Develop Reference

Hashing Results From C# and Java are Different

I'm trying to hash data "text" to be transferred from Java Service to C# Service.
I'm using SHA256 as a Hashing algorithm, but despite the values and the salt being the same the result doesn't.
Here is my C# snippet
public string Sign(string textToHash, string salt){
byte[] convertedHash = new byte[salt.Length / 2];
for (int i = 0; i < salt.Length / 2; i++)
convertedHash[i] = (byte)int.Parse(salt.Substring(i * 2, 2), NumberStyles.HexNumber);
HMAC hasher = new HMACSHA256(convertedHash);
string hexHash = "";
using (hasher)
{
byte[] hashValue = hasher.ComputeHash(Encoding.UTF8.GetBytes(textToHash));
foreach (byte b in hashValue)
{
hexHash += b.ToString("X2");
}
}
return hexHash;
}
And, here is the Java snippet
public static String sign(String textToHash, String salt){
byte[] convertedHash = new byte[salt.length() / 2];
for (int i = 0; i < salt.length() / 2; i++)
{
convertedHash[i] = (byte)Integer.parseInt(salt.substring(i * 2, i * 2 + 2),16);
}
String hashedText = null;
try {
MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(convertedHash);
byte[] bytes = md.digest(textToHash.getBytes(StandardCharsets.UTF_8));
StringBuilder sb = new StringBuilder();
for (byte aByte : bytes) {
sb.append(Integer.toString((aByte & 0xff) + 0x100, 16).substring(1));
}
hashedText = sb.toString();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return hashedText;
}
In Java, I also tried
convertedHash = salt.getBytes();
But I got different results also.
Tests:
salt = ABCDEFG
text = hashme
Result in C#
70B38047C28FFEDCF7275C428E65310671CADB65F11A5C9A8CFBB3CF52112BA3
Result in Java
a8bc36606aade01591a1d12c8b3c87aca1fe55def79740def03a90b49f2c6b7c
So, any help about why the results aren't the same.
Thanks in advance.

To mimic the Java hashing, I used SHA256Managed rather than HMACSHA256 in C#
public static string Sign(string data, string salt)
{
UTF8Encoding encoder = new UTF8Encoding();
SHA256Managed sha256hasher = new SHA256Managed();
byte[] convertedHash = new byte[salt.Length / 2];
for (int i = 0; i < salt.Length / 2; i++)
convertedHash[i] = (byte)int.Parse(salt.Substring(i * 2, 2), NumberStyles.HexNumber);
byte[] dataBytes = encoder.GetBytes(data);
byte[] bytes = new byte[convertedHash.Length + dataBytes.Length];
Array.Copy(convertedHash, bytes, convertedHash.Length);
Array.Copy(dataBytes, 0, bytes, convertedHash.Length, dataBytes.Length);
byte[] hashedBytes = sha256hasher.ComputeHash(bytes);
return hashedBytes.Aggregate("", (current, t) => current + t.ToString("X2"));
}
HMACSHA256 is not a pure SHA-256.

How to use XOR to develop a ​OTPInputStream​ in Java

I want to develop a ​OTPInputStream ​in Java that extends the ​InputStream ​and takes another input stream of key data and provides a stream encrypting / decrypting input stream.I need to develop a test program to show the use of ​OTPInputStream​ that uses XOR and arbitrary data.
I tried with this code but I have problem that is
java.io.FileInputStream cannot be cast to java.lang.CharSequence
What should I do here?
public class Bitwise_Encryption {
static String file = "" ;
static String key = "VFGHTrbg";
private static int[] encrypt(FileInputStream file, String key) {
int[] output = new int[((CharSequence) file).length()];
for(int i = 0; i < ((CharSequence) file).length(); i++) {
int o = (Integer.valueOf(((CharSequence) file).charAt(i)) ^ Integer.valueOf(key.charAt(i % (key.length() - 1)))) + '0';
output[i] = o;
}
return output;
}
private static String decrypt(int[] input, String key) {
String output = "";
for(int i = 0; i < input.length; i++) {
output += (char) ((input[i] - 48) ^ (int) key.charAt(i % (key.length() - 1)));
}
return output;
}
public static void main(String args[]) throws FileNotFoundException {
FileInputStream file = new FileInputStream("directory");
encrypt(file,key);
//decrypt();
int[] encrypted = encrypt(file,key);
System.out.println("Encrypted Data is :");
for(int i = 0; i < encrypted.length; i++)
System.out.printf("%d,", encrypted[i]);
System.out.println("");
System.out.println("---------------------------------------------------");
System.out.println("Decrypted Data is :");
System.out.println(decrypt(encrypted,key));
}
}

