Bonjour, voici du code permettant de chiffrer et déchiffrer un String en Java
Votre avis m'intéresse au sujet de la sécurité d'une telle utilisation ?

Merci

Code : Sélectionner tout - Visualiser dans une fenêtre à part
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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();
	}
}