帮我写一段无需使用相关库的带输出的NTRU数字签名的java语言代码

好的，以下是一份基于NTRU数字签名的简单Java代码，无需使用相关库：

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;

public class NTRU {

    private static final int MESSAGE_LENGTH = 64; // 消息长度
    private static final int N = 503; // NTRU公共参数，不用更改
    private static final int P = 3; // NTRU公共参数，不用更改
    private static final int Q = 101; // NTRU公共参数，不用更改
    private static final int D = 97; // NTRU公共参数，不用更改
    private static final int DR = 90; // NTRU公共参数，不用更改

    private BigInteger s; // 加密密钥
    private BigInteger h; // 验证公钥
    private BigInteger f; // 签名私钥

    // 生成加密密钥、验证公钥和签名私钥
    public void generateKeyPair() {
        BigInteger t = generateT();
        BigInteger b = generateB(t);
        BigInteger a = createA(t, b);
        BigInteger c = createC(a, b);
        s = createS(c);
        h = createH(a, b);
        f = createF(t, c);
    }

    // 对消息进行签名
    public BigInteger sign(byte[] message) {
        BigInteger m = new BigInteger(1, message);
        BigInteger e = createE(m);
        BigInteger u = createU(e);
        return u;
    }

    // 验证签名是否合法
    public boolean verify(byte[] message, BigInteger u) {
        BigInteger m = new BigInteger(1, message);
        BigInteger v = createV(h, u);
        BigInteger e = createE(m);
        BigInteger t = createT(v, e);        
        return t.equals(u.modPow(f, BigInteger.valueOf(Q)));
    }

    // 生成NTT变换参数t
    private BigInteger generateT() {
        Random random = new Random();
        BigInteger t = BigInteger.valueOf(random.nextInt((int) Math.pow(2, DR - 1)));
        return t.setBit(DR - 1).setBit(0).setBit(N);
    }

    // 生成多项式b
    private BigInteger generateB(BigInteger t) {
        BigInteger b;
        do {
            b = new BigInteger(N, new Random());
            b = b.setBit(N - 1).setBit(P - 1).setBit(0);
        } while (t.gcd(b).intValue() != 1);
        return b;
    }

    // 生成多项式a
    private BigInteger createA(BigInteger t, BigInteger b) {
        BigInteger a = t.divide(b);
        return a;
    }

    // 生成多项式c
    private BigInteger createC(BigInteger a, BigInteger b) {
        Random random = new Random();
        BigInteger c = new BigInteger(N, random);
        c = c.setBit(N - 1).setBit(P).setBit(0);
        return c.subtract(a.multiply(b));
    }

    // 生成加密密钥s
    private BigInteger createS(BigInteger c) {
        return c.modPow(BigInteger.valueOf(D), BigInteger.valueOf(Q));
    }

    // 生成验证公钥h
    private BigInteger createH(BigInteger a, BigInteger b) {
        return b.modInverse(BigInteger.valueOf(Q)).multiply(a).mod(BigInteger.valueOf(Q));
    }

    // 生成签名私钥f
    private BigInteger createF(BigInteger t, BigInteger c) {
        return t.multiply(c.modInverse(BigInteger.valueOf(Q))).mod(BigInteger.valueOf(Q-1));
    }

    // 计算多项式e
    private BigInteger createE(BigInteger m) {
        byte[] hashedMessage = sha256(m.toByteArray());
        BigInteger e = new BigInteger(1, hashedMessage).modPow(BigInteger.valueOf(2), BigInteger.valueOf(Q));
        return e;
    }

    // 计算多项式u
    private BigInteger createU(BigInteger e) {
        BigInteger u = e.multiply(s).mod(BigInteger.valueOf(Q));
        return u;
    }

    // 计算多项式v
    private BigInteger createV(BigInteger h, BigInteger u) {
        BigInteger v = u.mod(h).modPow(BigInteger.valueOf(D), BigInteger.valueOf(Q));
        return v;
    }

    // 计算t
    private BigInteger createT(BigInteger v, BigInteger e) {
        BigInteger t = v.modPow(e, BigInteger.valueOf(Q));
        return t;
    }

    // SHA-256散列函数
    private static byte[] sha256(byte[] message) {
        try {
            MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
            sha256.update(message);
            return sha256.digest();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        NTRU ntru = new NTRU();
        ntru.generateKeyPair();

        byte[] message = "Hello, world!".getBytes();
        BigInteger signature = ntru.sign(message);
        boolean valid = ntru.verify(message, signature);

        System.out.println("Valid signature: " + valid);
    }
}

请注意：这仅仅是一个非常简单的示例，实际运用中需要更复杂的实现。此外，对于严格安全性的要求，建议使用专业的库函数实现。