "13B_0(wcXNGkHAR[";

public static byte[] encrypt(byte[] plainData, int offset, int length) throws Exception {


    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");//CBC
    SecretKeySpec key = new SecretKeySpec(initkey.getBytes("UTF-8"), "AES");

    cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(IV.getBytes("UTF-8")));
    return cipher.doFinal(plainData, offset, length);
}

public static byte[] decrypt(byte[] cipherSound, int offset, int length) throws Exception {

    Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");//CBC
    SecretKeySpec key = new SecretKeySpec(initkey.getBytes("UTF-8"), "AES");

    cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(IV.getBytes("UTF-8")));
    return cipher.doFinal(cipherSound, offset, length);
}

}

Answer 1

figure out how to take the key from DH class and declare in AES class that this is the key it must use to encrypt

请检查这个tutorial

然后你可以使用返回的秘密：

byte[] masterKey = aKeyAgree.generateSecret();
// maybe hash the master key too
SecretKeySpec key = new SecretKeySpec(masterKey, 0, 16, "AES");

但是，如果您有双向通信，则每个方向都需要随机IV键或不同的键（源于主控键）

其他提示：

I have two devices which communicate via IP/port connection establishing live voice encrypting communication

也许你的设备足够强大，可以建立适当的TLS，什么能为你解决很多问题