Develop Reference

0auth_signature using SHA1-RSA in java

In have integrated oauth1.0. i am using sha1-rsa signature method. i have generated oauth signature. i got 200 status but i did not get any value in service provider. my doubt is signature generation. how to generate the oauth signature using sha1-rsa in java? i have mentioned link what am using.
`private static KeyPair getKeyPair() throws NoSuchAlgorithmException {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024, new SecureRandom());
return kpg.genKeyPair();
}`
public static String sign(PrivateKey privateKey) throws Exception {
Signature privateSignature = Signature.getInstance(" ");
privateSignature.initSign(privateKey);
//privateSignature.update(plainText.getBytes(UTF_8));
byte[] signature = privateSignature.sign();
System.out.println(Base64.encodeBase64String(signature));
return Base64.encodeBase64String(signature);
//encodeToString(signature);
}
thanks in advance,

Below snippets generate a valid signature, i.e. signs the input data using an RSA Private Key string i.e. creates a private key from contents of a .pkcs8 private key file. This is in Groovy (works with Java with minimal syntax changes:
import java.security.SignatureException;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.Signature;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
//-------- generate RSA-SHA1 signature from request data
def encryptUsingRSASHA1(String data, String key) throws
java.security.SignatureException
{
String result
try {
// get an rsa_sha1 key from the raw key bytes
//SHA1withRSA
Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(getPrivateKey(key));
signature.update(data.getBytes("UTF-8"));
byte[] rawRSAsigned = signature.sign();
result= rawRSAsigned.encodeBase64()
} catch (Exception e) {
throw new SignatureException("Failed to generate Signature : " +
e.getMessage());
}
return result
}
//get PrivateKey from key string
def getPrivateKey(String privateKey) throws NoSuchAlgorithmException,
InvalidKeySpecException {
String privateKeyPEM = privateKey.replace("-----BEGIN PRIVATE KEY-----\n",
"").replace("-----END PRIVATE KEY-----", "").replaceAll("\n","");
byte[] privateKeyBytes = privateKeyPEM.decodeBase64();
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePrivate(keySpec);
}

Is there anyway to encrypt and decrypt a message using Elliptic Curve (EC) Public Key and Private Key using Java

Is there anyway to encrypt and decrypt a message using Elliptic Curve (EC) Public Key and Private Key using Java?
I was trying to encrypt a message using Elliptic Curve (EC) public key and decrypt it using Elliptic Curve (EC) private key but I keep getting error:
java.security.NoSuchAlgorithmException: Cannot find any provider supporting EC
at javax.crypto.Cipher.getInstance(Cipher.java:539)
at encryptanddecrypt.EncryptAndDecrypt.encrypt(EncryptAndDecrypt.java:87)
at encryptanddecrypt.EncryptAndDecrypt.main(EncryptAndDecrypt.java:48)
BUILD SUCCESSFUL (total time: 0 seconds)
I have try google it but all failed because most of the solution use Encryption and Decryption message using RSA. Can someone help me and advice me what could be the issue over here?
package encryptanddecrypt;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.xml.bind.DatatypeConverter;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class EncryptAndDecrypt {
private static final String ALGORITHM = "EC";
public static void main(String[] args) {
// TODO code application logic here
try{
String publicKeyPem="-----BEGIN PUBLIC KEY-----\n" +
"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEQrkzEdm2ClPnfouyeFkCDsjtRC/x\n" +
"Iaja7F0RbXn3/qKcYQMinaMIs17OhcJQpxasAi1GAPPqc3yF35ngnrj7Kg==\n" +
"-----END PUBLIC KEY-----";
String privateKeyPem="-----BEGIN EC PRIVATE KEY-----\n" +
"MHcCAQEEIE3Z7wMD6/dzQ7eij9xHq6PmyJF53Gk91HjYU2RoZgS7oAoGCCqGSM49\n" +
"AwEHoUQDQgAEQrkzEdm2ClPnfouyeFkCDsjtRC/xIaja7F0RbXn3/qKcYQMinaMI\n" +
"s17OhcJQpxasAi1GAPPqc3yF35ngnrj7Kg==\n" +
"-----END EC PRIVATE KEY-----";
byte[] publicKey = convertPublicPem(publicKeyPem);
byte[] privateKey = convertPrivatePem(privateKeyPem);
byte[] encryptedData = encrypt(publicKey,"Hi Lingkesh Here".getBytes());
byte[] decryptedData = decrypt(privateKey, encryptedData);
System.out.println(new String(decryptedData));
}catch(Exception e){
e.printStackTrace();
}
}
public static byte[] convertPublicPem(String PUBLIC_KEY_STRING){
String publicKeyPEM = PUBLIC_KEY_STRING
.replace("-----BEGIN PUBLIC KEY-----", "")
.replaceAll(System.lineSeparator(), "")
.replace("-----END PUBLIC KEY-----", "");
byte[] bytes = DatatypeConverter.parseBase64Binary(publicKeyPEM);
System.out.println(Arrays.toString(bytes));
return bytes;
}
public static byte[] convertPrivatePem(String PRIVATE_KEY_STRING){
String privateKeyPEM = PRIVATE_KEY_STRING
.replace("-----BEGIN EC PRIVATE KEY-----", "")
.replaceAll(System.lineSeparator(), "")
.replace("-----END EC PRIVATE KEY-----", "");
byte[] bytes = DatatypeConverter.parseBase64Binary(privateKeyPEM);
System.out.println(Arrays.toString(bytes));
return bytes;
}
public static byte[] encrypt(byte[] publicKey, byte[] inputData)
throws Exception {
PublicKey key = KeyFactory.getInstance(ALGORITHM)
.generatePublic(new X509EncodedKeySpec(publicKey));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encryptedBytes = cipher.doFinal(inputData);
return encryptedBytes;
}
public static byte[] decrypt(byte[] privateKey, byte[] inputData)
throws Exception {
PrivateKey key = KeyFactory.getInstance(ALGORITHM)
.generatePrivate(new PKCS8EncodedKeySpec(privateKey));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decryptedBytes = cipher.doFinal(inputData);
return decryptedBytes;
}
public static KeyPair generateKeyPair()
throws NoSuchAlgorithmException, NoSuchProviderException {
KeyPairGenerator keyGen = KeyPairGenerator.getInstance(ALGORITHM);
SecureRandom random = SecureRandom.getInstance("SHA256PRNG", "SUN");
keyGen.initialize(256, random);
KeyPair generateKeyPair = keyGen.generateKeyPair();
return generateKeyPair;
}
}

