generate RSA Private Key - Java Security

Java examples for Security:RSA

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Description

generate RSA Private Key

Demo Code


import java.io.ByteArrayOutputStream;
import java.math.BigInteger;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;

public class Main{
    //w  w w .  ja  v  a2 s . c o  m
    public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus,
            byte[] privateExponent) throws Exception {
        KeyFactory keyFac = null;
        try {
            keyFac = KeyFactory
                    .getInstance(
                            "RSA",
                            new org.bouncycastle.jce.provider.BouncyCastleProvider());
        } catch (NoSuchAlgorithmException ex) {
            throw new Exception(ex.getMessage());
        }

        RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(
                new BigInteger(modulus), new BigInteger(privateExponent));
        try {
            return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
        } catch (InvalidKeySpecException ex) {
            throw new Exception(ex.getMessage());
        }
    }
    
    public static RSAPrivateKey generateRSAPrivateKey(String modulus,
            String privateExponent) throws Exception {
        KeyFactory keyFac = null;
        try {
            keyFac = KeyFactory
                    .getInstance(
                            "RSA",
                            new org.bouncycastle.jce.provider.BouncyCastleProvider());
        } catch (NoSuchAlgorithmException ex) {
            throw new Exception(ex.getMessage());
        }

        RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(
                new BigInteger(modulus, 16), new BigInteger(
                        privateExponent, 16));
        try {
            return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
        } catch (InvalidKeySpecException ex) {
            throw new Exception(ex.getMessage());
        }
    }
}

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