如何将Diffie-Hellman类中生成的AES密钥添加到使用密钥的类中

Question

背景：我有两个设备通过IP /端口连接进行通信，这要归功于Diffie-Hellman密钥交换，并通过AES算法对实时语音加密通信进行加密。现在，已编写了一些代码，而有些仅用作原型实现的示例。

问题：现在，即使理解我的类的工作方式就像标题所述：我不知道如何从DH类中获取密钥并在AES类中声明这是加密所必须使用的密钥。

P.s。欢迎提供有关代码优化，更好的做法和一般提示的建议。谢谢您的时间。

公共类DH扩展了线程{

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);



}

如您所见，我已经静态地对AES密钥和IV进行了编码，但是希望在此类中分配DH中生成的AES密钥

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

弄清楚如何从DH类中获取密钥并在AES类中声明这是必须用于加密的密钥

请检查此tutorial

然后您可以使用返回的机密：

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

但是，如果您使用双向通信，则每个方向都需要随机IV或不同的键（从主机获取）

附加提示：

我有两个通过IP /端口连接进行通信以建立实时语音加密通信的设备

也许您的设备足够强大，可以建立适当的TLS，这将为您解决很多问题