Как зашифровать двойное / число с плавающей запятой (не целое число) в криптосистеме Paillier Java?

Question

Я пытаюсь использовать homomomrphic в криптосистеме Paillier, но когда я хочу зашифровать двойное число / число с плавающей запятой, его ошибка, потому что я использую BigInteger в Java для шифрования и дешифрования. и этот код я получаю в gitHub

импорт java.math. ; импорт java.util.;

public class paillier {
private BigInteger p,  q,  lambda;
/**
 * n = p*q, where p and q are two large primes.
 */
public BigInteger n;
/**
 * nsquare = n*n
 */
public BigInteger nsquare;
/**
 * a random integer in Z*_{n^2} where gcd (L(g^lambda mod n^2), n) = 1.
 */
private BigInteger g;
/**
 * number of bits of modulus
 */
private int bitLength;

/**
 * Constructs an instance of the Paillier cryptosystem.
 * @param bitLengthVal number of bits of modulus
 * @param certainty The probability that the new BigInteger represents a prime number will exceed (1 - 2^(-certainty)). The execution time of this constructor is proportional to the value of this parameter.
 */
public paillier(int bitLengthVal, int certainty) {
    KeyGeneration(bitLengthVal, certainty);
}

/**
 * Constructs an instance of the Paillier cryptosystem with 512 bits of modulus and at least 1-2^(-64) certainty of primes generation.
 */
public paillier() {
    KeyGeneration(1024, 64);
}

/**
 * Sets up the public key and private key.
 * @param bitLengthVal number of bits of modulus.
 * @param certainty The probability that the new BigInteger represents a prime number will exceed (1 - 2^(-certainty)). The execution time of this constructor is proportional to the value of this parameter.
 */
public void KeyGeneration(int bitLengthVal, int certainty) {
    bitLength = bitLengthVal;
    /*Constructs two randomly generated positive BigIntegers that are probably prime, with the specified bitLength and certainty.*/
    p = new BigInteger(bitLength / 2, certainty, new Random());
    q = new BigInteger(bitLength / 2, certainty, new Random());

    n = p.multiply(q);
    nsquare = n.multiply(n);

    g = new BigInteger("2");
    lambda = p.subtract(BigInteger.ONE).multiply(q.subtract(BigInteger.ONE)).divide(
            p.subtract(BigInteger.ONE).gcd(q.subtract(BigInteger.ONE)));
    /* check whether g is good.*/
    if (g.modPow(lambda, nsquare).subtract(BigInteger.ONE).divide(n).gcd(n).intValue() != 1) {
        System.out.println("g is not good. Choose g again.");
        System.exit(1);
    }
}

/**
 * Encrypts plaintext m. ciphertext c = g^m * r^n mod n^2. This function explicitly requires random input r to help with encryption.
 * @param m plaintext as a BigInteger
 * @param r random plaintext to help with encryption
 * @return ciphertext as a BigInteger
 */
public BigInteger Encryption(BigInteger m, BigInteger r) {
    return g.modPow(m, nsquare).multiply(r.modPow(n, nsquare)).mod(nsquare);
}

/**
 * Encrypts plaintext m. ciphertext c = g^m * r^n mod n^2. This function automatically generates random input r (to help with encryption).
 * @param m plaintext as a BigInteger
 * @return ciphertext as a BigInteger
 */
public BigInteger Encryption(BigInteger m) {
    BigInteger r = new BigInteger(bitLength, new Random());
    return g.modPow(m, nsquare).multiply(r.modPow(n, nsquare)).mod(nsquare);

}

/**
 * Decrypts ciphertext c. plaintext m = L(c^lambda mod n^2) * u mod n, where u = (L(g^lambda mod n^2))^(-1) mod n.
 * @param c ciphertext as a BigInteger
 * @return plaintext as a BigInteger
 */
public BigInteger Decryption(BigInteger c) {
    //BigInteger u = g.modPow(lambda, nsquare).subtract(BigInteger.ONE).divide(n).modInverse(n);
    BigInteger u = g.modPow(lambda, nsquare).subtract(BigInteger.ONE).divide(n).modInverse(n);
    return c.modPow(lambda, nsquare).subtract(BigInteger.ONE).divide(n).multiply(u).mod(n);
}

/**
 * main function
 * @param str intput string
 */
public static void main(String[] str) {
    /* instantiating an object of Paillier cryptosystem*/
    paillier paillier = new paillier();
    /* instantiating two plaintext msgs*/
    BigInteger m1 = new BigInteger("60");
    BigInteger m2 = new BigInteger("20");

    /* encryption*/
    BigInteger em1 = paillier.Encryption(m1);
    BigInteger em2 = paillier.Encryption(m2);
    /* printout encrypted text*/
    System.out.println("Encrypted m1 : "+em1);
    System.out.println("Encrypted m2 : "+em2);
    /* printout decrypted text */
    System.out.println("Decrypted em1 : "+paillier.Decryption(em1).toString());
    System.out.println("Decrypted em2 : "+paillier.Decryption(em2).toString());

    /* test homomorphic properties -> D(E(m1)*E(m2) mod n^2) = (m1 + m2) mod n */
    BigInteger product_em1em2 = em1.multiply(em2).mod(paillier.nsquare);
    BigInteger sum_m1m2 = m1.add(m2).mod(paillier.n);

    System.out.println("original sum: " + sum_m1m2.toString());
    System.out.println("decrypted sum: " + paillier.Decryption(product_em1em2).toString());

    /* test homomorphic properties -> D(E(m1)^m2 mod n^2) = (m1*m2) mod n */
    BigInteger expo_em1m2 = em1.modPow(m2, paillier.nsquare);
    BigInteger prod_m1m2 = m1.multiply(m2).mod(paillier.n);
    System.out.println("original product: " + prod_m1m2.toString());
    System.out.println("decrypted product: " + paillier.Decryption(expo_em1m2).toString());

}

}

Может кто-нибудь помочь мне решить мою проблему?