Develop Reference

Encrypt a field to send to another API

I have a request where there is a field "number_token" that I need to encrypt to send to another API to validate. What is the best method to do this?
Example:
"number_token":"123456789"
encrypt:
"number_token":"iIsInN1YieyJpc3MiOiJHZXR3YXk.gcGFnQmFuayBQQI6ImIyYzMxMTlmLWU3ZjktNDZjZS05NTMxLTkyMTNlNWRjNWNiMSIsImlhdCI6MTY1OTgyNjUyOCwiZXhwIjoxNjU5ODI2NzA4fQ.mL-jivitV30N1PLq10CmI4ZWxCcBivGf5QGVus7Vsyw"

There are many factors to be considered but to get started you can use below logic to encrypt. Credits https://www.javaguides.net/2020/02/java-string-encryption-decryption-example.html?m=1
Here is the complete Java program to encrypt and decrypt string or text in Java:
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
public class AESEncryptionDecryption {
private static SecretKeySpec secretKey;
private static byte[] key;
private static final String ALGORITHM = "AES";
public void prepareSecreteKey(String myKey) {
MessageDigest sha = null;
try {
key = myKey.getBytes(StandardCharsets.UTF_8);
sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
secretKey = new SecretKeySpec(key, ALGORITHM);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
public String encrypt(String strToEncrypt, String secret) {
try {
prepareSecreteKey(secret);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, secretKey);
return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8")));
} catch (Exception e) {
System.out.println("Error while encrypting: " + e.toString());
}
return null;
}
public String decrypt(String strToDecrypt, String secret) {
try {
prepareSecreteKey(secret);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, secretKey);
return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
} catch (Exception e) {
System.out.println("Error while decrypting: " + e.toString());
}
return null;
}
public static void main(String[] args) {
final String secretKey = "secrete";
String originalString = "javaguides";
AESEncryptionDecryption aesEncryptionDecryption = new AESEncryptionDecryption();
String encryptedString = aesEncryptionDecryption.encrypt(originalString, secretKey);
String decryptedString = aesEncryptionDecryption.decrypt(encryptedString, secretKey);
System.out.println(originalString);
System.out.println(encryptedString);
System.out.println(decryptedString);
}
}

Why does my AES decryption return extra bytes?

