Symmetric Encryption

Cryptography is a stateful wrapper around javax.crypto.Cipher. Create a new instance for each independent operation; do not share one instance between threads.

Generic Cipher API

Provide the transformation, cipher mode, key material, and source data, then obtain bytes, text, Base64, or hexadecimal output.

import com.ajaxjs.util.cryptography.Cryptography;
import javax.crypto.Cipher;

Cryptography cipher = new Cryptography("AES", Cipher.ENCRYPT_MODE);
cipher.setKeyData(keyBytes);
cipher.setDataStr("hello");
String encrypted = cipher.doCipherAsBase64Str();

For decryption, construct the helper with Cipher.DECRYPT_MODE, supply the same key, and load the ciphertext using setDataStrBase64().

The class also provides convenience methods for AES, DES, and 3DES. Use DES and 3DES only when communicating with an existing legacy system.

Password-based encryption

PBE_encode() and PBE_decode() derive an AES-GCM key using PBKDF2 with HMAC-SHA256. Use a unique random salt per encrypted value and store it alongside the ciphertext.

byte[] salt = Cryptography.initSalt();
byte[] encrypted = Cryptography.PBE_encode("secret", password, salt, 100_000);
String plain = Cryptography.PBE_decode(encrypted, password, salt, 100_000);

The iteration count must be at least 100_000. AES-GCM authenticates the ciphertext: decryption fails if it is altered or the password, salt, or nonce does not match.