public class Aes256 {
public static void main(String[] args) throws Exception{
String str = "김나리";
Aes256 app = new Aes256();
str = app.encrypt(str);
System.out.println("str: "+str);
str = app.decrypt(str);
System.out.println("str: "+str);
}
private static final int keySize = 256;
private static final int iterationCount = 10000;//암호화 키 생성 횟수
private static String salt = "3FF2EC019C627B945225DEBAD71A01B6985FE84C95A70EB132882F88C0A59A55";//AES256 기준 64자리 16진수
private static String iv = "F27D5C9927726BCEFE7510B1BDD3D137";//AES256 기준 32자리 16진수
private static final String passPhrase = "KNUHAPI";
private final Cipher cipher;
public Aes256() throws Exception {
try {
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public String encrypt(String plaintext) throws Exception {
return encrypt(salt, iv, passPhrase, plaintext);
}
public String decrypt(String ciphertext) throws Exception {
return decrypt(salt, iv, passPhrase, ciphertext);
}
private String encrypt(String salt, String iv, String passPhrase, String plaintext) throws Exception {
SecretKey key = generateKey(salt, passPhrase);
byte[] encrypted = doFinal(Cipher.ENCRYPT_MODE, key, iv, plaintext.getBytes("UTF-8"));
return encodeBase64(encrypted);
}
private String decrypt(String salt, String iv, String passPhrase, String ciphertext) throws Exception {
SecretKey key = generateKey(salt, passPhrase);
byte[] decrypted = doFinal(Cipher.DECRYPT_MODE, key, iv, decodeBase64(ciphertext));
return new String(decrypted, "UTF-8");
}
private byte[] doFinal(int encryptMode, SecretKey key, String iv, byte[] bytes) throws Exception {
cipher.init(encryptMode, key, new IvParameterSpec(decodeHex(iv)));
return cipher.doFinal(bytes);
}
private SecretKey generateKey(String salt, String passPhrase) throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(passPhrase.toCharArray(), decodeHex(salt), iterationCount, keySize);
SecretKey key = new SecretKeySpec(factory.generateSecret(spec).getEncoded(), "AES");
return key;
}
private static String encodeBase64(byte[] bytes) {
byte[] encodeByte = Base64.encodeBase64(bytes);
return Base64.encodeBase64String(encodeByte);
}
private static byte[] decodeBase64(String str) {
byte[] decodeByte = Base64.decodeBase64(str);
return Base64.decodeBase64(decodeByte);
}
private static String encodeHex(byte[] bytes) {
return Hex.encodeHexString(bytes);
}
private static byte[] decodeHex(String str) throws Exception {
return Hex.decodeHex(str.toCharArray());
}
}