Regardless of the file size, 32 bytes of additional characters are appended to each decrypted file. I could just cut off the 32 bytes, but where did they come from and how can I avoid them in the output file?
This is my source code:
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.SecureRandom;
import java.security.spec.KeySpec;
public class EtAesCrypto {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
private static final int KEY_LENGTH = 256;
private static final int SALT_LENGTH = 16;
private static final int IV_LENGTH = 12;
private static final int AUT_TAG_LENGTH = 128;
private static final int ITERATIONS = 100;
private static final String ALGORITHM = "AES";
private static final String SECRET_KEY_ALGORITHM = "PBKDF2WithHmacSHA256";
private static final String TRANSFORMATION = "AES/GCM/NoPadding";
private String msg;
public void encrypt(String path2Original, String path2Encrypted, String password) {
try (FileOutputStream out = new FileOutputStream(path2Encrypted)) {
byte[] salt = new byte[SALT_LENGTH];
byte[] iv = new byte[IV_LENGTH];
SecureRandom secureRandom = new SecureRandom();
secureRandom.nextBytes(salt);
SecretKeyFactory factory = SecretKeyFactory.getInstance(SECRET_KEY_ALGORITHM);
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, ITERATIONS, KEY_LENGTH);
SecretKey tmp = factory.generateSecret(spec);
SecretKeySpec skey = new SecretKeySpec(tmp.getEncoded(), ALGORITHM);
secureRandom.nextBytes(iv);
logger.trace("IV length: {}", iv.length);
out.write(salt);
out.write(iv);
Cipher ci = Cipher.getInstance(TRANSFORMATION);
GCMParameterSpec parameterSpec = new GCMParameterSpec(AUT_TAG_LENGTH, iv);
ci.init(Cipher.ENCRYPT_MODE, skey, parameterSpec);
try (FileInputStream in = new FileInputStream(path2Original)) {
processStream(ci, in, out);
}
} catch (Exception e) {
throw new RuntimeException("Encryption of file with id failed.");
}
}
public void decrypt(String path2Encrypted, OutputStream os, String password, String fileId) {
try (FileInputStream in = new FileInputStream(path2Encrypted)) {
doDecryption(in, os, password);
} catch (Exception e){
msg = String.format("Decryption of file with id '%s' failed.", fileId);
logger.warn("Decryption of file '{}' with id '{}' failed: {}", path2Encrypted, fileId, e.getMessage(), e);
throw new RuntimeException(msg);
}
}
public void decrypt(String path2Encrypted, String path2Decrypted, String password, String fileId) {
try (FileInputStream in = new FileInputStream(path2Encrypted)) {
try (FileOutputStream os = new FileOutputStream(path2Decrypted)) {
doDecryption(in, os, password);
}
} catch (Exception e){
msg = String.format("Decryption of file with id '%s' failed.", fileId);
logger.warn("Decryption of file '{}' with id '{}' failed: {}", path2Encrypted, fileId, e.getMessage(), e);
throw new RuntimeException(msg);
}
}
private void doDecryption(InputStream in, OutputStream out, String password) throws Exception {
byte[] salt = new byte[SALT_LENGTH];
byte[] iv = new byte[IV_LENGTH];
int saltBytes = in.read(salt);
int ivBytes = in.read(iv);
SecretKeyFactory factory = SecretKeyFactory.getInstance(SECRET_KEY_ALGORITHM);
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, ITERATIONS, KEY_LENGTH);
SecretKey tmp = factory.generateSecret(spec);
SecretKeySpec skey = new SecretKeySpec(tmp.getEncoded(), ALGORITHM);
Cipher ci = Cipher.getInstance(TRANSFORMATION);
GCMParameterSpec parameterSpec = new GCMParameterSpec(AUT_TAG_LENGTH, iv);
ci.init(Cipher.ENCRYPT_MODE, skey, parameterSpec);
processStream(ci, in, out);
}
private void processStream(Cipher ci, InputStream in, OutputStream out) throws Exception {
byte[] inBuffer = new byte[1024];
int len;
while ((len = in.read(inBuffer)) != -1) {
byte[] outBuffer = ci.update(inBuffer, 0, len);
if (outBuffer != null)
out.write(outBuffer);
}
byte[] outBuffer = ci.doFinal();
if (outBuffer != null)
out.write(outBuffer);
}
}

You should use Cipher.DECRYPT_MODE when decrypting.
The additional bytes are the GCM tag (MAC). It is created during encryption and checked during decryption.
In GCM mode the process of encryption and decryption is identical (XOR), that's why decrypting with Cipher.ENCRYPT_MODE appears to work, except for the MAC part.

