Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.KeyFactory;

import java.security.PublicKey;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.X509EncodedKeySpec;
import org.apache.commons.codec.binary.Base64;

public class Main {
    static String public_key = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC+mAHzzAOTyDeLqVGRbSe/Ys2dA0K0PYzs7VkhUcSczJEckLEqzjVWapmQ7XSXnONnOOA7LVzYLvvRc/3d0EK3gq1sF39JMKUpeaaI+OAuE3UVRLIxnmmMJBTkAGqSQuOhuG7qJstDCg49W3KeMc8ZXXg7T4TjRWr3Hg9VbH+RIwIDAQAB";

    public static BigInteger computeUnblindSignature(BigInteger r, BigInteger bs)
            throws UnsupportedEncodingException {
        RSAPublicKey pubKey = (RSAPublicKey) getPublicKey(public_key);
        BigInteger n = pubKey.getModulus();

        BigInteger s = r.modInverse(n).multiply(bs).mod(n);

        return s;
    }

    public static PublicKey getPublicKey(String key) {
        try {
            Base64 base64_decoder = new Base64();
            byte[] byteKey = base64_decoder.decode(key.getBytes()); // ,
            // Base64.DEFAULT);
            X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey);
            KeyFactory kf = KeyFactory.getInstance("RSA");

            return kf.generatePublic(X509publicKey);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}