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October 12, 2015 15:32
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simple AES Crypt in java
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package com.classicharmony.testme2; | |
import android.util.Base64; | |
import android.util.Log; | |
import java.io.UnsupportedEncodingException; | |
import java.security.GeneralSecurityException; | |
import java.security.MessageDigest; | |
import java.security.NoSuchAlgorithmException; | |
import javax.crypto.Cipher; | |
import javax.crypto.spec.IvParameterSpec; | |
import javax.crypto.spec.SecretKeySpec; | |
//-------- encryption decryption AES ----------- | |
// | |
// byte[] ivBytes = {0x00, 0x12, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x23, 0x52, 0x00, 0x00, 0x00, 0x00}; | |
// | |
// SecretKeySpec secretKeySpec = new SecretKeySpec(ivBytes, "AES"); | |
// //---------------------- | |
// | |
// | |
// String message = "hello world!"; | |
// byte[] byte_message = message.getBytes(Charset.forName("UTF-8")); | |
// byte[] output = new byte[]{}; | |
// | |
// | |
// byte[] encryptedMsg = new byte[]{}; | |
// try { | |
// encryptedMsg = AESCrypt.encrypt(secretKeySpec, ivBytes, byte_message); | |
// Log.e("encryptedMsg",new String(encryptedMsg)); | |
// | |
// }catch (GeneralSecurityException e){ | |
// Log.e("error on ecrypt",e.getLocalizedMessage()); | |
// } | |
// | |
// Log.i("_________","_________________________________________________________"); | |
// | |
// | |
// try { | |
// byte[] messageAfterDecrypt = AESCrypt.decrypt(secretKeySpec,ivBytes, encryptedMsg); | |
// | |
// //String s = new String(bytes); | |
// Log.e("messageAfterDecrypt",new String(messageAfterDecrypt)); | |
// }catch (GeneralSecurityException e){ | |
// Log.e("error on decyrpt",e.getLocalizedMessage()); | |
// } | |
// | |
//----------- EXAMPLE USING STRING AND PASSWORD -------------- | |
// String password = "pfdsa;fl[ad;]s'f;s';']"; | |
// String message = "hello world!"; | |
// byte[] byte_message = message.getBytes(Charset.forName("UTF-8")); | |
// | |
// String encryptedMsg = ""; | |
// try { | |
// encryptedMsg = AESCrypt.encrypt(password, message); | |
// Log.e("encryptedMsg",encryptedMsg); | |
// }catch (GeneralSecurityException e){ | |
// Log.e("error on ecrypt",e.getLocalizedMessage()); | |
// } | |
// | |
// Log.i("_________","_________________________________________________________"); | |
// | |
// | |
// try { | |
// String messageAfterDecrypt = AESCrypt.decrypt(password, encryptedMsg); | |
// | |
// //String s = new String(bytes); | |
// Log.e("messageAfterDecrypt",messageAfterDecrypt); | |
// }catch (GeneralSecurityException e){ | |
// Log.e("error on decyrpt",e.getLocalizedMessage()); | |
// } | |
/** | |
* Encrypt and decrypt messages using AES 256 bit encryption that are compatible with AESCrypt-ObjC and AESCrypt Ruby. | |
* <p/> | |
* Created by scottab on 04/10/2014. | |
*/ | |
public final class AESCrypt { | |
private static final String TAG = "AESCrypt"; | |
//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}; | |
//togglable log option (please turn off in live!) | |
public static boolean DEBUG_LOG_ENABLED = true; | |
/** | |
* 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(); | |
log("SHA-256 key ", key); | |
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES"); | |
return secretKeySpec; | |
} | |
/** | |
* 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); | |
log("message", message); | |
byte[] cipherText = encrypt(key, ivBytes, message.getBytes(CHARSET)); | |
//NO_WRAP is important as was getting \n at the end | |
String encoded = Base64.encodeToString(cipherText, Base64.NO_WRAP); | |
log("Base64.NO_WRAP", encoded); | |
return encoded; | |
} catch (UnsupportedEncodingException e) { | |
if (DEBUG_LOG_ENABLED) | |
Log.e(TAG, "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); | |
byte[] cipherText = cipher.doFinal(message); | |
log("cipherText", cipherText); | |
return cipherText; | |
} | |
/** | |
* 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); | |
log("base64EncodedCipherText", base64EncodedCipherText); | |
byte[] decodedCipherText = Base64.decode(base64EncodedCipherText, Base64.NO_WRAP); | |
log("decodedCipherText", decodedCipherText); | |
byte[] decryptedBytes = decrypt(key, ivBytes, decodedCipherText); | |
log("decryptedBytes", decryptedBytes); | |
String message = new String(decryptedBytes, CHARSET); | |
log("message", message); | |
return message; | |
} catch (UnsupportedEncodingException e) { | |
if (DEBUG_LOG_ENABLED) | |
Log.e(TAG, "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); | |
byte[] decryptedBytes = cipher.doFinal(decodedCipherText); | |
log("decryptedBytes", decryptedBytes); | |
return decryptedBytes; | |
} | |
private static void log(String what, byte[] bytes) { | |
if (DEBUG_LOG_ENABLED) | |
Log.d(TAG, what + "[" + bytes.length + "] [" + bytesToHex(bytes) + "]"); | |
} | |
private static void log(String what, String value) { | |
if (DEBUG_LOG_ENABLED) | |
Log.d(TAG, what + "[" + value.length() + "] [" + value + "]"); | |
} | |
/** | |
* 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); | |
} | |
private AESCrypt() { | |
} | |
} |
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the code likely and even comments are the same. like scottyab/AESCrypt