Fail to match SHA256withRSA signature from Java on .Net c#

I have some code in Java that successfully verifies and sign messages with SHA256withRSA. However when I try to verify the same data with my c# code, I get a different signature and verification of the signature fails. As the SHA values match, i figure it not related to codepage. I tried multiple ways to figure this one out, but is yet to fail, so any ideas is more than welcome.
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.spec.X509EncodedKeySpec;
import java.io.*;
import java.util.*;
import java.security.*;
import java.util.Base64;
import java.lang.*;
import java.nio.charset.*;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMException;
import org.bouncycastle.openssl.PEMKeyPair;
import org.bouncycastle.openssl.PEMParser;
import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
public class Main {
public static void main(String[] args) throws Exception {
String privatePem = "c:\\Lab\\Cert\\private.pem";
String publicPem = "C:\\Lab\\Cert\\public.pem";
String datafile = "C:\\Lab\\Cert\\data.txt";
byte[] buf = Files.readAllBytes(Paths.get(datafile));
String message = new String(buf, StandardCharsets.UTF_8);
System.out.println("-----------------------------------------------------------------------------------------------------------------------------------------");
System.out.println("Message to sign:");
System.out.println(message);
System.out.println("-----------------------------------------------------------------------------------------------------------------------------------------");
PrivateKey privateKey = PrivateKeyReader(privatePem).getPrivate();
PublicKey publicKey = get(publicPem);
// Get SHA-256
byte[] messageAsByte = message.getBytes(Charset.forName( "UTF-8" ));
byte[] sha256OfMessage = digestSha256(messageAsByte);
byte[] sha512OfMessage = digestSha512(messageAsByte);
byte[] base64encodedSha256 = Base64.getEncoder().encode(sha256OfMessage);
byte[] base64encodedSha512 = Base64.getEncoder().encode(sha512OfMessage);
String Sha256ContentDigest = new String(base64encodedSha256, StandardCharsets.UTF_8);
String Sha512ContentDigest = new String(base64encodedSha512, StandardCharsets.UTF_8);
byte[] signature256 = generateSignature256(messageAsByte, privateKey);
String sig25664 = Base64.getEncoder().encodeToString(signature256);
System.out.println("X-Content-Digest: SHA256 " + Sha256ContentDigest);
System.out.println("X-Signature: RSA-SHA256 " + sig25664);
System.out.println("-----------------------------------------------------------------------------------------------------------------------------------------");
byte[] signature512 = generateSignature512(messageAsByte, privateKey);
String sig51264 = Base64.getEncoder().encodeToString(signature512);
System.out.println("X-Content-Digest: SHA512 " + Sha512ContentDigest);
System.out.println("X-Signature: RSA-SHA512 " + sig51264);
System.out.println("-----------------------------------------------------------------------------------------------------------------------------------------");
System.out.println("Signature verification SHA256: " + verifySignature256(messageAsByte, sha256OfMessage, signature256, publicKey));
System.out.println("Signature verification SHA512: " + verifySignature512(messageAsByte, sha512OfMessage, signature512, publicKey));
System.out.println("-----------------------------------------------------------------------------------------------------------------------------------------");
}
private static KeyPair PrivateKeyReader(String keyPath) {
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(keyPath));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Security.addProvider(new BouncyCastleProvider());
PEMParser pp = new PEMParser(br);
PEMKeyPair pemKeyPair = null;
try {
pemKeyPair = (PEMKeyPair) pp.readObject();
} catch (IOException e) {
e.printStackTrace();
}
try {
KeyPair kp = new JcaPEMKeyConverter().getKeyPair(pemKeyPair);
return kp;
} catch (PEMException e) {
e.printStackTrace();
}
try {
pp.close();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
public static byte[] generateSignature256(byte[] requestMessage, PrivateKey privateKey) throws Exception {
byte[] contentDigest = digestSha256(requestMessage);
Signature signature = Signature.getInstance("Sha256withRSA");
signature.initSign(privateKey);
signature.update(contentDigest);
return signature.sign();
}
public static byte[] generateSignature512(byte[] requestMessage, PrivateKey privateKey) throws Exception {
byte[] contentDigest = digestSha512(requestMessage);
Signature signature = Signature.getInstance("Sha512withRSA");
signature.initSign(privateKey);
signature.update(contentDigest);
return signature.sign();
}
public static boolean verifySignature256(byte[] requestMessage, byte[] requestContentDigest, byte[] requestSignature, PublicKey publicKey) throws Exception {
byte[] contentDigest = digestSha256(requestMessage);
if (!Arrays.equals(requestContentDigest, contentDigest)) {
return false;
}
Signature signature = Signature.getInstance("Sha256withRSA");
signature.initVerify(publicKey);
signature.update(contentDigest);
return signature.verify(requestSignature);
}
public static boolean verifySignature512(byte[] requestMessage, byte[] requestContentDigest, byte[] requestSignature, PublicKey publicKey) throws Exception {
byte[] contentDigest = digestSha512(requestMessage);
if (!Arrays.equals(requestContentDigest, contentDigest)) {
return false;
}
Signature signature = Signature.getInstance("Sha512withRSA");
signature.initVerify(publicKey);
signature.update(contentDigest);
return signature.verify(requestSignature);
}
public static byte[] digestSha256(byte[] requestMessage){
try {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
return digest.digest(requestMessage);
} catch (Exception e){
return null;
}
}
public static byte[] digestSha512(byte[] requestMessage){
try {
MessageDigest digest = MessageDigest.getInstance("SHA-512");
return digest.digest(requestMessage);
} catch (Exception e){
return null;
}
}
public static PublicKey get(String keyPath)
throws Exception {
Reader reader = new FileReader(keyPath);
PublicKey key;
try {
org.bouncycastle.util.io.pem.PemObject spki = new org.bouncycastle.util.io.pem.PemReader(reader).readPemObject();
key = KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(spki.getContent()));
} catch (Exception ex) {
FileInputStream fin = new FileInputStream(keyPath);
CertificateFactory f = CertificateFactory.getInstance("X.509");
X509Certificate certificate = (X509Certificate)f.generateCertificate(fin);
key = certificate.getPublicKey();
}
return key;
}
}
Output:
-----------------------------------------------------------------------------------------------------------------------------------------
Message to sign:
abc123
-----------------------------------------------------------------------------------------------------------------------------------------
X-Content-Digest: SHA256 bKE9UspwyIPg8LsQHkJaiehiTeUdstI5JZOvaoQRgJA=
