i'm having a problem during my project at school. what im trying to do is read plain text file and encrypt it using AES 128 which will give me a cipher text file, then i want to take the cipher file and convert it string to embed it into and image.
the AES class dealing with inputstream and the steganography dealing with string. If i extract the cipher text from image and save it to file to read it again using AES i get problem because there are some symbol which make a different between the file.
AES encryption method:
public static void encrypt(int keyLength, char[] password, InputStream input, OutputStream output){
if (keyLength != 128 && keyLength != 192 && keyLength != 256) {
throw new InvalidKeyLengthException(keyLength);
}
byte[] salt = generateSalt(SALT_LENGTH);
Keys keys = keygen(keyLength, password, salt);
Cipher encrypt = null;
try {
encrypt = Cipher.getInstance(CIPHER_SPEC);
encrypt.init(Cipher.ENCRYPT_MODE, keys.encryption);
} catch (NoSuchAlgorithmException | NoSuchPaddingException impossible) {
} catch (InvalidKeyException e) {
throw new StrongEncryptionNotAvailableException(keyLength);
}
byte[] iv = null;
try {
iv = encrypt.getParameters().getParameterSpec(IvParameterSpec.class).getIV();
} catch (InvalidParameterSpecException impossible) {
}
output.write(keyLength / 8);
output.write(salt);
output.write(keys.authentication.getEncoded());
output.write(iv);
byte[] buffer = new byte[BUFFER_SIZE];
int numRead;
byte[] encrypted = null;
while ((numRead = input.read(buffer)) > 0) {
encrypted = encrypt.update(buffer, 0, numRead);
if (encrypted != null) {
output.write(encrypted);
}
}
try {
encrypted = encrypt.doFinal();
} catch (IllegalBlockSizeException | BadPaddingException impossible) {
}
if (encrypted != null) {
output.write(encrypted);
}
}
Steganography encode method:
public boolean encode(BufferedImage img, String message) {
BufferedImage image = user_space(img);
image = add_text(image, message);
return (setImage(image));
}
If i can make steganography to return text file i think that would solve the problem.
what do you think?
Related
So I have some code in Java for encrypting and decrypting objects and I've been trying to do the same in C# so my server and client can decrypt and encrypt messages. I have gotten most of it to work except I am only missing the key parameters for Java.
#RequiredArgsConstructor
#Getter
public class EncryptedBytes {
private final byte[] data;
private final byte[] params;
private final String paramAlgorithm;
}
/**
* Encrypt object with password
*
* #param data Object to be encrypted
* #param secret Password to use for encryption
* #return Encrypted version of object
*/
public static EncryptedBytes encrypt(String data, SecretKey secret) throws InvalidKeyException {
try {
Cipher cipher = Cipher.getInstance(StaticHandler.AES_CIPHER_TRANSFORMATION);
cipher.init(Cipher.ENCRYPT_MODE, secret);
// properly encode the complete ciphertext
//logEncrypt(password, object);
byte[] encodedData = cipher.doFinal(data.getBytes(StaticHandler.CHARSET_FOR_STRING));
byte[] params = cipher.getParameters().getEncoded();
String paramAlgorithm = cipher.getParameters().getAlgorithm();
return new EncryptedBytes(encodedData, params, paramAlgorithm);
} catch (InvalidKeyException e) {
throw e;
} catch (NoSuchAlgorithmException | IllegalBlockSizeException | NoSuchPaddingException | BadPaddingException | IOException e) {
e.printStackTrace();
}
return null;
}
/**
* Decrypt data with secret
*
* #param encryptedBytes Object to be decrypted
* #param secret Password to use for decryption
* #return Decrypted version of object
*/
public static String decrypt(EncryptedBytes encryptedBytes, #NonNull SecretKey secret) throws InvalidKeyException {
try {
// get parameter object for password-based encryption
AlgorithmParameters algParams = AlgorithmParameters.getInstance(encryptedBytes.getParamAlgorithm());
if (algParams == null) throw new IllegalArgumentException("EncryptedBytes.Parameters are not valid");
// initialize with parameter encoding from above
algParams.init(encryptedBytes.getParams());
Cipher cipher = Cipher.getInstance(StaticHandler.AES_CIPHER_TRANSFORMATION);
cipher.init(Cipher.DECRYPT_MODE, secret, algParams);
return new String(cipher.doFinal(encryptedBytes.getData()), StaticHandler.CHARSET_FOR_STRING);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | BadPaddingException | IllegalBlockSizeException | IOException | InvalidAlgorithmParameterException e) {
e.printStackTrace();
}
return null;
}
Now in C# I have a very close implementation to the Java code above. I am only missing the params data for Java.
