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package security;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.Mac;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
public class Sample {
public static void main(String[] args) throws Exception {
String password = "12341234@xxxx!'9876";
String msg = "This is the message";
System.out.println("Encrypt '" + msg + "'");
byte[] encrypted = encrypt(msg, password);
System.out.println(bytesToHex(encrypted));
String msg2 = decrypt(encrypted, password);
System.out.println("Descrypt '" + msg2 + "'");
}
public static byte[] encrypt(String message, String password) throws Exception {
SecureRandom rand = new SecureRandom();
byte[] messageBytes = message.getBytes(StandardCharsets.UTF_8);
try (ByteArrayOutputStream out = new ByteArrayOutputStream();
InputStream in = new ByteArrayInputStream(messageBytes)) {
byte[] salt = new byte[8];
rand.nextBytes(salt);
out.write(salt);
byte[] derivatedSalt = new byte[8];
rand.nextBytes(derivatedSalt);
out.write(derivatedSalt);
byte[] iv = new byte[16];
rand.nextBytes(iv);
out.write(iv);
ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
long length = messageBytes.length;
buffer.putLong(length);
byte[] lengthBytes = buffer.array();
out.write(lengthBytes);
byte[] aesKey = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
.generateSecret(new PBEKeySpec(password.toCharArray(), salt, 60000, 256)).getEncoded();
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(aesKey, "AES"), new IvParameterSpec(iv));
Mac hmac = Mac.getInstance("HmacSHA256");
byte[] key1 = saltedSHA256(saltedSHA256(aesKey, derivatedSalt), derivatedSalt);
hmac.init(new SecretKeySpec(key1, "HmacSHA256"));
hmac.update(iv);
hmac.update(salt);
byte[] ibuf = new byte[8192];
int len;
while ((len = in.read(ibuf)) != -1) {
byte[] obuf = ci.update(ibuf, 0, len);
if (obuf != null) {
out.write(obuf);
hmac.update(ibuf, 0, len);
}
}
byte[] obuf = ci.doFinal();
if (obuf != null) {
out.write(obuf);
}
byte[] bmac = hmac.doFinal();
out.write(bmac);
return out.toByteArray();
}
}
public static String decrypt(byte[] xx, String password) throws Exception {
try (InputStream in = new ByteArrayInputStream(xx);
ByteArrayOutputStream out = new ByteArrayOutputStream()) {
byte[] salt = new byte[8];
read(in, salt);
byte[] derivatedSalt = new byte[8];
read(in, derivatedSalt);
byte[] iv = new byte[16];
read(in, iv);
byte[] lentghBytes = new byte[Long.BYTES];
read(in, lentghBytes);
ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
buffer.put(lentghBytes);
buffer.flip();// need flip
long length = buffer.getLong();
byte[] aesKey = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
.generateSecret(new PBEKeySpec(password.toCharArray(), salt, 60000, 256)).getEncoded();
Cipher ci = Cipher.getInstance("AES/CBC/PKCS5Padding");
ci.init(Cipher.DECRYPT_MODE, new SecretKeySpec(aesKey, "AES"), new IvParameterSpec(iv));
byte[] key1 = saltedSHA256(saltedSHA256(aesKey, derivatedSalt), derivatedSalt);
Mac hmac = Mac.getInstance("HmacSHA256");
hmac.init(new SecretKeySpec(key1, "HmacSHA256"));
hmac.update(iv);
hmac.update(salt);
long tailleToread = (length / 16 + 1) * 16;
long resteALire = tailleToread;
int bufsize = 8192;
while (resteALire > 0) {
int blockToRead = Math.min((resteALire < bufsize ? (int) resteALire : bufsize + 500), bufsize);
byte[] ibuf = in.readNBytes(blockToRead);
int len = ibuf.length;
resteALire -= len;
byte[] obuf = ci.update(ibuf, 0, len);
if (obuf != null) {
out.write(obuf);
hmac.update(obuf);
}
}
byte[] obuf = ci.doFinal();
if (obuf != null) {
out.write(obuf);
hmac.update(obuf);
}
byte[] bmac = hmac.doFinal();
byte[] readsha = in.readAllBytes();
if (!Arrays.equals(bmac, readsha)) {
throw new Exception("HMAC error");
}
return out.toString(StandardCharsets.UTF_8);
}
}
private static void read(InputStream inputStream, byte[] buffer) throws IOException {
int bufferLength = buffer.length;
int totalBytesRead = 0;
int bytesRead;
while ((bytesRead = inputStream.read(buffer, totalBytesRead, bufferLength - totalBytesRead)) != -1) {
totalBytesRead += bytesRead;
if (totalBytesRead == bufferLength) {
break;
}
}
}
private static byte[] saltedSHA256(byte[] data, byte[] salt) throws NoSuchAlgorithmException {
byte[] bytes = new byte[data.length + salt.length];
System.arraycopy(data, 0, bytes, 0, data.length);
System.arraycopy(salt, 0, bytes, data.length, salt.length);
MessageDigest digest = MessageDigest.getInstance("SHA-256");
return digest.digest(bytes);
}
public static String bytesToHex(byte[] bytes) {
StringBuilder hexStringBuilder = new StringBuilder(2 * bytes.length);
for (byte b : bytes) {
hexStringBuilder.append(String.format("%02x", b));
}
return hexStringBuilder.toString();
}
} |