X-Signature: RSA-SHA256 H9DF4NYV9YOZ3B3iogDIdlTzzQpKGWniQNHF5ZxladLes0MDcFopUSzyO6XiO1Y/AVBGLK18iq2nCc8ho+fXb6c4V08/PSE4lrGJu7z8dAs9UwodDgAx3+TXBV8iNkGtj3XThy7QhvruPA0txRLgdaRmKSJsBSoR7HK6LC0ES2LYzypQFXuQ+4LInWETPc4Ttp9bgSf/h07bZaQMlbO29hIQXZc31WCVTGmsJOG+TMBdF+CpWF04sj12ThR539VCpGrJRrE6xsYSg2VQMgo9t2XkcC/nn3Z4FOMD4o5yuwjHHJO1Hs4wyZfpSehIT96pYwvhkyMM5fS0Ms/Po9WUUg==
-----------------------------------------------------------------------------------------------------------------------------------------
X-Content-Digest: SHA512 xwtd2ev7b1HQnUEytxcMnSB1CnhS8AaA9lZY8DEOgQBW5nY8NMmgCw6UAHb1RJXBafwjAszrMSA5JxxDRpUH3A==
X-Signature: RSA-SHA512 UT0UlWI06+pYg+OuJGCaoIua23lq/k3yATkO9wQOl7BGLO56t7dvVZQz8UYtzIUhTrDktw9McqyTncDH8bZKMNMMCPLR7K3xAe3gCgipYE8VSP8uVeLDlqKhc/4OO+HDL6T6L44L1dwy5jKBVbVxDDKib7b0lLtTUtTHIh9WOX74hF6P3OiAZ8CD7tJg4QjngJ0GcM9WKXzfDNxVnOzGkhSarhCu3vsUP7QwG2um54uaADgqcJoJvVVyhlwOPF4kPH8SaAPItUIbz46h4bpF182YFZ7QJeg8TmsqXeOdO2MPdKOPYQsPfwZVs/UFkl7Z0oC5WE9UX7Ds9B7/VkOudw==
-----------------------------------------------------------------------------------------------------------------------------------------
Signature verification SHA256: true
Signature verification SHA512: true
-----------------------------------------------------------------------------------------------------------------------------------------
.Net C# code attempt:
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.OpenSsl;
using Org.BouncyCastle.Security;
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace VAS
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("-----------------------------------------------------------------------------------------------------------------------------------------");
byte[] messageAsByte = File.ReadAllBytes(#"C:\Lab\Cert\data.txt");
Console.WriteLine("Message to sign:");
Console.WriteLine(Encoding.UTF8.GetString(messageAsByte));
Console.WriteLine("-----------------------------------------------------------------------------------------------------------------------------------------");
var publicKey = LoadPublicKey(#"C:\Lab\Cert\public.pem");
var privateKey = LoadPrivateKey(#"C:\Lab\Cert\private.pem");
var sha256OfMessage = digestSha256(messageAsByte);
var sha512OfMessage = digestSha512(messageAsByte);
string Sha256ContentDigest = Convert.ToBase64String(sha256OfMessage);
string Sha512ContentDigest = Convert.ToBase64String(sha512OfMessage);
HashAlgorithm hash256Algorith = SHA256Managed.Create();
HashAlgorithm hash512Algorith = SHA256Managed.Create();
byte[] sig256 = privateKey.SignData(messageAsByte, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
byte[] sig512 = privateKey.SignData(messageAsByte, HashAlgorithmName.SHA512, RSASignaturePadding.Pkcs1);
var sig64256 = Convert.ToBase64String(sig256);
var sig64512 = Convert.ToBase64String(sig512);
Console.WriteLine("X-Content-Digest: SHA256 " + Sha256ContentDigest);
Console.WriteLine("X-Signature: RSA-SHA256 " + sig64256);
Console.WriteLine("-----------------------------------------------------------------------------------------------------------------------------------------");
Console.WriteLine("X-Content-Digest: SHA512 " + Sha512ContentDigest);
Console.WriteLine("X-Signature: RSA-SHA512 " + sig64512);
Console.WriteLine("-----------------------------------------------------------------------------------------------------------------------------------------");
var verify256 = publicKey.VerifyData(messageAsByte, CryptoConfig.MapNameToOID("SHA256"), sig256);
var verify512 = publicKey.VerifyData(messageAsByte, CryptoConfig.MapNameToOID("SHA512"), sig512);
Console.WriteLine("Signature verify 256: " + verify256);
Console.WriteLine("Signature verify 512: " + verify512);
Console.ReadKey();
}
public static RSACryptoServiceProvider LoadPublicKey(String path)
{
System.IO.StreamReader fileStream = File.OpenText(path);
PemReader pemReader = new PemReader(fileStream);
AsymmetricKeyParameter KeyParameter = (AsymmetricKeyParameter)pemReader.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaKeyParameters)KeyParameter);
RSACryptoServiceProvider csp = new RSACryptoServiceProvider();// cspParams);
csp.ImportParameters(rsaParams);
return csp;
}
public static RSACryptoServiceProvider LoadPrivateKey(String path)
{
System.IO.StreamReader fileStream = File.OpenText(path);
PemReader pemReader = new PemReader(fileStream);
AsymmetricCipherKeyPair KeyParameter = (AsymmetricCipherKeyPair)pemReader.ReadObject();
RSAParameters rsaParams = DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)KeyParameter.Private);
RSACryptoServiceProvider csp = new RSACryptoServiceProvider();// cspParams);
csp.ImportParameters(rsaParams);
return csp;
}
public static byte[] digestSha256(byte[] requestMessage)
{
SHA256Managed shHash = new SHA256Managed();
return shHash.ComputeHash(requestMessage);
}
public static byte[] digestSha512(byte[] requestMessage)
{
SHA512Managed shHash = new SHA512Managed();
return shHash.ComputeHash(requestMessage);
}
}
}
Output:
-----------------------------------------------------------------------------------------------------------------------------------------
Message to sign:
abc123
-----------------------------------------------------------------------------------------------------------------------------------------
X-Content-Digest: SHA256 bKE9UspwyIPg8LsQHkJaiehiTeUdstI5JZOvaoQRgJA=
X-Signature: RSA-SHA256 Wo0dFOfzAJJZTb4zpOHkPVdpgWS1K2Q5IdAAD1wQ+w1veAIbmu+XByBHAbme0PiazdqF6QokFm9IudF7NmyqNjNybIKSuTRPUiP474/kliQl7lDiJJoFejBIaVwQhHdds0CkomZZPulZZSYuIi7cqODaKCXxe/Js9tm/htMu3Wd6nejgaoMX3TGXHWyE6ixJI8Zq7ysD6yjksIWlYthsd0WmCR6mVTKR9zo7BiVPxYsOcJ7MFLSvyJgHHoFmXG9KBZhcA1rx8RquvWLGKxU+WWbt7u/9OqY+HKGPCPo2/S1xmdTP2kiVp1zhQ0JQ4uBgP9nkNqrBxh3QzSZgsCbJKg==
-----------------------------------------------------------------------------------------------------------------------------------------
X-Content-Digest: SHA512 xwtd2ev7b1HQnUEytxcMnSB1CnhS8AaA9lZY8DEOgQBW5nY8NMmgCw6UAHb1RJXBafwjAszrMSA5JxxDRpUH3A==
X-Signature: RSA-SHA512 V47yMVpBunwkUVz0lmi5ZJkYkj2+C9V3YX1MB7OaDvobCGc9F0vBoEsxsV0sDIR2gZsHVMowXFU2bHzIoNdeGz+iyichQ89fJXYP+qPQUZO42t0UXfefX/9LlMbkGlzOqFvfBkcOFidhF9x36ZGPcC6C9AjOC7r1sqL/IBxNENuknhcbBMzHHpJZXFzVo09U/p7LIs3kJxAE9TLkR4ir2syAfisKrbJYCTSZnwm38ikR35mMmigme8eByE6GuOmizshv7lrtd4K5d0RA1jWM1TrNKpLqil4IWbrYQXZCBnHUmLH4fTD7aGIpM+SxQXLBV/lDhWA3O8vXDdFnW0llxQ==
-----------------------------------------------------------------------------------------------------------------------------------------
Signature verify 256: True
Signature verify 512: True
Testkeys and data
private.pem:
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
public.pem:
-----BEGIN PUBLIC KEY-----
MIIBITANBgkqhkiG9w0BAQEFAAOCAQ4AMIIBCQKCAQBk04fDxgG0eV/b7wcTYK7k
q72w4YMzlPyBy6hERHWD2DhuM6TQMF7cafxc4b8krGMBqgV9m7AQxhWn4GCmCHlj
acXivTc1qBp3S54IitZFqvyGhnC0dqKshqaL6z/S1kbiPZmiiXpZScYkje5pxY7k
11PTopqnV9/g89Cu+PDEd7KcA0XEXbYaEZtufvahZBmbF5mQPAr5YwGDgrR16CiA
Gi3dcWqX7g7AJb6bSJQp1SEWYVHUklSdOtIJPgTDB57VIC8klKJ0c2Lnn3M+qPl6
aD0qLTyl2QH1q97G+7E0e2dYAAbXj0uU8753iEE/nHeOz09ACkIdLw9e97Kmka4D
AgMBAAE=
-----END PUBLIC KEY-----
data.txt:
abc123
I also tried signing with OpenSSL, and that gives the same result i get with C#. Any help would be appricated so I can handle the data that is generated in Java.
Thanks!