public class EncryptedBytes
{
public List<byte> data { get; }
[JsonProperty("params")]
[JsonPropertyName("params")]
public List<byte> keyParams { get; }
public string paramAlgorithm { get; }
public EncryptedBytes(IEnumerable<byte> data, IEnumerable<byte> keyParams, string paramAlgorithm)
{
this.data = data.ToList();
this.keyParams = keyParams.ToList();
this.paramAlgorithm = paramAlgorithm;
}
}
public static EncryptedBytes encrypt(AesCryptoServiceProvider aesCryptoServiceProvider, string plainText,
Encoding encoding)
{
if (encoding == null) encoding = StaticHandler.encoding;
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (aesCryptoServiceProvider.Key == null || aesCryptoServiceProvider.Key.Length <= 0)
throw new ArgumentNullException("Key");
if (aesCryptoServiceProvider.IV == null || aesCryptoServiceProvider.IV.Length <= 0)
throw new ArgumentNullException("IV");
ICryptoTransform transform = aesCryptoServiceProvider.CreateEncryptor();
return encrypt(transform, /* find paramater here */, plainText, encoding);
}
public static EncryptedBytes encrypt(ICryptoTransform transform, byte[] par, string plainText, Encoding encoding)
{
if (encoding == null) encoding = StaticHandler.encoding;
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException(nameof(plainText));
var encodedText = encoding.GetBytes(plainText);
var encryptedText =
transform.TransformFinalBlock(encodedText, 0, encodedText.Length);
return new EncryptedBytes(encryptedText, par, "AES");
}
public static string decrypt(EncryptedBytes encryptedBytes, AesCryptoServiceProvider aesCryptoServiceProvider, Encoding? encoding)
{
if (encoding == null) encoding = StaticHandler.encoding;
byte[] cipherText = encryptedBytes.data.ToArray();
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (aesCryptoServiceProvider.Key == null || aesCryptoServiceProvider.Key.Length <= 0)
throw new ArgumentNullException("Key");
if (aesCryptoServiceProvider.IV == null || aesCryptoServiceProvider.IV.Length <= 0)
throw new ArgumentNullException("IV");
// Declare the string used to hold
// the decrypted text.
ICryptoTransform transform = aesCryptoServiceProvider.CreateDecryptor();
var plaintext = encoding.GetString(transform.TransformFinalBlock(cipherText, 0, cipherText.Length));
return plaintext;
}
The main code in question is this:
encrypt
ICryptoTransform transform = aesCryptoServiceProvider.CreateEncryptor();
return encrypt(transform, /* find paramater here */, plainText, encoding);
and
decrypt
ICryptoTransform transform = aesCryptoServiceProvider.CreateDecryptor();
var plaintext = encoding.GetString(transform.TransformFinalBlock(cipherText, 0, cipherText.Length));
return plaintext;
I need a way to get the key parameters for Java to use to decrypt and to use the java parameters for decrypting in C# if needed.
Edit
Ok so I've got the encryption working. Now I need to get decryption working. The problem is that decryption uses the data sent by Java bytes and apparently NewtonsoftJSON can't deserialize it properly by using a byte[] so instead I use a sbyte[]. Thing is the decryption code requires a byte[] and I've tried casting and converting the sbyte[] to bytes by casting and Convert.ToByte() and none have worked. The closest I've gotten is casting the sbyte to byte however when running the new byte[] with transform.TransformFinalBlock(cipherText, 0, cipherText.Length) I get a malformed padding exception even though I am using PCKS7 padding on both (well specifically PCKS5 on Java)
I am converting my C# encryption code to Android.
I am facing issue like I am not able to encrypt the text as same as C#.
Below I copy paste both code.