Think what you want is just file.read() and file.getChannel().size() to read one character at a time and get the size of the file
Try something like this:
private static int[] encrypt(FileInputStream file, String key) {
int fileSize = file.getChannel().size();
int[] output = new int[fileSize];
for(int i = 0; i < output.length; i++) {
char char1 = (char) file.read();
int o = (char1 ^ Integer.valueOf(key.charAt(i % (key.length() - 1)))) + '0';
output[i] = o;
}
return output;
}
Will have to do some error handling because file.read() will return -1 if the end of the file has been reached and as pointed out reading one byte at a time is lot of IO operations and can slow down performance. You can keep the data in a buffer and read it another way like this:
private static int[] encrypt(FileInputStream file, String key) {
int fileSize = file.getChannel().size();
int[] output = new int[fileSize];
int read = 0;
int offset = 0;
byte[] buffer = new byte[1024];
while((read = file.read(buffer)) > 0) {
for(int i = 0; i < read; i++) {
char char1 = (char) buffer[i];
int o = (char1 ^ Integer.valueOf(key.charAt(i % (key.length() - 1)))) + '0';
output[i + offset] = o;
}
offset += read;
}
return output;
}
This will read in 1024 bytes at a time from the file and store it in your buffer, then you can loop through the buffer to do your logic. The offset value is to store where in our output the current spot is. Also you will have to make sure that i + offset doesn't exceed your array size.
UPDATE
After working with it; i decided to switch to Base64 Encoding/Decoding to remove non-printable characters:
private static String encrypt(InputStream file, String key) throws Exception {
int read = 0;
byte[] buffer = new byte[1024];
try(ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
while((read = file.read(buffer)) > 0) {
baos.write(buffer, 0, read);
}
return base64Encode(xorWithKey(baos.toByteArray(), key.getBytes()));
}
}
private static String decrypt(String input, String key) {
byte[] decoded = base64Decode(input);
return new String(xorWithKey(decoded, key.getBytes()));
}
private static byte[] xorWithKey(byte[] a, byte[] key) {
byte[] out = new byte[a.length];
for (int i = 0; i < a.length; i++) {
out[i] = (byte) (a[i] ^ key[i%key.length]);
}
return out;
}
private static byte[] base64Decode(String s) {
return Base64.getDecoder().decode(s.trim());
}
private static String base64Encode(byte[] bytes) {
return Base64.getEncoder().encodeToString(bytes);
}
This method is cleaner and doesn't require knowing the size of your InputStream or do any character conversions. It reads your InputStream into an OutputStream to do the Base64 Encoding as well to remove non printable characters.
I have tested this and it works both for encrypting and decrypting.
I got the idea from this answer:
XOR operation with two strings in java

How to create an audio wave in JavaFX?

I would like to get an Audio wave plot using Chart Area in JavaFX. Unfortunately, I am not clear how to do, what are the values ​​to be extracted from the sound to assign to x-axis and y-axis?
I tried to read other posts, but I found nothing on javafx.
You can help me?
Sample Image:
Below is the code that extract the waveform .
I'm pulling out the right parameters for my scope?
How can I use it to print the graph with JavaFX?
public class SimpleWaveformExtractor implements WaveformExtractor {
private static final int DEFAULT_BUFFER_SIZE = 32768;
#Override
public double[] extract(File inputFile) {
AudioInputStream in = null;
try {
in = AudioSystem.getAudioInputStream(inputFile);
} catch (Exception e) {
System.out.println("Cannot read audio file");
return new double[0];
}
AudioFormat format = in.getFormat();
byte[] audioBytes = readBytes(in);
int[] result = null;
if (format.getSampleSizeInBits() == 16) {
int samplesLength = audioBytes.length / 2;
result = new int[samplesLength];
if (format.isBigEndian()) {
for (int i = 0; i < samplesLength; ++i) {
byte MSB = audioBytes[i * 2];
byte LSB = audioBytes[i * 2 + 1];
result[i] = MSB << 8 | (255 & LSB);
}
} else {
for (int i = 0; i < samplesLength; i += 2) {
byte LSB = audioBytes[i * 2];
byte MSB = audioBytes[i * 2 + 1];
result[i / 2] = MSB << 8 | (255 & LSB);
}
}
} else {
int samplesLength = audioBytes.length;
result = new int[samplesLength];
if (format.getEncoding().toString().startsWith("PCM_SIGN")) {
for (int i = 0; i < samplesLength; ++i) {
result[i] = audioBytes[i];
}
} else {
for (int i = 0; i < samplesLength; ++i) {
result[i] = audioBytes[i] - 128;
}
}
}
return ArraysHelper.normalize(result);
}
private byte[] readBytes(AudioInputStream in) {
byte[] result = new byte[0];
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
try {
int bytesRead = 0;
do {
bytesRead = in.read(buffer);
result = ArrayUtils.addAll(result, buffer);
} while (bytesRead != -1);
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
}
this is the interface:
public interface WaveformExtractor {
double[] extract(File in);
}
This is the code that return the array of double:
private double[] extractWaveform(File file) throws IOException, UnsupportedAudioFileException {
return new WavFileExtractor().extract(file);
}