The difference is in handling the hash. In .NET you are handling it correctly:
byte[] sig256 = privateKey.SignData(messageAsByte, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
however in Java, for some reason, you are feeding a precomputed hash value instead of the data:
byte[] contentDigest = digestSha256(requestMessage);
...
signature.update(contentDigest);
In other words, your data is hashed, and then the hash over the data is hashed.
Remember that signature generation in general includes the hashing of the data. Sometimes you can feed a precomputed hash value into the signature generation / verification, but commonly you'll have to call a specifically named method for that, calls such as update are for the message data itself.
Both .NET and Java use PKCS#1 v1.5 padding in your code snippets. PKCS#1 v1.5 padding for signature generation is indeed deterministic and considered secure. PSS is a newer, non-deterministic and more secure method and should be preferred for new protocols & applications.
As a small bonus, here is some code for testing:
private static final String PUB_BASE_64 = "MIIBITANBgkqhkiG9w0BAQEFAAOCAQ4AMIIBCQKCAQBk04fDxgG0eV/b7wcTYK7k" +
"q72w4YMzlPyBy6hERHWD2DhuM6TQMF7cafxc4b8krGMBqgV9m7AQxhWn4GCmCHlj" +
"acXivTc1qBp3S54IitZFqvyGhnC0dqKshqaL6z/S1kbiPZmiiXpZScYkje5pxY7k" +
"11PTopqnV9/g89Cu+PDEd7KcA0XEXbYaEZtufvahZBmbF5mQPAr5YwGDgrR16CiA" +
"Gi3dcWqX7g7AJb6bSJQp1SEWYVHUklSdOtIJPgTDB57VIC8klKJ0c2Lnn3M+qPl6" +
"aD0qLTyl2QH1q97G+7E0e2dYAAbXj0uU8753iEE/nHeOz09ACkIdLw9e97Kmka4D" +
"AgMBAAE=";
private static final String SIG_SHA256_DOTNET_BASE_64 = "Wo0dFOfzAJJZTb4zpOHkPVdpgWS1K2Q5IdAAD1wQ+w1veAIbmu+XByBHAbme0PiazdqF6QokFm9IudF7NmyqNjNybIKSuTRPUiP474/kliQl7lDiJJoFejBIaVwQhHdds0CkomZZPulZZSYuIi7cqODaKCXxe/Js9tm/htMu3Wd6nejgaoMX3TGXHWyE6ixJI8Zq7ysD6yjksIWlYthsd0WmCR6mVTKR9zo7BiVPxYsOcJ7MFLSvyJgHHoFmXG9KBZhcA1rx8RquvWLGKxU+WWbt7u/9OqY+HKGPCPo2/S1xmdTP2kiVp1zhQ0JQ4uBgP9nkNqrBxh3QzSZgsCbJKg==";
private static final String SIG_SHA256_JAVA_BASE_64 = "H9DF4NYV9YOZ3B3iogDIdlTzzQpKGWniQNHF5ZxladLes0MDcFopUSzyO6XiO1Y/AVBGLK18iq2nCc8ho+fXb6c4V08/PSE4lrGJu7z8dAs9UwodDgAx3+TXBV8iNkGtj3XThy7QhvruPA0txRLgdaRmKSJsBSoR7HK6LC0ES2LYzypQFXuQ+4LInWETPc4Ttp9bgSf/h07bZaQMlbO29hIQXZc31WCVTGmsJOG+TMBdF+CpWF04sj12ThR539VCpGrJRrE6xsYSg2VQMgo9t2XkcC/nn3Z4FOMD4o5yuwjHHJO1Hs4wyZfpSehIT96pYwvhkyMM5fS0Ms/Po9WUUg==";
public static void main(String[] args) throws Exception {
KeyFactory rsaKeyFactory = KeyFactory.getInstance("RSA");
PublicKey pub = rsaKeyFactory.generatePublic(new X509EncodedKeySpec(Base64.getDecoder().decode(PUB_BASE_64)));
Cipher rsa = Cipher.getInstance("RSA/ECB/NoPadding");
rsa.init(Cipher.DECRYPT_MODE, pub);
{
byte[] sig = Base64.getDecoder().decode(SIG_SHA256_JAVA_BASE_64);
byte[] plainSigJava = rsa.doFinal(sig);
System.out.println(Hex.toHexString(plainSigJava));
}
{
byte[] sig = Base64.getDecoder().decode(SIG_SHA256_DOTNET_BASE_64);
byte[] plainSigDotNet = rsa.doFinal(sig);
System.out.println(Hex.toHexString(plainSigDotNet));
}
byte[] hashSha256 = Base64.getDecoder().decode("bKE9UspwyIPg8LsQHkJaiehiTeUdstI5JZOvaoQRgJA=");
System.out.println(Hex.toHexString(hashSha256));
}
prints:
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
6ca13d52ca70c883e0f0bb101e425a89e8624de51db2d2392593af6a84118090
Note that the last signature "decryption" is the .NET one and contains the right hash value, printed on the final line.
Sorry, I used a non-standard Hex decoder, the rest is plain Java that you can put in a class definition.