Both are working code regarding using it you can use any password & any plain text .You will find both have different output.
C# CODE
System.security.Cryptography.RijndaelManaged AES = new System.Security.Cryptography.RijndaelManaged();
System.Security.Cryptography.MD5CryptoServiceProvider Hash_AES = new System.Security.Cryptography.MD5CryptoServiceProvider();
final MessageDigest Hash_AES = MessageDigest.getInstance("MD5");
String encrypted = "";
try {
byte[] hash = new byte[32];
byte[] temp = Hash_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass));
final byte[] temp = Hash_AES.digest(pass.getBytes("US-ASCII"));
Array.Copy(temp, 0, hash, 0, 16);
Array.Copy(temp, 0, hash, 15, 16);
AES.Key = hash;
AES.Mode = System.Security.Cryptography.CipherMode.ECB;
System.Security.Cryptography.ICryptoTransform DESEncrypter = AES.CreateEncryptor();
byte[] Buffer = System.Text.ASCIIEncoding.ASCII.GetBytes(input);
encrypted = Convert.ToBase64String(DESEncrypter.TransformFinalBlock(Buffer, 0, Buffer.Length));
} catch (Exception ex) {
}
return encrypted;
Here is my Android java code.
ANDROID JAVA CODE
private static String TRANSFORMATION = "AES/ECB/NoPadding";
private static String ALGORITHM = "AES";
private static String DIGEST = "MD5";
byte[] encryptedData;
public RijndaelCrypt(String password,String plainText) {
try {
//Encode digest
MessageDigest digest;
digest = MessageDigest.getInstance(DIGEST);
_password = new SecretKeySpec(digest.digest(password.getBytes()), ALGORITHM);
//Initialize objects
_cipher = Cipher.getInstance(TRANSFORMATION);
_cipher.init(Cipher.ENCRYPT_MODE, _password);
encryptedData = _cipher.doFinal(text);
} catch (InvalidKeyException e) {
Log.e(TAG, "Invalid key (invalid encoding, wrong length, uninitialized, etc).", e);
return null;
} catch (InvalidAlgorithmParameterException e) {
Log.e(TAG, "Invalid or inappropriate algorithm parameters for " + ALGORITHM, e);
return null;
} catch (IllegalBlockSizeException e) {
Log.e(TAG, "The length of data provided to a block cipher is incorrect", e);
return null;
} catch (BadPaddingException e) {
Log.e(TAG, "The input data but the data is not padded properly.", e);
return null;
}
return Base64.encodeToString(encryptedData,Base64.DEFAULT);
}
Should I need to use "US-ASCII" in pass or does it take it?
Use the same mode of operation: either ECB or CBC
Use the same character set: it's best to stick to "UTF-8"
Use the same key: in the C# code you're doubling the 128-bit key to 256 bits
When using CBC with a random IV, it is expected that the ciphertext differs for the same plaintext. The decryption is the operation that determines whether you succeeded.
Note that ECB is not semantically secure. Use CBC with a random IV. The IV doesn't have to be secret, so you can just prepend it to the ciphertext and slice it off before decryption.
It's better to use an authenticated mode like GCM or EAX or if it's not provided an encrypt-then-MAC scheme. It's hard to implement it correctly yourself so stick to some library that does this for you like RNCryptor.
I've been banging my head against the wall trying to figure out exactly how to format everything to decrypt this string in PHP that's been encrypted in a custom Java class.
