Currently having issues with the decryption of an AES hash.
When i encrypt using AES256 i get the following result (After base64 encoding)
07sKQfb9dN86XAMxFmVKHQAAAAAAAAAAAAAAAAAAAAA=
I believe my issue is with the AAAAAAAA etc. for some reason I think anyway the padding isn't being removed during decryption.
My code
public String encrypt(String key, String initVector, String value) throws Exception {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"), 0, initVector.getBytes().length);
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), 0, key.getBytes().length, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = new byte[32];
cipher.doFinal(value.getBytes(), 0, value.getBytes().length, encrypted, 0);
System.out.println("Base64: " + Base64.encode(encrypted));
System.out.println("Hex: " + bytesToHex(encrypted));
return Base64.encode(encrypted);
}
public String decrypt(String key, String initVector, String encrypted) {
try {
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"), 0, initVector.getBytes().length);
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), 0, key.getBytes().length, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] decrypted = new byte[64];
cipher.doFinal(Base64.decode(encrypted), 0, Base64.decode(encrypted).length, decrypted, 0);
return new String(decrypted);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
What i am expecting when i encode base64 07sKQfb9dN86XAMxFmVKHQ=
String i am encrypting: Test
Secret key: password12345678password12345678
byte[] decrypted = new byte[64];
you created a 64 byte array but the decrypted value may be shorter (Java doesn't use zero string terminator unlike C does). So you should not make assumption over the parameter length
try using
encrypted = cipher.doFinal(value.getBytes());
and
decrypted = cipher.doFinal(Base64.decode(encrypted));
Related
I want to encrypt the data in flutter using the AES cbc-128 algorithm. below is the java code for that i want to achieve the same functionality as below but in dart. i have tried
cryptography
dependency in flutter but the problem with that is that i want to use my own key in the algorithm as below in the java code. if you know any method for achieving this please let me know.
public static String Decrypt(String text, String key) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] keyBytes = new byte[16];
byte[] b = key.getBytes("UTF-8");
int len = b.length;
if (len > keyBytes.length)
len = keyBytes.length;
System.arraycopy(b, 0, keyBytes, 0, len);
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
IvParameterSpec ivSpec = new IvParameterSpec(keyBytes);
cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
BASE64Decoder decoder = new BASE64Decoder();
byte[] results = cipher.doFinal(decoder.decodeBuffer(text));
return new String(results, "UTF-8");
}
public static String Encrypt(String text, String key) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] keyBytes = new byte[16];
byte[] b = key.getBytes("UTF-8");
int len = b.length;
if (len > keyBytes.length)
len = keyBytes.length;
System.arraycopy(b, 0, keyBytes, 0, len);
SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
IvParameterSpec ivSpec = new IvParameterSpec(keyBytes);
cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);
byte[] results = cipher.doFinal(text.getBytes("UTF-8"));
BASE64Encoder encoder = new BASE64Encoder();
return encoder.encode(results);
}
Test Case
For the following input
plainText="This is plain text";
key="sahtojetrout2";
i want the encrypted result to be
encryptedText="8FmSMnDsFJVyNUXunhJLSmhFnRq89fl5DyTp0wdYfgk=";
which Topaco has written in an online editor you can check out that here Java Code. In flutter i have tried the program given at the Flutter site
You can do AES CBC-128 encryption in flutter with the help of crypt library. It supports the AES cbc encryption. The following sample code accepts key-string and plain-text as arguments and encrypts it as you have mentioned. You can pass your own key here. For AES-128, you need 128 bit key or 16 character string.
import 'package:encrypt/encrypt.dart';
void main() {
final key = "Your16CharacterK";
final plainText = "lorem ipsum example example";
Encrypted encrypted = encrypt(key, plainText);
String decryptedText = decrypt(key, encrypted);
print(decryptedText);
}
String decrypt(String keyString, Encrypted encryptedData) {
final key = Key.fromUtf8(keyString);
final encrypter = Encrypter(AES(key, mode: AESMode.cbc));
final initVector = IV.fromUtf8(keyString.substring(0, 16));
return encrypter.decrypt(encryptedData, iv: initVector);
}
Encrypted encrypt(String keyString, String plainText) {
final key = Key.fromUtf8(keyString);
final encrypter = Encrypter(AES(key, mode: AESMode.cbc));
final initVector = IV.fromUtf8(keyString.substring(0, 16));
Encrypted encryptedData = encrypter.encrypt(plainText, iv: initVector);
return encryptedData;
}
In the above example, the IV is created from the key itself to keep the code easy to read. Use random data for IV for better security. Referred article for flutter encryption.