Apple Pay Payment Token Decryption in Java

I am trying to decrypt the data field inside an Apple Pay Payment Token using ECC algorithm in Java on the server side. How can I implement it?
I've been searching for such an implementation in Java for quite a while and I couldn't find one. Instead, I've found an implementation using Bouncy Castle C# library to decrypt the token:
https://github.com/chengbo/ApplePayAndroidPayDecryption
Although there is also an Bouncy Castle library in Java, but I've found some difference in the implementation between the C# one and the Java one, which lead to the failure of decryption when I try to code in accordance with the C# implementation above.
I've generated my certificate in Apple Dev Center and I'm quite sure that the certificate file needed during the process of decrytion is correct.
Has anyone succeeded in decrypting the token in Java? Any help is appreciated, Thanks a lot!
Here is the key part of the return message from Apple when I did a test payment:
passKit={"version":"EC_v1","data":"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","signature":"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","header":{"ephemeralPublicKey":"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEFnF0WIB3GTpyaP7rgW0kzUMgqfwsTecb7/JrSQXZSuILCBPBs2YQQXFfIHNYtFFMzMTY24/tgbolbKjkmIUwIw==","applicationData":"5cd2d027aa6372ea5420770272ef47a596e60f4299c16c6591c3e7e532208394","publicKeyHash":"sRANn6djBkx5m//vTDU6HFOX4j1Nn/X4bNlgxJYRZgo=","transactionId":"947a5fc21adcc692bd204fa4e1a7a4f83ab8383283f3fa46b204b514559adede"}}

This Code(JAVA) will decrypt the ApplePay token. For this code to work convert the certificate file to JKS(retrieve merchant ID) and pk8(private key) formates.
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.bouncycastle.asn1.ASN1UTCTime;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.DERSet;
import org.bouncycastle.asn1.cms.CMSAttributes;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.SignerInformation;
import org.bouncycastle.cms.SignerInformationStore;
import org.bouncycastle.cms.jcajce.JcaSimpleSignerInfoVerifierBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.Store;
import org.bouncycastle.util.encoders.Hex;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import static org.bouncycastle.jce.provider.BouncyCastleProvider.PROVIDER_NAME;
import java.io.*;
import java.nio.charset.Charset;
import java.security.*;
import java.security.cert.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.*;
public class ApplePayDecrypt {
public static final String MERCHANT_ID = "merchant.Id";
private static KeyStore keyStore;
private static PrivateKey merchantPrivateKey;
static {
if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
Security.addProvider(new BouncyCastleProvider());
}
}
public static AppleDecryptData decrypt(TokenData tokenData) {
try {
// Load merchant private key
byte[] merchantbyte = IOUtils.toByteArray(Application.class.getResource("/apple_pay.pk8"));
String key = new String(merchantbyte);
key = key.replace("-----BEGIN PRIVATE KEY-----", "");
key = key.replace("-----END PRIVATE KEY-----", "");
key = key.replaceAll("\\s+", "");
byte[] merchantPrivateKeyBytes = Base64.decodeBase64(key);
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(merchantPrivateKeyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("EC", PROVIDER_NAME);
merchantPrivateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
// Load Apple root certificate
keyStore = KeyStore.getInstance("BKS");
keyStore.load(GoSecureApplication.class.getResourceAsStream("/appleCA-G3"), "apple123".toCharArray());
return unwrap(tokenData);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
#SuppressWarnings({ "unused", "unchecked" })
public static AppleDecryptData unwrap(TokenData tokenData) throws Exception {
// Merchants should use the 'version' field to determine how to verify and
// decrypt the message payload.
// At this time the only published version is 'EC_v1' which is demonstrated
// here.
String version = tokenData.version;
byte[] signatureBytes = Base64.decodeBase64(tokenData.signature);
byte[] dataBytes = Base64.decodeBase64(tokenData.data);
// JsonObject headerJsonObject =
// jsonObject.get(PAYMENT_HEADER).getAsJsonObject();
byte[] transactionIdBytes = Hex.decode(tokenData.header.transactionId);
byte[] ephemeralPublicKeyBytes = Base64.decodeBase64(tokenData.header.ephemeralPublicKey);
// Merchants that have more than one certificate may use the 'publicKeyHash'
// field to determine which
// certificate was used to encrypt this payload.
byte[] publicKeyHash = Base64.decodeBase64(tokenData.header.publicKeyHash);
// Application data is a conditional field, present when the merchant has
// supplied it to the iOS SDK.
byte[] applicationDataBytes = null;
byte[] signedBytes = ArrayUtils.addAll(ephemeralPublicKeyBytes, dataBytes);
signedBytes = ArrayUtils.addAll(signedBytes, transactionIdBytes);
signedBytes = ArrayUtils.addAll(signedBytes, applicationDataBytes);
CMSSignedData signedData = new CMSSignedData(new CMSProcessableByteArray(signedBytes), signatureBytes);
// Check certificate path
Store<?> certificateStore = signedData.getCertificates();
List<X509Certificate> certificates = new ArrayList<X509Certificate>();
JcaX509CertificateConverter certificateConverter = new JcaX509CertificateConverter();
certificateConverter.setProvider(PROVIDER_NAME);
for (Object o : certificateStore.getMatches(null)) {
X509CertificateHolder certificateHolder = (X509CertificateHolder) o;
certificates.add(certificateConverter.getCertificate(certificateHolder));
}
CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509", PROVIDER_NAME);
CertPath certificatePath = certificateFactory.generateCertPath(certificates);
PKIXParameters params = new PKIXParameters(keyStore);
params.setRevocationEnabled(false);
// TODO: Test certificate has no CRLs. Merchants must perform revocation checks
// in production.
// TODO: Verify certificate attributes per instructions at
// https://developer.apple.com/library/ios/documentation/PassKit/Reference/PaymentTokenJSON/PaymentTokenJSON.html#//apple_ref/doc/uid/TP40014929
CertPathValidator validator = CertPathValidator.getInstance("PKIX", PROVIDER_NAME);
PKIXCertPathValidatorResult result = (PKIXCertPathValidatorResult) validator.validate(certificatePath, params);
System.out.println(result);
// Verify signature
SignerInformationStore signerInformationStore = signedData.getSignerInfos();
boolean verified = false;
for (Object o : signerInformationStore.getSigners()) {
SignerInformation signer = (SignerInformation) o;
Collection<?> matches = certificateStore.getMatches(signer.getSID());
if (!matches.isEmpty()) {
X509CertificateHolder certificateHolder = (X509CertificateHolder) matches.iterator().next();
if (signer.verify(
new JcaSimpleSignerInfoVerifierBuilder().setProvider(PROVIDER_NAME).build(certificateHolder))) {
DERSequence sequence = (DERSequence) signer.getSignedAttributes().get(CMSAttributes.signingTime)
.toASN1Primitive();
DERSet set = (DERSet) sequence.getObjectAt(1);
ASN1UTCTime signingTime = (ASN1UTCTime) set.getObjectAt(0).toASN1Primitive();
// Merchants can check the signing time of this payment to determine its
// freshness.
System.out.println("Signature verified. Signing time is " + signingTime.getDate());
verified = true;
}
}
}
if (verified) {
// Ephemeral public key
KeyFactory keyFactory = KeyFactory.getInstance("EC", PROVIDER_NAME);
PublicKey ephemeralPublicKey = keyFactory.generatePublic(new X509EncodedKeySpec(ephemeralPublicKeyBytes));
// Key agreement
String asymmetricKeyInfo = "ECDH";
KeyAgreement agreement = KeyAgreement.getInstance(asymmetricKeyInfo, PROVIDER_NAME);
agreement.init(merchantPrivateKey);
agreement.doPhase(ephemeralPublicKey, true);
byte[] sharedSecret = agreement.generateSecret();
byte[] derivedSecret = performKDF(sharedSecret, extractMerchantIdFromCertificateOid());
// Decrypt the payment data
String symmetricKeyInfo = "AES/GCM/NoPadding";
Cipher cipher = Cipher.getInstance(symmetricKeyInfo, PROVIDER_NAME);
SecretKeySpec key = new SecretKeySpec(derivedSecret, cipher.getAlgorithm());
IvParameterSpec ivspec = new IvParameterSpec(new byte[16]);
cipher.init(Cipher.DECRYPT_MODE, key, ivspec);
byte[] decryptedPaymentData = cipher.doFinal(dataBytes);
// JSON payload
String data = new String(decryptedPaymentData, "UTF-8");
// System.out.println(data);
AppleDecryptData decryptDat = ObjMapper.getInstance().readValue(data, AppleDecryptData.class);
return decryptDat;
} else {
return null;
}
}
private static final byte[] APPLE_OEM = "Apple".getBytes(Charset.forName("US-ASCII"));
private static final byte[] COUNTER = { 0x00, 0x00, 0x00, 0x01 };
private static final byte[] ALG_IDENTIFIER_BYTES = "id-aes256-GCM".getBytes(Charset.forName("US-ASCII"));
/**
* 00000001_16 || sharedSecret || length("AES/GCM/NoPadding") ||
* "AES/GCM/NoPadding" || "Apple" || merchantID
*/
private static byte[] performKDF(byte[] sharedSecret, byte[] merchantId) throws Exception {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(COUNTER);
baos.write(sharedSecret);
baos.write(ALG_IDENTIFIER_BYTES.length);
baos.write(ALG_IDENTIFIER_BYTES);
baos.write(APPLE_OEM);
baos.write(merchantId);
MessageDigest messageDigest = MessageDigest.getInstance("SHA256", PROVIDER_NAME);
return messageDigest.digest(baos.toByteArray());
}
#SuppressWarnings("unused")
private static byte[] performKDF(byte[] sharedSecret, String merchantId) throws Exception {
MessageDigest messageDigest = MessageDigest.getInstance("SHA256", PROVIDER_NAME);
return performKDF(sharedSecret, messageDigest.digest(merchantId.getBytes("UTF-8")));
}
protected static byte[] extractMerchantIdFromCertificateOid() throws Exception {
KeyStore vkeyStore = KeyStore.getInstance("JKS");
vkeyStore.load(GoSecureApplication.class.getResourceAsStream("/kapple_pay.jks"), "".toCharArray());
Enumeration<String> aliases = vkeyStore.aliases();
String alias = null;
while (aliases.hasMoreElements()) {
alias = aliases.nextElement();
}
X509Certificate cert = (X509Certificate) vkeyStore.getCertificate(alias);
byte[] merchantIdentifierTlv = cert.getExtensionValue("1.2.840.113635.100.6.32");
byte[] merchantIdentifier = new byte[64];
System.arraycopy(merchantIdentifierTlv, 4, merchantIdentifier, 0, 64);
return Hex.decode(merchantIdentifier);
}
}

