public class AESUtil{
private static final String CipherMode = "AES/ECB/PKCS5Padding";
private static SecretKeySpec createKey(String password) throws Exception {
byte[] data;
StringBuffer sb = new StringBuffer(32);
sb.append(password);
while (sb.length() < 32) {
sb.append("0");
}
if (sb.length() > 32) {
sb.setLength(32);
}
data = sb.toString().getBytes("UTF-8");
return new SecretKeySpec(data, "AES");
}
public static byte[] encrypt(byte[] content, String password) throws Exception {
SecretKeySpec key = createKey(password);
System.out.println(key);
Cipher cipher = Cipher.getInstance(CipherMode);
cipher.init(Cipher.ENCRYPT_MODE, key);
return cipher.doFinal(content);
}
public static String encrypt(String content, String password) throws Exception {
byte[] data = content.getBytes("UTF-8");
data = encrypt(data, password);
return byte2hex(data);
}
public static byte[] decrypt(byte[] content, String password) throws Exception {
SecretKeySpec key = createKey(password);
Cipher cipher = Cipher.getInstance(CipherMode);
cipher.init(Cipher.DECRYPT_MODE, key);
return cipher.doFinal(content);
}
public static String decrypt(String content, String password) throws Exception {
byte[] data = hex2byte(content);
data = decrypt(data, password);
if (data == null) return null;
return new String(data, "UTF-8");
}
/*字节数组转成16进制字符串 */
public static String byte2hex(byte[] b) { // 一个字节的数，
StringBuilder sb = new StringBuilder(b.length * 2);
String tmp;
for (byte aB : b) {
tmp = (Integer.toHexString(aB & 0XFF));
if (tmp.length() == 1) {
sb.append("0");
}
sb.append(tmp);
}
return sb.toString().toUpperCase();
}
private static byte[] hex2byte(String inputString) {
if (inputString == null || inputString.length() < 2) {
return new byte[0];
}
inputString = inputString.toLowerCase();
int l = inputString.length() / 2;
byte[] result = new byte[l];
for (int i = 0; i < l; ++i) {
String tmp = inputString.substring(2 * i, 2 * i + 2);
result[i] = (byte) (Integer.parseInt(tmp, 16) & 0xFF);
}
return result;
}
}
public static String encrypt(String input, String key){
byte[] crypted = null;
try{
SecretKeySpec skey = new SecretKeySpec(key.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, skey);
crypted = cipher.doFinal(input.getBytes());
}catch(Exception e){
System.out.println(e.toString());
}
return new String(Base64.encode(crypted, Base64.NO_WRAP));
}
public static String decrypt(String input, String key){
byte[] output = null;
try{
SecretKeySpec skey = new SecretKeySpec(key.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, skey);
output = cipher.doFinal(Base64.decode(input, Base64.NO_WRAP));
}catch(Exception e){
System.out.println(e.toString());
}
return new String(output);
}
//AESCrypt-ObjC uses CBC and PKCS7Padding
private static final String AES_MODE = "AES/CBC/PKCS7Padding";
private static final String CHARSET = "UTF-8";
//AESCrypt-ObjC uses SHA-256 (and so a 256-bit key)
private static final String HASH_ALGORITHM = "SHA-256";
//AESCrypt-ObjC uses blank IV (not the best security, but the aim here is compatibility)
private static final byte[] ivBytes = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
/**
* Generates SHA256 hash of the password which is used as key
*
* @param password used to generated key
* @return SHA256 of the password
*/
private static SecretKeySpec generateKey(final String password) throws NoSuchAlgorithmException, UnsupportedEncodingException {
final MessageDigest digest = MessageDigest.getInstance(HASH_ALGORITHM);
byte[] bytes = password.getBytes("UTF-8");
digest.update(bytes, 0, bytes.length);
byte[] key = digest.digest();
return new SecretKeySpec(key, "AES");
}
/**
* Encrypt and encode message using 256-bit AES with key generated from password.
*
*
* @param password used to generated key
* @param message the thing you want to encrypt assumed String UTF-8
* @return Base64 encoded CipherText
* @throws GeneralSecurityException if problems occur during encryption
*/
public static String encrypt(final String password, String message)
throws GeneralSecurityException {
try {
final SecretKeySpec key = generateKey(password);
byte[] cipherText = encrypt(key, ivBytes, message.getBytes(CHARSET));
return Base64.encodeToString(cipherText, Base64.NO_WRAP);
} catch (UnsupportedEncodingException e) {
throw new GeneralSecurityException(e);
}
}
/**
* More flexible AES encrypt that doesn't encode
* @param key AES key typically 128, 192 or 256 bit
* @param iv Initiation Vector
* @param message in bytes (assumed it's already been decoded)
* @return Encrypted cipher text (not encoded)
* @throws GeneralSecurityException if something goes wrong during encryption
*/
public static byte[] encrypt(final SecretKeySpec key, final byte[] iv, final byte[] message)
throws GeneralSecurityException {
final Cipher cipher = Cipher.getInstance(AES_MODE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);
return cipher.doFinal(message);
}
/**
* Decrypt and decode ciphertext using 256-bit AES with key generated from password
*
* @param password used to generated key
* @param base64EncodedCipherText the encrpyted message encoded with base64
* @return message in Plain text (String UTF-8)
* @throws GeneralSecurityException if there's an issue decrypting
*/
public static String decrypt(final String password, String base64EncodedCipherText)
throws GeneralSecurityException {
try {
final SecretKeySpec key = generateKey(password);
byte[] decodedCipherText = Base64.decode(base64EncodedCipherText, Base64.NO_WRAP);
byte[] decryptedBytes = decrypt(key, ivBytes, decodedCipherText);
return new String(decryptedBytes, CHARSET);
} catch (UnsupportedEncodingException e) {
throw new GeneralSecurityException(e);
}
}
/**
* More flexible AES decrypt that doesn't encode
*
* @param key AES key typically 128, 192 or 256 bit
* @param iv Initiation Vector
* @param decodedCipherText in bytes (assumed it's already been decoded)
* @return Decrypted message cipher text (not encoded)
* @throws GeneralSecurityException if something goes wrong during encryption
*/
public static byte[] decrypt(final SecretKeySpec key, final byte[] iv, final byte[] decodedCipherText)
throws GeneralSecurityException {
final Cipher cipher = Cipher.getInstance(AES_MODE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
return cipher.doFinal(decodedCipherText);
}
/**
* Converts byte array to hexidecimal useful for logging and fault finding
* @param bytes
* @return
*/
private static String bytesToHex(byte[] bytes) {
final char[] hexArray = {'0', '1', '2', '3', '4', '5', '6', '7', '8',
'9', 'A', 'B', 'C', 'D', 'E', 'F'};
char[] hexChars = new char[bytes.length * 2];
int v;
for (int j = 0; j < bytes.length; j++) {
v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
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