blowfish key file illegal key size exception in linux tomcat deployment

I have a web app which is deployed on tomcat in both Linux and windows environment . Blowfish algo has been implemented for login password encryption/security check. It works fine in windows but throws illegal key size exception in linux. key file is packed with war
I have gone through multiple post but nothing really helped me.
generating key file
/** Generate a secret TripleDES encryption/decryption key */
KeyGenerator keygen = KeyGenerator.getInstance(SecurityConstant.BLOW_FISH_ALGO);
// Use it to generate a key
SecretKey key = keygen.generateKey();
// Convert the secret key to an array of bytes like this
byte[] rawKey = key.getEncoded();
// Write the raw key to the file
String keyPath = getBlowFishKeyPath();
FileOutputStream out = new FileOutputStream(keyPath);
Writer writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
Files.write( Paths.get(keyPath),rawkey,StandardOpenOption.CREATE);
writer.close();
key comparision
String hexCipher = null;
try {
byte[] byteClearText = pwd.getBytes("UTF-8");
byte[] ivBytes = SecurityUtil.hexToBytes("0000000000000000");
// read secretkey from key file
byte[] secretKeyByte = secretKey.getBytes();
Cipher cipher = null;
SecretKeySpec key = new SecretKeySpec(secretKeyByte, SecurityConstant.BLOW_FISH_ALGO);
// Create and initialize the encryption engine
cipher = Cipher.getInstance(SecurityConstant.BLOW_FISH_CBC_ZEROBYTE_ALGO, SecurityConstant.BC);
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // throws exception
byte[] cipherText = new byte[cipher.getOutputSize(byteClearText.length)];
int ctLength = cipher.update(byteClearText, 0, byteClearText.length, cipherText, 0);
ctLength += cipher.doFinal(cipherText, ctLength);
hexCipher = SecurityUtil.bytesToHex(cipherText);// hexdecimal password stored in DB
} catch (Exception e) {
ExceptionLogger.logException(logger, e);
}
made it simpler to test
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.io.FileUtils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class SecTest {
public static void main(String[] args) throws NoSuchAlgorithmException {
/** Generate a secret TripleDES encryption/decryption key */
Security.addProvider(new BouncyCastleProvider());
KeyGenerator keygen = KeyGenerator.getInstance("Blowfish");
// Use it to generate a key
SecretKey key = keygen.generateKey();
// Convert the secret key to an array of bytes like this
byte[] rawKey = key.getEncoded();
// Write the raw key to the file
String keyPath = "/data2/key/BlowFish.key";
FileOutputStream out = null;
try {
out = new FileOutputStream(keyPath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Writer writer = null;
try {
writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
Files.write( Paths.get(keyPath),rawKey,StandardOpenOption.CREATE);
writer.close();
out.close();
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
generateHexCode("a");
}
private static void generateHexCode(String pwd) {
String hexCipher = null;
try {
byte[] byteClearText = pwd.getBytes("UTF-8");
byte[] ivBytes = hexToBytes("0000000000000000");
// read secretkey from key file
byte[] secretKeyByte = readSecretKey().getBytes();
Cipher cipher = null;
SecretKeySpec key = new SecretKeySpec(secretKeyByte, "Blowfish");
// Create and initialize the encryption engine
cipher = Cipher.getInstance("Blowfish/CBC/ZeroBytePadding", "BC");
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // throws exception
byte[] cipherText = new byte[cipher.getOutputSize(byteClearText.length)];
int ctLength = cipher.update(byteClearText, 0, byteClearText.length, cipherText, 0);
ctLength += cipher.doFinal(cipherText, ctLength);
hexCipher = bytesToHex(cipherText);// hexdecimal password stored in DB
System.out.println("hex cipher is "+hexCipher);
} catch (Exception e) {
e.printStackTrace();
}
}
private static String readSecretKey() {
byte[] rawkey = null;
String file ="";
// Read the raw bytes from the keyfile
String keyFile = "/data2/key/BlowFish.key";
String is = null;
try {
is = FileUtils.readFileToString(new File(keyFile),"UTF-8");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return is;
}
public static byte[] hexToBytes(String str) {
byte[] bytes = null;
if (str != null && str.length() >= 2) {
int len = str.length() / 2;
byte[] buffer = new byte[len];
for (int i = 0; i < len; i++) {
buffer[i] = (byte) Integer.parseInt(str.substring(i * 2, i * 2 + 2), 16);
}
bytes = buffer;
}
return bytes;
}
public static String bytesToHex(byte[] data) {
if (data == null) {
return null;
} else {
int len = data.length;
StringBuilder str = new StringBuilder();
for (int i = 0; i < len; i++) {
if ((data[i] & 0xFF) < 16) {
str = str.append("0").append(java.lang.Integer.toHexString(data[i] & 0xFF));
} else {
str.append(java.lang.Integer.toHexString(data[i] & 0xFF));
}
}
return str.toString().toUpperCase();
}
}
}
Made a simple program to test it out . This also runs fine on windows but fails on linux. any clue ?