Encryption done in java using AES and wanted to decrypt in Python, but the result is empty in python (no errors).
See the code before marking as duplicate. I want to detect problem in my code.
java encryption code:
public static String encrypt(String plainText) throws Exception {
KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
keyGenerator.init(128);
SecretKey secretKey = keyGenerator.generateKey();
String keyStr = Base64.encodeToString(secretKey.getEncoded(), Base64.NO_WRAP);
byte[] initVector = new byte[16];
(new Random()).nextBytes(initVector);
IvParameterSpec iv = new IvParameterSpec(initVector);
SecretKeySpec skeySpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] plainTextByte = plainText.getBytes();
byte[] encryptedByte = cipher.doFinal(plainTextByte);
byte[] messagebytes = new byte[initVector.length + encryptedByte.length];
System.arraycopy(initVector, 0, messagebytes, 0, 16);
System.arraycopy(encryptedByte, 0, messagebytes, 16, encryptedByte.length);
return Base64.encodeToString(messagebytes, Base64.NO_WRAP);
}
Python code
def decrypt(key, message):
"""
Input encrypted bytes, return decrypted bytes, using iv and key
"""
byte_array = message.encode("UTF-8")
iv = byte_array[0:16] # extract the 16-byte initialization vector
messagebytes = byte_array[16:] # encrypted message is the bit after the iv
cipher = AES.new(key.encode("UTF-8"), AES.MODE_CBC, iv)
decrypted_padded = cipher.decrypt(messagebytes)
decrypted = unpad(decrypted_padded)
return decrypted.decode("UTF-8");
I see that the Java is explicitly encoding the string as Base 64 at return Base64.encodeToString(messagebytes, Base64.NO_WRAP);
But i see that you are again encoding in python byte_array = message.encode("UTF-8") where in you will have to decode the encrypted message
# Standard Base64 Decoding
decodedBytes = base64.b64decode(encodedStr)
decodedStr = str(decodedBytes, "utf-8")
And only then Decrypt the decoded message.
Someone can help me with aes cbc algorithm? I have some method which return string more than 192 chars but I need to get 192!
I use next method. I've read a lot of articles but I don't get it how to do that.. Maybe someone have some instance how to resolve it?? I used to web aes encrypted http://www.cryptogrium.com/aes-encryption-online-ecb.html and I got 192 chars, but I can't do that with my method
private static byte[] iv = "0000000000000000".getBytes();
public static String encrypt(String content, String key) throws Exception {
byte[] input = content.getBytes("utf-8");
MessageDigest md = MessageDigest.getInstance("SHA-256");
byte[] thedigest = md.digest(key.getBytes("utf-8"));
SecretKeySpec skc = new SecretKeySpec(thedigest, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, skc, new IvParameterSpec(iv));
byte[] cipherText = new byte[cipher.getOutputSize(input.length)];
int ctLength = cipher.update(input, 0, input.length, cipherText, 0);
ctLength += cipher.doFinal(cipherText, ctLength);
return DatatypeConverter.printHexBinary (cipherText);
}
I am using AES/GCM/NoPadding encryption in java and (I am fairly new to it). If I understand it right GCM should recognize if encrypted message was manipulated, if so it should not decrypt it. As stated in this anwser:
The authentication TAG is an input to the decryption, if someone tampered with your associated data or with your encrypted data, GCM decryption will notice this and will not output any data (or return an error and you should discard the received data without processing it)
However, in my code, if I modify encrypted message (the message part or the tag part), I do not get any errors and the message will be decrypted (It will be different of course). I do not get any errors even when I provide different key, though message will be decrypted incorrectly...