Load RSA public key from file

I've generated a private key with:
openssl genrsa [-out file] –des3
After this I've generated a public key with:
openssl rsa –pubout -in private.key [-out file]
I want to sign some messages with my private key, and verify some other messages with my public key, using code like this:
public String sign(String message) throws SignatureException{
try {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initSign(privateKey);
sign.update(message.getBytes("UTF-8"));
return new String(Base64.encodeBase64(sign.sign()),"UTF-8");
} catch (Exception ex) {
throw new SignatureException(ex);
}
}
public boolean verify(String message, String signature) throws SignatureException{
try {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initVerify(publicKey);
sign.update(message.getBytes("UTF-8"));
return sign.verify(Base64.decodeBase64(signature.getBytes("UTF-8")));
} catch (Exception ex) {
throw new SignatureException(ex);
}
}
I found a solution to convert my private key to PKCS8 format and load it. It works with some code like this:
public PrivateKey getPrivateKey(String filename) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf =
KeyFactory.getInstance("RSA");
return kf.generatePrivate(spec);
}
And finally my question is: How do I load my RSA Public Key from a file?
I think maybe I need to convert my public key file to x509 format, and use X509EncodedKeySpec. But how can I do this?

Below is the relevant information from the link which Zaki provided.
Generate a 2048-bit RSA private key
$ openssl genrsa -out private_key.pem 2048
Convert private Key to PKCS#8 format (so Java can read it)
$ openssl pkcs8 -topk8 -inform PEM -outform DER -in private_key.pem -out private_key.der -nocrypt
Output public key portion in DER format (so Java can read it)
$ openssl rsa -in private_key.pem -pubout -outform DER -out public_key.der
Private key
import java.nio.file.*;
import java.security.*;
import java.security.spec.*;
public class PrivateKeyReader {
public static PrivateKey get(String filename)
throws Exception {
byte[] keyBytes = Files.readAllBytes(Paths.get(filename));
PKCS8EncodedKeySpec spec =
new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePrivate(spec);
}
}
Public key
import java.nio.file.*;
import java.security.*;
import java.security.spec.*;
public class PublicKeyReader {
public static PublicKey get(String filename)
throws Exception {
byte[] keyBytes = Files.readAllBytes(Paths.get(filename));
X509EncodedKeySpec spec =
new X509EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePublic(spec);
}
}