Here's the relevent functions from the Java class. The "salt" variable is a class variable byte array set earlier:
public DesEncrypter(String passPhrase) {
try {
// Create the key
KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt,
iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES")
.generateSecret(keySpec);
ecipher = Cipher.getInstance(key.getAlgorithm());
dcipher = Cipher.getInstance(key.getAlgorithm());
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt,
iterationCount);
// Create the ciphers
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
} catch (java.security.InvalidAlgorithmParameterException e) {
} catch (java.security.spec.InvalidKeySpecException e) {
} catch (javax.crypto.NoSuchPaddingException e) {
} catch (java.security.NoSuchAlgorithmException e) {
} catch (java.security.InvalidKeyException e) {
}
}
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (javax.crypto.BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
}
return null;
}
public String decrypt(String str) {
try {
// Decode base64 to get bytes
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
// Decrypt
byte[] utf8 = dcipher.doFinal(dec);
// Decode using utf-8
return new String(utf8, "UTF8");
} catch( Exception ex) {
ex.printStackTrace(System.err);
}
return null;
}
And here's what I have so far in PHP (FYI, I'm using this encryption library in PHP https://github.com/phpseclib/phpseclib):
$app->get('/decrypt', function () use ($app) {
$data = '3aCRLRd3srA/QF4MQb0D+P==';
$salt = pack('nvc*', 0xB7, 0x9A, 0xC1, 0x34, 0x26, 0x89, 0xW3, 0x30);
$secret = "secret";
$keyLength = 16;
$cipher = new Crypt_DES(CRYPT_DES_MODE_CBC);
$cipher->setPassword($secret, 'pbkdf2', 'md5', $salt, $keyLength);
var_dump($cipher->decrypt($data));
});
Right now it's dumping out a bunch of binary, which I've tried base64_decoding, but that doesn't do anything either.
If key.getAlgorithm() is "DES" then you need to provide a fully specified Cipher name like "DES/CBC/PKCS5Padding".
You will also need to provide the IV if it is non-null. Usually the IV is prepended to the ciphertext.
You can get the IV with cipher.getIV() and set with $cipher->setIV('...');.
I am currently writing a program in Java that will accept strings from PHP and either encrypt or decrypt them depending on need. The mechanism of encryption is AES-256 and I am using the BouncyCastle API to do it. To ensure that there are fewer problems in transferring the data back and forth, I use Base64 to encode the strings. The problem I am experiencing is that randomly, I cannot decrypt a string-some string can be decrypted ok, others cannot. I found a great article here at stackoverflow I thought could help here.
But I could not really see how it could fit my circumstances (I am not an encryption expert). Here's my current code. Thanks for your help.
class AES {
private final BlockCipher AESCipher = new AESEngine();
private PaddedBufferedBlockCipher pbbc;
private KeyParameter key;
AES()
{
init();
}
private void init()
{
try
{
KeyGenerator kg = KeyGenerator.getInstance("AES");
kg.init(256);
SecretKey sk = kg.generateKey();
key=new KeyParameter(sk.getEncoded());
pbbc=new PaddedBufferedBlockCipher(AESCipher, new PKCS7Padding());
}
catch (Exception e)
{
//Take care of later
}
}
private byte[] processing(byte[] input, boolean encrypt)
throws DataLengthException, InvalidCipherTextException {
pbbc.init(encrypt, key);
byte[] output = new byte[pbbc.getOutputSize(input.length)];
int bytesWrittenOut = pbbc.processBytes(
input, 0, input.length, output, 0);
pbbc.doFinal(output, bytesWrittenOut);
return output;
}
private byte[] _encrypt(byte[] input)
throws DataLengthException, InvalidCipherTextException {
return processing(input, true);
}
private byte[] _decrypt(byte[] input)
throws DataLengthException, InvalidCipherTextException {
return processing(input, false);
}
public String Encrypt(String input)
{
try
{
byte[] ba = input.getBytes("UTF-8");
byte[] encr = _encrypt(ba);
byte[] encryptedByteValue = new Base64().encode(encr);
String encryptedValue = new String(encryptedByteValue);
return encryptedValue;//+" and decrypted is "+Decrypt(encryptedValue);
}
catch (Exception e)
{
return "ENCRYPT_ERROR "+e.getMessage();
}
}
public String Decrypt(String input)
{
try
{
byte[] decodedValue = new Base64().decode(input.getBytes());
byte[] retr = _decrypt(decodedValue);
return new String(retr, "UTF-8").replaceAll("\\u0000", "");
}
catch (Exception e)
{
return "DECRYPT_ERROR "+e.getMessage();
}
}
I figured out what the problem is, and it was two fold. This is what I wound up doing:
1) I was using cURL to communicate strings between Java and PHP and encoding encrypted text as Base64. Since the plus sign is valid in Base64 and not handled by cURL (at least by older versions), I would have mangled strings, thus leading to the error. I switched to hex encoding.
2) I had to remove carriage return (\r\n) characters from strings that went into the Java layer.