What am I doing wrong? See the code below:
The util class:
public class CryptoUtils {
public static byte[] encrypt(byte[] key, byte[] iv, byte[] input) throws GeneralSecurityException {
try {
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
IvParameterSpec ivspec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivspec);
int outputLength = cipher.getOutputSize(input.length);
byte[] output = new byte[outputLength];
int outputOffset = cipher.update(input, 0, input.length, output, 0);
cipher.doFinal(output, outputOffset);
return output;
} catch (NoSuchAlgorithmException e) {
Timber.wtf(e);
}
return null;
}
public static byte[] decrypt(byte[] key, byte[] iv, byte[] encrypted) throws GeneralSecurityException {
try {
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
IvParameterSpec ivspec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivspec);
return cipher.doFinal(encrypted);
} catch (NoSuchAlgorithmException e) {
Timber.wtf(e);
}
return null;
}
}
The code that throws no errors:
byte[] key = getKey();
byte[] iv = generateIv();
byte[] message = "hello".getBytes();
byte[] encrypted = CryptoUtils.encrypt(key, iv, message);
//Split decrypted message into parts.
byte[] encryptedMessage = new byte[message.length];
System.arraycopy(encrypted, 0, encryptedMessage, 0, message.length);
byte[] tag = new byte[encrypted.length - message.length];
System.arraycopy(encrypted, message.length, tag, 0, tag.length);
//I am modifying the message here.
encryptedMessage[0] = 0;
// I am also modifying the key.
key[2] = 0;
//Put message and tag together.
byte[] toDecrypt = new byte[encrypted.length];
System.arraycopy(encryptedMessage, 0, toDecrypt, 0, encryptedMessage.length);
System.arraycopy(tag, 0, toDecrypt, encryptedMessage.length, tag.length);
//Still not getting any errors here.
byte[] decrypted = CryptoUtils.decrypt(key, iv, encryptedMessage);
byte[] decryptedMessage = new byte[message.length];
System.arraycopy(decrypted, 0, decryptedMessage, 0, message.length);
//Decrypted message is different than original.
Timber.d("Decrypted message: %s", new String(decryptedMessage));
I have a password string in my android application. I need to the send the password through the .net web service (i.e. end with .aspx) using the SOAP web service. Before sending the password i need to encrypt the password with AES 128 encryption with the custom key and IV.
They have a encrypt/decrypt tool in .net with the custom key and Iv. The tool ask a custom key with 16 digit and IV 8 digit. If give the string it generate the encrypting string. example
Example:
Key : 1234567812345678
IV : 12345678
String : android
Encrypted string : oZu5E7GgZ83Z3yoK4y8Utg==
I didn't have any idea how to do this in android. Need help.
A complete example may help you:
The encrypt/decrypt functions, using IV
public static byte[] encrypt(byte[] data, byte[] key, byte[] ivs) {
try {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
byte[] finalIvs = new byte[16];
int len = ivs.length > 16 ? 16 : ivs.length;
System.arraycopy(ivs, 0, finalIvs, 0, len);
IvParameterSpec ivps = new IvParameterSpec(finalIvs);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivps);
return cipher.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static byte[] decrypt(byte[] data, byte[] key, byte[] ivs) {
try {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
byte[] finalIvs = new byte[16];
int len = ivs.length > 16 ? 16 : ivs.length;
System.arraycopy(ivs, 0, finalIvs, 0, len);
IvParameterSpec ivps = new IvParameterSpec(finalIvs);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivps);
return cipher.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
You can use it as below :
String dataToEncryptDecrypt = "android";
String encryptionDecryptionKey = "1234567812345678";
String ivs = "12345678";
byte[] encryptedData = encrypt(dataToEncryptDecrypt.getBytes(), encryptionDecryptionKey.getBytes(),
ivs.getBytes());
// here you will get the encrypted bytes. Now you can use Base64 encoding on these bytes, before sending to your web-service
byte[] decryptedData = decrypt(encryptedData, encryptionDecryptionKey.getBytes(), ivs.getBytes());
System.out.println(new String(decryptedData));
I don't know the details of AES algorithm in use(ie mode & padding method), bit it should be roughly like this:
public static byte[] encrypt(byte[] data, byte[] key) {
try {
Cipher cipher = Cipher.getInstance("AES/CBC/ZeroBytePadding");
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
byte[] empty = new byte[16]; // For better security you should use a random 16 byte key!!!
IvParameterSpec ivps = new IvParameterSpec(empty);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivps);
return cipher.doFinal(data);
} catch (Exception e) {
// ...
}
return null;
}
Function above could be used like this:
String data = "android";
String key = "1234567812345678";
byte encrypted = encrypt(data.getbytes("UTF-8"), key.getbytes("UTF-8"));