This program is doing almost everything with Public and private keys.
The der format can be obtained but saving raw data ( without encoding base64).
I hope this helps programmers.
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import sun.security.pkcs.PKCS8Key;
import sun.security.pkcs10.PKCS10;
import sun.security.x509.X500Name;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
/**
* #author Desphilboy
* DorOd bar shomA barobach
*
*/
public class csrgenerator {
private static PublicKey publickey= null;
private static PrivateKey privateKey=null;
//private static PKCS8Key privateKey=null;
private static KeyPairGenerator kpg= null;
private static ByteArrayOutputStream bs =null;
private static csrgenerator thisinstance;
private KeyPair keypair;
private static PKCS10 pkcs10;
private String signaturealgorithm= "MD5WithRSA";
public String getSignaturealgorithm() {
return signaturealgorithm;
}
public void setSignaturealgorithm(String signaturealgorithm) {
this.signaturealgorithm = signaturealgorithm;
}
private csrgenerator() {
try {
kpg = KeyPairGenerator.getInstance("RSA");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
System.out.print("No such algorithm RSA in constructor csrgenerator\n");
}
kpg.initialize(2048);
keypair = kpg.generateKeyPair();
publickey = keypair.getPublic();
privateKey = keypair.getPrivate();
}
/** Generates a new key pair
*
* #param int bits
* this is the number of bits in modulus must be 512, 1024, 2048 or so on
*/
public KeyPair generateRSAkys(int bits)
{
kpg.initialize(bits);
keypair = kpg.generateKeyPair();
publickey = keypair.getPublic();
privateKey = keypair.getPrivate();
KeyPair dup= keypair;
return dup;
}
public static csrgenerator getInstance() {
if (thisinstance == null)
thisinstance = new csrgenerator();
return thisinstance;
}
/**
* Returns a CSR as string
* #param cn Common Name
* #param OU Organizational Unit
* #param Org Organization
* #param LocName Location name
* #param Statename State/Territory/Province/Region
* #param Country Country
* #return returns csr as string.
* #throws Exception
*/
public String getCSR(String commonname, String organizationunit, String organization,String localname, String statename, String country ) throws Exception {
byte[] csr = generatePKCS10(commonname, organizationunit, organization, localname, statename, country,signaturealgorithm);
return new String(csr);
}
/** This function generates a new Certificate
* Signing Request.
*
* #param CN
* Common Name, is X.509 speak for the name that distinguishes
* the Certificate best, and ties it to your Organization
* #param OU
* Organizational unit
* #param O
* Organization NAME
* #param L
* Location
* #param S
* State
* #param C
* Country
* #return byte stream of generated request
* #throws Exception
*/
private static byte[] generatePKCS10(String CN, String OU, String O,String L, String S, String C,String sigAlg) throws Exception {
// generate PKCS10 certificate request
pkcs10 = new PKCS10(publickey);
Signature signature = Signature.getInstance(sigAlg);
signature.initSign(privateKey);
// common, orgUnit, org, locality, state, country
//X500Name(String commonName, String organizationUnit,String organizationName,Local,State, String country)
X500Name x500Name = new X500Name(CN, OU, O, L, S, C);
pkcs10.encodeAndSign(x500Name,signature);
bs = new ByteArrayOutputStream();
PrintStream ps = new PrintStream(bs);
pkcs10.print(ps);
byte[] c = bs.toByteArray();
try {
if (ps != null)
ps.close();
if (bs != null)
bs.close();
} catch (Throwable th) {
}
return c;
}
public PublicKey getPublicKey() {
return publickey;
}
/**
* #return
*/
public PrivateKey getPrivateKey() {
return privateKey;
}
/**
* saves private key to a file
* #param filename
*/
public void SavePrivateKey(String filename)
{
PKCS8EncodedKeySpec pemcontents=null;
pemcontents= new PKCS8EncodedKeySpec( privateKey.getEncoded());
PKCS8Key pemprivatekey= new PKCS8Key( );
try {
pemprivatekey.decode(pemcontents.getEncoded());
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
File file=new File(filename);
try {
file.createNewFile();
FileOutputStream fos=new FileOutputStream(file);
fos.write(pemprivatekey.getEncoded());
fos.flush();
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* Saves Certificate Signing Request to a file;
* #param filename is a String containing full path to the file which will be created containing the CSR.
*/
public void SaveCSR(String filename)
{
FileOutputStream fos=null;
PrintStream ps=null;
File file;
try {
file = new File(filename);
file.createNewFile();
fos = new FileOutputStream(file);
ps= new PrintStream(fos);
}catch (IOException e)
{
System.out.print("\n could not open the file "+ filename);
}
try {
try {
pkcs10.print(ps);
} catch (SignatureException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ps.flush();
ps.close();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.print("\n cannot write to the file "+ filename);
e.printStackTrace();
}
}
/**
* Saves both public key and private key to file names specified
* #param fnpub file name of public key
* #param fnpri file name of private key
* #throws IOException
*/
public static void SaveKeyPair(String fnpub,String fnpri) throws IOException {
// Store Public Key.
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
publickey.getEncoded());
FileOutputStream fos = new FileOutputStream(fnpub);
fos.write(x509EncodedKeySpec.getEncoded());
fos.close();
// Store Private Key.
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateKey.getEncoded());
fos = new FileOutputStream(fnpri);
fos.write(pkcs8EncodedKeySpec.getEncoded());
fos.close();
}
/**
* Reads a Private Key from a pem base64 encoded file.
* #param filename name of the file to read.
* #param algorithm Algorithm is usually "RSA"
* #return returns the privatekey which is read from the file;
* #throws Exception
*/
public PrivateKey getPemPrivateKey(String filename, String algorithm) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
String temp = new String(keyBytes);
String privKeyPEM = temp.replace("-----BEGIN PRIVATE KEY-----", "");
privKeyPEM = privKeyPEM.replace("-----END PRIVATE KEY-----", "");
//System.out.println("Private key\n"+privKeyPEM);
BASE64Decoder b64=new BASE64Decoder();
byte[] decoded = b64.decodeBuffer(privKeyPEM);
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePrivate(spec);
}
/**
* Saves the private key to a pem file.
* #param filename name of the file to write the key into
* #param key the Private key to save.
* #return String representation of the pkcs8 object.
* #throws Exception
*/
public String SavePemPrivateKey(String filename) throws Exception {
PrivateKey key=this.privateKey;
File f = new File(filename);
FileOutputStream fos = new FileOutputStream(f);
DataOutputStream dos = new DataOutputStream(fos);
byte[] keyBytes = key.getEncoded();
PKCS8Key pkcs8= new PKCS8Key();
pkcs8.decode(keyBytes);
byte[] b=pkcs8.encode();
BASE64Encoder b64=new BASE64Encoder();
String encoded = b64.encodeBuffer(b);
encoded= "-----BEGIN PRIVATE KEY-----\r\n" + encoded + "-----END PRIVATE KEY-----";
dos.writeBytes(encoded);
dos.flush();
dos.close();
//System.out.println("Private key\n"+privKeyPEM);
return pkcs8.toString();
}
/**
* Saves a public key to a base64 encoded pem file
* #param filename name of the file
* #param key public key to be saved
* #return string representation of the pkcs8 object.
* #throws Exception
*/
public String SavePemPublicKey(String filename) throws Exception {
PublicKey key=this.publickey;
File f = new File(filename);
FileOutputStream fos = new FileOutputStream(f);
DataOutputStream dos = new DataOutputStream(fos);
byte[] keyBytes = key.getEncoded();
BASE64Encoder b64=new BASE64Encoder();
String encoded = b64.encodeBuffer(keyBytes);
encoded= "-----BEGIN PUBLIC KEY-----\r\n" + encoded + "-----END PUBLIC KEY-----";
dos.writeBytes(encoded);
dos.flush();
dos.close();
//System.out.println("Private key\n"+privKeyPEM);
return encoded.toString();
}
/**
* reads a public key from a file
* #param filename name of the file to read
* #param algorithm is usually RSA
* #return the read public key
* #throws Exception
*/
public PublicKey getPemPublicKey(String filename, String algorithm) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
String temp = new String(keyBytes);
String publicKeyPEM = temp.replace("-----BEGIN PUBLIC KEY-----\n", "");
publicKeyPEM = publicKeyPEM.replace("-----END PUBLIC KEY-----", "");
BASE64Decoder b64=new BASE64Decoder();
byte[] decoded = b64.decodeBuffer(publicKeyPEM);
X509EncodedKeySpec spec =
new X509EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePublic(spec);
}
public static void main(String[] args) throws Exception {
csrgenerator gcsr = csrgenerator.getInstance();
gcsr.setSignaturealgorithm("SHA512WithRSA");
System.out.println("Public Key:\n"+gcsr.getPublicKey().toString());
System.out.println("Private Key:\nAlgorithm: "+gcsr.getPrivateKey().getAlgorithm().toString());
System.out.println("Format:"+gcsr.getPrivateKey().getFormat().toString());
System.out.println("To String :"+gcsr.getPrivateKey().toString());
System.out.println("GetEncoded :"+gcsr.getPrivateKey().getEncoded().toString());
BASE64Encoder encoder= new BASE64Encoder();
String s=encoder.encodeBuffer(gcsr.getPrivateKey().getEncoded());
System.out.println("Base64:"+s+"\n");
String csr = gcsr.getCSR( "desphilboy#yahoo.com","baxshi az xodam", "Xodam","PointCook","VIC" ,"AU");
System.out.println("CSR Request Generated!!");
System.out.println(csr);
gcsr.SaveCSR("c:\\testdir\\javacsr.csr");
String p=gcsr.SavePemPrivateKey("c:\\testdir\\java_private.pem");
System.out.print(p);
p=gcsr.SavePemPublicKey("c:\\testdir\\java_public.pem");
privateKey= gcsr.getPemPrivateKey("c:\\testdir\\java_private.pem", "RSA");
BASE64Encoder encoder1= new BASE64Encoder();
String s1=encoder1.encodeBuffer(gcsr.getPrivateKey().getEncoded());
System.out.println("Private Key in Base64:"+s1+"\n");
System.out.print(p);
}
}