Decrypt text that was encrypted with symmetric cipher JAVA

I am trying to decrypt a text file.I have the original text and the encrypted one ,plus the encryption code itself.I think it is similar to XOR
cipher but I am not sure.I read about Known-plaintext attack but wasn't able to find good example to try and implement in my task.
I know java is using linear congruential formula and that I can use brute force to find the key for the decryption.
In my code I was trying to play with the seed .I tried to compare to strings each time after decryption was made but I did not succeed.Any help would be much appreciated.
public class test {
public static int KEY = 0; // enter code here
public static Random _rand = new Random(KEY);
private static int counter = 0;
public static void main(String[] args) throws Exception {
init_seed();
simple_test0();
decMSG();
}
public static void init_seed() {
_rand = new Random(KEY);
}
public static void simple_test0() {
String [] msg = {"Iron Beast"};
int len = msg.length;
String[] msg_enc = new String[len];
init_seed();
for(int i = 0; i < len; i++) {
msg_enc[i] = enc(msg[i]);
}
init_seed();
System.out.println(_rand);
for(int i=0;i<len;i++) {
String se2 = enc(msg_enc[i]);
System.out.println(i+") orig: "+msg[i]+"\n"+" enc(orig): "+msg_enc[i]+"\n"+" enc(enc(orig)): "+se2);
System.out.println();
}
}
public static String enc(String msg) {
String ans ="";
for(int i = 0; i < msg.length(); i++) {
char c = msg.charAt(i);
int s = c;
int rd = _rand.nextInt() % (256*256);
int s2 = s ^ rd;
char c2 = (char) (s2);
ans += c2;
}
return ans;
}
public static void decMSG() throws Exception {
boolean ans = false;
String file_name = "msg";
String msg = "first text line";
FileReader fr = new FileReader(file_name);
BufferedReader is = new BufferedReader(fr);
String s = is.readLine();
int key = 0;
while(ans == false ) {
KEY =key;
s = enc(s);
if(msg.equals(s)) {
System.out.println(s + "\t" + KEY);
ans = true;
counter++;
}
_rand = new Random(key);
System.out.println( KEY);
if(key > 10000000) {
key=0;
}
key++;
}
System.out.println(counter);
is.close();
fr.close();
}
}

Hex to ASCII showing different result to correct PHP implementaiton

I needed a method that would convert hex to ascii, and most seem to be a variation of the following:
public String hexToAscii(String hex) {
StringBuilder sb = new StringBuilder();
StringBuilder temp = new StringBuilder();
for(int i = 0; i < hex.length() - 1; i += 2){
String output = hex.substring(i, (i + 2));
int decimal = Integer.parseInt(output, 16);
sb.append((char)decimal);
temp.append(decimal);
}
return sb.toString();
}
The idea is to look at
hexToAscii("51d37bdd871c9e1f4d5541be67a6ab625e32028744d7d4609d0c37747b40cd2d");
If I print the result out, I get
-Í#{t7?`Ô×D?2^b«¦g¾AUM??Ý{ÓQ.
This is not the result I am needing though. A friend got the correct result in PHP which was the string reverse of the following:
QÓ{݇žMUA¾g¦«b^2‡D×Ô`7t{#Í-
There are clearly characters that his hexToAscii function is encoding whereas mine is not.
Not really sure why this is the case, but how can I implement this version in Java?

Assuming your input string is in, I would use a method like this
public static byte[] decode(String in) {
if (in != null) {
in = in.trim();
List<Byte> bytes = new ArrayList<Byte>();
char[] chArr = in.toCharArray();
int t = 0;
while (t + 1 < chArr.length) {
String token = "" + chArr[t] + chArr[t + 1];
// This subtracts 128 from the byte value.
int b = Byte.MIN_VALUE
+ Integer.valueOf(token, 16);
bytes.add((byte) b);
t += 2;
}
byte[] out = new byte[bytes.size()];
for (int i = 0; i < bytes.size(); ++i) {
out[i] = bytes.get(i);
}
return out;
}
return new byte[] {};
}
And then you could use it like this
new String(decode("51d37bdd871c9e1f4d5541be67a6ab625e"
+"32028744d7d4609d0c37747b40cd2d"))

How about trying like this:
public static void main(String[] args) {
String hex = "51d37bdd871c9e1f4d5541be67a6ab625e32028744d7d4609d0c37747b40cd2d";
StringBuilder output = new StringBuilder();
for (int i = 0; i < hex.length(); i+=2) {
String str = hex.substring(i, i+2);
output.append((char)Integer.parseInt(str, 16));
}
System.out.println(output);
}