Develop Reference

How to port MD5 signature code from Java to C#

I'm trying to port the following Java code to C#, but so far it still says that the signature is invalid.
private static String generateSignStr(Map<String, String> params, String key) {
StringBuilder sb = new StringBuilder();
params.entrySet().stream().sorted(Map.Entry.comparingByKey()).forEach(entry -> {
if (sb.length() > 0) {
sb.append('&');
}
sb.append(entry.getKey()).append('=');
sb.append(entry.getValue());
});
sb.append('&').append("api_secret")
.append('=').append(key);
return sb.toString();
}
private static String sign(String target) {
MessageDigest md;
try {
md = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
log.error("Fail to get MD5 instance");
return null;
}
md.update(target.getBytes());
byte[] dg = md.digest();
StringBuilder output = new StringBuilder(dg.length * 2);
for (byte dgByte : dg) {
int current = dgByte & 0xff;
if (current < 16) {
output.append("0");
}
output.append(Integer.toString(current, 16));
}
return output.toString();
}
private static string GenerateSign(Dictionary<string, object> query, string apiSecret)
{
var sb = new StringBuilder();
var queryParameterString = string.Join("&",
query.Where(kvp => !string.IsNullOrWhiteSpace(kvp.Value.ToString()))
.Select(kvp => $"{kvp.Key}={HttpUtility.UrlEncode(kvp.Value.ToString())}"));
sb.Append(queryParameterString);
if (sb.Length > 0)
{
sb.Append('&');
}
sb.Append("api_secret=").Append(apiSecret);
return sb.ToString();
}
private static string Sign(string source)
{
using var md5 = MD5.Create();
var sourceBytes = Encoding.UTF8.GetBytes(source);
var hash = md5.ComputeHash(sourceBytes);
return BitConverter.ToString(hash).Replace("-", string.Empty).ToLowerInvariant();
}
Edit:
This fixed it. However, it would be nice if someone knows a way to lexicographically sort the dictionary inside that method just like the Java code.
var #params = new Dictionary<string, object>
{
{ "api_key", _apiKey },
{ "req_time", now },
{ "op", "sub.personal" }
};
var javaSorted = #params.OrderBy(item => item.Key, StringComparer.Ordinal)
.ToDictionary(i => i.Key, i => i.Value);
var signature = Sign(GenerateSign(javaSorted, _apiSecret));

In GenerateSign method you can just create instance of SortedDictionary based on dictionary passed as parameter:
private static string GenerateSign(Dictionary<string, object> query, string apiSecret)
{
var sortedDict = new SortedDictionary<string, object>(query, StringComparer.Ordinal);
// rest of the method
}
Or you can do even better (note the important change from Dictionary to IDictionary):
private static string GenerateSign(IDictionary<string, object> query, string apiSecret)
{
query = new SortedDictionary<string, object>(query, StringComparer.Ordinal);
// rest of the method
}

Hooking into constructor of SecretKey and Mac not works Frida

Recently i tried to get value of secret key used to HMAC but i'm unable to hook into constructor. Here is my frida code:
var secretKey = Java.use("javax.crypto.spec.SecretKeySpec")
var mac = Java.use("javax.crypto.Mac")
mac.init.overload('java.security.Key').implementation = function (bytes) {
console.log("Mac init..")
return this.init(bytes)
}
secretKey.$init.overload('[B', 'java.lang.String').implementation = function (keyBytes, algo) {
console.log("SecretKey (" + algo + ") -> ")
return this.$init(keyBytes, algo)
}
secretKey.$init.overload('[B', 'int', 'int', 'java.lang.String').implementation = function (keyBytes, i, i2, algo) {
console.log("SecretKey (" + algo + ") -> ")
return this.$init(keyBytes, i, i2, algo)
}
But any of those hooks works. I don't know what can be a reason. I checked that this app using Enum to create Mac instance, and it's probably executed during runtime. That's how code looks:
public static void m26694i(Type type, String str) throws Exception {
synchronized (f21525a) {
if (f21526b == null) {
f21526b = type.getMacEnc(str);
}
}
}
#2
public enum Type {
KEY {
#Override
/* renamed from: getMac */
public Mac getMacEnc(String str) throws Exception {
return HmacUtil.m26681a(str);
}
},
FILE {
#Override
/* renamed from: getMac */
public Mac getMacEnc(String str) throws Exception {
Properties properties = new Properties();
InputStream inputStream = null;
try {
inputStream = MACManager.class.getResourceAsStream(str);
if (inputStream != null) {
properties.load(inputStream);
return HmacUtil.m26681a((String) properties.elements().nextElement());
}
throw new FileNotFoundException(str);
} finally {
if (inputStream != null) {
inputStream.close();
}
}
}
};
/* renamed from: getMac */
public abstract Mac getMacEnc(String str) throws Exception;
}
#3
public static Mac m26681a(String str) throws NoSuchAlgorithmException, InvalidKeyException {
SecretKeySpec secretKeySpec = new SecretKeySpec(str.getBytes(), "HmacSHA1");
Mac instance = Mac.getInstance("HmacSHA1");
instance.init(secretKeySpec);
return instance;
}
Any ideas how to hook into SecretKeySpec constructor?