Once you have your key stored in a PEM file, you can read it back easily using PemObject and PemReader classes provided by BouncyCastle, as shown in this this tutorial.
Create a PemFile class that encapsulates file handling:
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;
public class PemFile {
private PemObject pemObject;
public PemFile(String filename) throws FileNotFoundException, IOException {
PemReader pemReader = new PemReader(new InputStreamReader(
new FileInputStream(filename)));
try {
this.pemObject = pemReader.readPemObject();
} finally {
pemReader.close();
}
}
public PemObject getPemObject() {
return pemObject;
}
}
Then instantiate private and public keys as usual:
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import org.apache.log4j.Logger;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class Main {
protected final static Logger LOGGER = Logger.getLogger(Main.class);
public final static String RESOURCES_DIR = "src/main/resources/rsa-sample/";
public static void main(String[] args) throws FileNotFoundException,
IOException, NoSuchAlgorithmException, NoSuchProviderException {
Security.addProvider(new BouncyCastleProvider());
LOGGER.info("BouncyCastle provider added.");
KeyFactory factory = KeyFactory.getInstance("RSA", "BC");
try {
PrivateKey priv = generatePrivateKey(factory, RESOURCES_DIR
+ "id_rsa");
LOGGER.info(String.format("Instantiated private key: %s", priv));
PublicKey pub = generatePublicKey(factory, RESOURCES_DIR
+ "id_rsa.pub");
LOGGER.info(String.format("Instantiated public key: %s", pub));
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
}
private static PrivateKey generatePrivateKey(KeyFactory factory,
String filename) throws InvalidKeySpecException,
FileNotFoundException, IOException {
PemFile pemFile = new PemFile(filename);
byte[] content = pemFile.getPemObject().getContent();
PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(content);
return factory.generatePrivate(privKeySpec);
}
private static PublicKey generatePublicKey(KeyFactory factory,
String filename) throws InvalidKeySpecException,
FileNotFoundException, IOException {
PemFile pemFile = new PemFile(filename);
byte[] content = pemFile.getPemObject().getContent();
X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(content);
return factory.generatePublic(pubKeySpec);
}
}
Hope this helps.

#Value("${spring.security.oauth2.resourceserver.jwt.key-value}")
RSAPublicKey key;
key-value can be uri (i.e. "classpath:keys/pub.pcks8.pem") or pem content.
you must include the following deps:
compile project(':spring-security-config')
compile project(':spring-security-oauth2-jose')
compile project(':spring-security-oauth2-resource-server')

Below code works absolutely fine to me and working. This code will read RSA private and public key though java code. You can refer to http://snipplr.com/view/18368/
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
public class Demo {
public static final String PRIVATE_KEY="/home/user/private.der";
public static final String PUBLIC_KEY="/home/user/public.der";
public static void main(String[] args) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
//get the private key
File file = new File(PRIVATE_KEY);
FileInputStream fis = new FileInputStream(file);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) file.length()];
dis.readFully(keyBytes);
dis.close();
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
RSAPrivateKey privKey = (RSAPrivateKey) kf.generatePrivate(spec);
System.out.println("Exponent :" + privKey.getPrivateExponent());
System.out.println("Modulus" + privKey.getModulus());
//get the public key
File file1 = new File(PUBLIC_KEY);
FileInputStream fis1 = new FileInputStream(file1);
DataInputStream dis1 = new DataInputStream(fis1);
byte[] keyBytes1 = new byte[(int) file1.length()];
dis1.readFully(keyBytes1);
dis1.close();
X509EncodedKeySpec spec1 = new X509EncodedKeySpec(keyBytes1);
KeyFactory kf1 = KeyFactory.getInstance("RSA");
RSAPublicKey pubKey = (RSAPublicKey) kf1.generatePublic(spec1);
System.out.println("Exponent :" + pubKey.getPublicExponent());
System.out.println("Modulus" + pubKey.getModulus());
}
}