Hope this helps someone.
I am using this code: http://examples.javacodegeeks.com/core-java/crypto/encrypt-decrypt-file-stream-with-des for encrypting my zip files used in android app .It is working really fine with the zip files when I tried it using java code ,But when I tried same methods in Android app - It decrypts the file but file I get is corrupted and unable to open it.
Log:
04-19 10:58:25.711: W/System.err(6752): net.lingala.zip4j.exception.ZipException: zip headers not found. probably not a zip file
04-19 10:58:25.721: W/System.err(6752): at net.lingala.zip4j.core.HeaderReader.readEndOfCentralDirectoryRecord(HeaderReader.java:122)
And when I try to open the same file on Windows with winzip it displays:
Does not appear to be a valid archive file.
Update::
public class EncryptDecryptFileStreamWithDES {
private static Cipher ecipher;
private static Cipher dcipher;
// 8-byte initialization vector
private static byte[] iv = {
(byte)0xB2, (byte)0x12, (byte)0xD5, (byte)0xB2,
(byte)0x44, (byte)0x21, (byte)0xC3, (byte)0xC3
};
public static void call() {
try {
SecretKey key = KeyGenerator.getInstance("DES").generateKey();
AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
ecipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
dcipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
// encrypt(new FileInputStream("C:\\Users\\Admin\\Desktop\\zipped\\4.zip"), new FileOutputStream("C:\\Users\\Admin\\Desktop\\zipped\\4.dat"));
// decrypt(new FileInputStream("C:\\Users\\Admin\\Desktop\\zipped\\4.dat"), new FileOutputStream("C:\\Users\\Admin\\Desktop\\zipped\\4new.zip"));
//}
//catch (FileNotFoundException e) {
//System.out.println("File Not Found:" + e.getMessage());
//return;
}
catch (InvalidAlgorithmParameterException e) {
System.out.println("Invalid Alogorithm Parameter:" + e.getMessage());
return;
}
catch (NoSuchAlgorithmException e) {
System.out.println("No Such Algorithm:" + e.getMessage());
return;
}
catch (NoSuchPaddingException e) {
System.out.println("No Such Padding:" + e.getMessage());
return;
}
catch (InvalidKeyException e) {
System.out.println("Invalid Key:" + e.getMessage());
return;
}
}
public static void encrypt(InputStream is, OutputStream os) {
try {
call();
byte[] buf = new byte[1024];
// bytes at this stream are first encoded
os = new CipherOutputStream(os, ecipher);
// read in the clear text and write to out to encrypt
int numRead = 0;
while ((numRead = is.read(buf)) >= 0) {
os.write(buf, 0, numRead);
}
// close all streams
os.close();
}
catch (IOException e) {
System.out.println("I/O Error:" + e.getMessage());
}
}
public static void decrypt(InputStream is, OutputStream os) {
try {
call();
byte[] buf = new byte[1024];
// bytes read from stream will be decrypted
CipherInputStream cis = new CipherInputStream(is, dcipher);
// read in the decrypted bytes and write the clear text to out
int numRead = 0;
while ((numRead = cis.read(buf)) > 0) {
os.write(buf, 0, numRead);
}
// close all streams
cis.close();
is.close();
os.close();
}
catch (IOException e) {
System.out.println("I/O Error:" + e.getMessage());
}
}
}
This is the Class which I am using:
The problem is that you use different keys to encrypt and decrypt the file:
1) You call encrypt(..) from somewhere outside the EncryptDecryptFileStreamWithDES, which in its turn calls your call() method, which initializes new key:
SecretKey key = KeyGenerator.getInstance("DES").generateKey();
2) Then you call decrypt(..), which calls your call() method again and you get new SecretKey.
There is no such a problem in the example you used, there is an opposite order of these methods invocations.
To extend this example you need to hold the key between invocation of encrypt(..) and decrypt(..) and then initialize SecretKeySpec with the key stored:
byte[] keyBytes = KeyGenerator.getInstance("AES").getEncoded();
...
SecretKeySpec skeySpec = new SecretKeySpec(keyBytes, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
Here is a little bit more real-life example.
P.S. As it was mentioned, using DES algorithm is not the best idea, use AES instead.