Decryption result not consistent

I have two instances of my service that does the encryption and decryption running in cloud. The decryption fails sometimes with 'decryption failed' error. I guess this is because each instance has its own Aead instance. How can i solve this issue?
public class Utils {
private static final Logger log = LoggerFactory.getLogger(Utils.class);
private Aead aead;
private static Utils utils;
private Utils() {
try {
AeadConfig.register();
KeysetHandle keysetHandle = KeysetHandle.generateNew(AeadKeyTemplates.AES128_GCM);
aead = AeadFactory.getPrimitive(keysetHandle);
} catch (GeneralSecurityException e) {
log.error(String.format("Error occured: %s",e.getMessage())).log();
}
}
public static Utils getInstance() {
if(null == utils) {
utils = new Utils();
}
return utils;
}
public String encrypt(String text) throws GeneralSecurityException, UnsupportedEncodingException {
byte[] plainText = text.getBytes("ISO-8859-1");
byte[] additionalData = null;
byte[] cipherText = aead.encrypt(plainText,additionalData);
String output = Base64.getEncoder().encodeToString(cipherText);
return output;
}
public String decrypt(String text) throws GeneralSecurityException, UnsupportedEncodingException {
byte[] cipherText = Base64.getDecoder().decode(text);
byte[] additionalData = null;
byte[] decipheredData = aead.decrypt(cipherText,additionalData);
String output = new String(decipheredData,"ISO-8859-1");
return output;
}
#Test
public void encrypt() throws IOException, GeneralSecurityException {
String encryptedText = cryptographicUtils.encrypt("Hello World");
assertThat(encryptedText, Matchers.notNullValue());
}
#Test
public void decrypt() throws IOException, GeneralSecurityException {
String encryptedText = cryptographicUtils.encrypt("Hello 123456");
String decrypedText = cryptographicUtils.decrypt(encryptedText);
assertThat(decrypedText, Matchers.is("Hello 123456"));
}
I am getting consistent result if only one instance is running...

I will have to use the same keyset to encrypt and decrypt. I am able to resolve the issue by storing the keyset in a physical location and use it to create Aead instance. With this change all instances of my service able to decrypt string successfully

Looks like a thread safety issue. Try making the getInstance synchronized. Also, protect access to private Aead aead
Multiple threads can be altering the state of aead if you're not careful.
Consider a queue to do your work, or synchronize access to what is interacting with aead.

Java equivalent of C# RSACryptoServiceProvider

I am a newbie to Encryption algos and C# code.
I am trying to get some data which is being encrypted decrypted using RSA algo in C# code. Below is C# code. I can't find any similar library in Java, can you help me with getting a java equivalent for the same.
public byte[] Encrypt(byte[] data, string keyContainerName, bool doOaepPadding = false)
{
return DoCryptoTransformation(data, true, keyContainerName, doOaepPadding);
}
public byte[] Decrypt(byte[] data, string keyContainerName, bool doOaepPadding = false)
{
return DoCryptoTransformation(data, false, keyContainerName, doOaepPadding);
}
private byte[] DoCryptoTransformation(byte[] data, bool encryption, string keyContainerName,
bool doOaepPadding = false)
{
try
{
byte[] processedData;
RSACryptoServiceProvider.UseMachineKeyStore = true;
CspParameters cspParams = CreateCspParameters(keyContainerName);
using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspParams))
{
processedData = encryption ? rsa.Encrypt(data, doOaepPadding) : rsa.Decrypt(data, doOaepPadding);
}
return processedData;
}
catch (CryptographicException ex)
{
string message = string.Format("RsaCryptoProvider: Failed to {0} data.", encryption ? "encrypt" : "decrypt");
Logger.Error("{0}. Exception details: {1}", message, ex);
throw new CryptoProviderException(message, ex);
}
}
private static CspParameters CreateCspParameters(string keyContainerName)
{
CspParameters cspParams = new CspParameters();
cspParams.KeyContainerName = keyContainerName;
cspParams.Flags |= CspProviderFlags.UseExistingKey;
cspParams.Flags |= CspProviderFlags.UseMachineKeyStore;
return cspParams;
}
}
The methods used which I want to redefine implementation for in java:
var previousKey = _encryptionService.RsaDecrypt(Key, CoreSettings.Instance.KeyContainerName);
Thanks for help!

Firebase encrypted Chat app Runtime error. DatasnapShot to string?

