AES SAMPLE

aes.java

String str = "coucou";

byte[] keyStart = "this is a key".getBytes();
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(keyStart);
kgen.init(256, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();


SecretKeySpec skeySpec = new SecretKeySpec(skey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(str.getBytes(StandardCharsets.UTF_8));

SecretKeySpec skeySpec2 = new SecretKeySpec(skey.getEncoded(), "AES");
Cipher cipher2 = Cipher.getInstance("AES");
cipher2.init(Cipher.DECRYPT_MODE, skeySpec2);
byte[] decrypted = cipher2.doFinal(encrypted);

new String(decrypted, StandardCharsets.UTF_8);