InvalidKeyException DER input not a bit string

import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;
import javax.crypto.Cipher;
import org.apache.commons.codec.binary.Base64;
public class DJExampleDecryptCode
{
public static void main(String[] args)
{
try
{
String encryptedText = "q3sEN1NZZyseoFy9H3WIwNf9jpGrDTTqh/AticRV2pnb1KZ5lieuK5jw3JgctgYUnTE03xnMcOL50UGKZ4dbYEt5XGCZyNVgh1qVGF7Vgnvi5PKndnpKLcoSUJCcbu/lyLI2P+Zd7ZH0/tRKRn1zqrPAWUH3VjtUt7qkIcdIYyaoHP5I7eiZRk6FL9ugUQJnz8WFgM4mcRJ5Zs/NLdaXKeHMO4nPQBTOLNaPdNxW2MM+qlv0HN/fs4rPMRGUw0xXhjWsmSNqadASfn7UX4fL79CmGyKfm8ol4njZakZbsfes/zstc5Su0swycfFSkjXAjPjvMGdBs5/HSLXYAvQPoA==";
String TextToEncrypt = "Test";
String decryptedString = decrypt(encryptedText);
String encryptedString = encrypt(TextToEncrypt);
//Printing
System.out.println("Decrypted Text: " + decryptedString);
System.out.println("Encrypted Text: " + encryptedString);
}
catch (Exception e)
{
e.printStackTrace();
}
}
//public static String decrypt(String text, String privateKeyString) throws GeneralSecurityException
public static String decrypt(String text) throws GeneralSecurityException
{
String DJPrivateKey = ".....";
PrivateKey privateKey = stringToPrivateKey(DJPrivateKey);
byte[] dectyptedText = null;
try
{
final Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
dectyptedText = cipher.doFinal(base64Decode(text));
}
catch (Exception ex)
{
ex.printStackTrace();
}
return new String(dectyptedText);
}
public static String encrypt(String data) throws GeneralSecurityException
{
String PCMSPublicKey = "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";
PublicKey publicKey = stringToPublicKey(PCMSPublicKey);
byte[] enctyptedText = null;
try
{
final Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
enctyptedText = cipher.doFinal(base64Decode(data));
}
catch (Exception ex)
{
ex.printStackTrace();
}
return new String(enctyptedText);
}
public static byte[] base64Decode(String encodedString)
{
Base64 myBase64 = new Base64();
return myBase64.decode(encodedString);
}
public static PrivateKey stringToPrivateKey(String privateKeyString) throws GeneralSecurityException
{
byte[] clear = base64Decode(privateKeyString);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(clear);
KeyFactory fact = KeyFactory.getInstance("RSA");
PrivateKey priv = fact.generatePrivate(keySpec);
Arrays.fill(clear, (byte) 0);
return priv;
}
public static PublicKey stringToPublicKey(String publicKeyString) throws GeneralSecurityException
{
byte[] clear = base64Decode(publicKeyString);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(clear);
KeyFactory fact = KeyFactory.getInstance("RSA");
PublicKey pub = fact.generatePublic(keySpec);
Arrays.fill(clear, (byte) 0);
return pub;
}
}
I have the above java code that does encryption and decryption. The decryption works fine, which uses the private key, but when I ran the encryption part using the public key I hard-coded, I got the below errors,
java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException: DER input not a bit string
at sun.security.rsa.RSAKeyFactory.engineGeneratePublic(RSAKeyFactory.java:205)
at java.security.KeyFactory.generatePublic(KeyFactory.java:334)
at DJExampleDecryptCode.stringToPublicKey(DJExampleDecryptCode.java:109)
at DJExampleDecryptCode.encrypt(DJExampleDecryptCode.java:64)
at DJExampleDecryptCode.main(DJExampleDecryptCode.java:26)
Caused by: java.security.InvalidKeyException: IOException: DER input not a bit string
at sun.security.x509.X509Key.decode(X509Key.java:397)
at sun.security.x509.X509Key.decode(X509Key.java:403)
at sun.security.rsa.RSAPublicKeyImpl.<init>(RSAPublicKeyImpl.java:83)
can anyone give me some suggestions? thanks a lot

How do you generate, sign and read digital signatures in java?