I am trying to take in a string(message) and encrypt it then send it to the firebase database. Then when the app loads the data should be displayed to the user un-encrypted. So the encrypted string lies on the server/database.
Im getting nul pointer exception because it seems when you use snapshot it calls the default message constructor which does not contain the text which i called for.Essentially datasnapshot calls the default constructor which does not let me call the attributes of the object in the actual constructor. Is there anyway around this ?
Once the app request the Method that will request the messages from the database.The App crashes. I try to de-crypt the messages from a String of bytes before i display them... The messages however will no display and the app crashes
Here's a link to a screenshot
http://ibb.co/hqSJFv
This is the method that gets called when the sign in is successful and request the messages from the database and displays them(this worked until i messed with decrypting) I want to read from DB and decrypt then display the messages
//READ DECRYPT AND DISPLAY THE MESSAGES
mChildEventListener = new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
//called when new message is inserted into the list also
//triggered for every child message
EncryptoMessage encryptoMessage =
dataSnapshot.getValue(EncryptoMessage.class);
//get the text from the encryptomessage object store as string
String encryptedString = encryptoMessage.getText(); //value of
//encryptedString ends up empty
byte [] bytes = encryptedString.getBytes();
String str = null;
try {
str = new EncryptoMessage().decrypt(bytes);
} catch (Exception e) {
e.printStackTrace();
}
EncryptoMessage decryptedMessage = new EncryptoMessage();
decryptedMessage.setText(str);
mMessageAdapter.add(decryptedMessage);
}
This is the message from user input encrypted and stored as a string in DB. I coverted the btye[] to a string
//SEND CLICKED
// Send button sends a message and clears the EditText && Write to the
//Database
mSendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// TODO: Send messages on click
//get the message the user enters
String messageText = mMessageEditText.getText().toString();
byte[] codedtext = new byte[0];
try {
//take that message and encrypt it
//codedtext now equal to byte array of messageText
codedtext = new EncryptoMessage().encrypt(messageText);
} catch (Exception e) {
e.printStackTrace();
}
//change the encrypted bytes into a string and send to the
//database
String str = new String(codedtext, StandardCharsets.UTF_8);
//Create an EncryptoMessage object for the message the user
//enters
EncryptoMessage encryptoMessage = new EncryptoMessage(str,
mUsername, null);
//add the new message object to the EncryptoChat database
mMsgDatabaseReference.push().setValue(encryptoMessage);
// Clear input box
mMessageEditText.setText("");
}
});
This is Encrypted message object class(with encryption)
package com.google.firebase.david.encryptochat; //firebase API
import java.security.MessageDigest;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
//**************************************
//THis class is our message object
//*****************************************
public class EncryptoMessage {
private String text;
private String name;
private String photoUrl;
public EncryptoMessage() {
// Default constructor required for calls to
//DataSnapshot.getValue(User.class)
}
// The encrypto message constructor to create the object
public EncryptoMessage(String text, String name, String photoUrl) {
this.text = text;
this.name = name;
this.photoUrl = photoUrl;
}
//Copy constuctor
/* public EncryptoMessage(EncryptoMessage EncryptoMessageCopy){
this(EncryptoMessageCopy.getText(), EncryptoMessageCopy.getName());
}*/
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhotoUrl() {
return photoUrl;
}
public void setPhotoUrl(String photoUrl) {
this.photoUrl = photoUrl;
}
//Encryption of the messages
public byte[] encrypt(String message) throws Exception {
final MessageDigest md = MessageDigest.getInstance("md5");
final byte[] digestOfPassword = md.digest("HG58YZ3CR9"
.getBytes("utf-8"));
final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, iv);
final byte[] plainTextBytes = message.getBytes("utf-8");
final byte[] cipherText = cipher.doFinal(plainTextBytes);
return cipherText;
}
//Decrypt
public String decrypt(byte[] message) throws Exception {
//get the bytes if the string passing in
//byte [] bytes = message.getBytes();
final MessageDigest md = MessageDigest.getInstance("md5");
final byte[] digestOfPassword = md.digest("HG58YZ3CR9"
.getBytes("utf-8"));
final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
final Cipher decipher =
Cipher.getInstance("DESede/CBC/PKCS5Padding");
decipher.init(Cipher.DECRYPT_MODE, key, iv);
final byte[] plainText = decipher.doFinal(message);
return new String(plainText, "UTF-8");
}
}
This is the error i get at runtime just when i sign in and display messages it crashes also
FATAL EXCEPTION: main
Process: com.google.firebase.david.encryptochat, PID: 8733
java.lang.NullPointerException: Attempt to invoke virtual method 'byte[] java.lang.String.getBytes()' on a null object reference
at com.google.firebase.david.encryptochat.MainActivity$4.onChildAdded(MainActivity.java:238)