I am becoming intermediate java programmer. I have tried hard to find out how to sign and read digital signatures in java for a net program i have been working on. I have been able to generate private and public keys with the tutorial at http://docs.oracle.com/javase/tutorial/security/apisign/index.html but have not been able to do anything with them. Although I know how to generate keys i didn't put it in because i wasn't sure if i had done them correctly.
Here is a simplified version of my code:
Main class:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws IOException {
Main main = new Main();
Scanner s = new Scanner(System.in);
while (true) {
//This is where i added a command detector so that the program can be in one class
System.out.println("Choose a command from the following:\nGenerate keys\nSign message\nRead message");
String command = s.nextLine();
if (command.equalsIgnoreCase("Generate key")
|| command.equalsIgnoreCase("Generate")) {
/* The code for generating the keys is here */
File f = new File("C:\\Users\\spencer\\Documents\\Stack ex\\src\\app","public.key");
File fi = new File("C:\\Users\\spencer\\Documents\\Stack ex\\src\\app","private.key");
if(!f.isFile()||!fi.isFile()) {
Make make =new Make();
Make.main(args);
}
else{
try {
String path = "C:\\Users\\spencer\\Documents\\ds test 3\\src\\app";
KeyPair loadedKeyPair = main.LoadKeyPair(path, "DSA");
System.out.println("Key pair already exists!");
System.out.println("Loaded Key Pair:");
main.dumpKeyPair(loadedKeyPair);
} catch (Exception e) {
e.printStackTrace();
return;
}
}
}
if (command.equalsIgnoreCase("Sign message")
|| command.equalsIgnoreCase("Sign")) {
long signature = 0;
System.out.println("What is your private key");
String pkey = s.nextLine();
long prkey = Long.parseLong(pkey);
System.out.println("What is you message");
String message = s.nextLine();
/* The code for signing the message goes here */
System.out.println("Signature:"+signature);
} else if (command.equalsIgnoreCase("Read message")
|| command.equalsIgnoreCase("Read")) {
String message = null;
System.out.println("What is the signature");
String sign = s.nextLine();
long signature = Long.parseLong(sign);
/* The code for reading the message goes here */
System.out.println(message);
}
}
}
private void dumpKeyPair(KeyPair keyPair) {
PublicKey pub = keyPair.getPublic();
System.out.println("Public Key: " + getHexString(pub.getEncoded()));
PrivateKey priv = keyPair.getPrivate();
System.out.println("Private Key: " + getHexString(priv.getEncoded()));
}
private String getHexString(byte[] b) {
String result = "";
for (int i = 0; i < b.length; i++) {
result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
}
return result;
}
public KeyPair LoadKeyPair(String path, String algorithm)
throws IOException, NoSuchAlgorithmException,
InvalidKeySpecException {
// Read Public Key.
File filePublicKey = new File(path + "/public.key");
FileInputStream fis = new FileInputStream(path + "/public.key");
byte[] encodedPublicKey = new byte[(int) filePublicKey.length()];
fis.read(encodedPublicKey);
fis.close();
// Read Private Key.
File filePrivateKey = new File(path + "/private.key");
fis = new FileInputStream(path + "/private.key");
byte[] encodedPrivateKey = new byte[(int) filePrivateKey.length()];
fis.read(encodedPrivateKey);
fis.close();
// Generate KeyPair.
KeyFactory keyFactory = KeyFactory.getInstance(algorithm);
X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(
encodedPublicKey);
PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);
PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(
encodedPrivateKey);
PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);
return new KeyPair(publicKey, privateKey);
}
}
Make class:
import java.io.*;
import java.security.*;
import java.security.spec.*;
public class Make {
public static void main(String args[]) {
Make adam = new Make();
try {
String path = "C:\\Users\\spencer\\Documents\\Stack ex\\src\\app";
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
keyGen.initialize(512);
KeyPair generatedKeyPair = keyGen.genKeyPair();
System.out.println("Generated Key Pair");
adam.dumpKeyPair(generatedKeyPair);
adam.SaveKeyPair(path, generatedKeyPair);
} catch (Exception e) {
e.printStackTrace();
return;
}
}
private void dumpKeyPair(KeyPair keyPair) {
PublicKey pub = keyPair.getPublic();
System.out.println("Public Key: " + getHexString(pub.getEncoded()));
PrivateKey priv = keyPair.getPrivate();
System.out.println("Private Key: " + getHexString(priv.getEncoded()));
}
private String getHexString(byte[] b) {
String result = "";
for (int i = 0; i < b.length; i++) {
result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
}
return result;
}
public void SaveKeyPair(String path, KeyPair keyPair) throws IOException {
PrivateKey privateKey = keyPair.getPrivate();
PublicKey publicKey = keyPair.getPublic();
// Store Public Key.
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
publicKey.getEncoded());
FileOutputStream fos = new FileOutputStream(path + "/public.key");
fos.write(x509EncodedKeySpec.getEncoded());
fos.close();
// Store Private Key.
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(
privateKey.getEncoded());
fos = new FileOutputStream(path + "/private.key");
fos.write(pkcs8EncodedKeySpec.getEncoded());
fos.close();
}
}
I need a little help with signing and reading the signature.