Hi I'm using Bouncycastle library to create md5 hash from image byte array and client id string. But from Recognize.im API I'm still getting error invalid hash, is there anything wrong?
String myMd5(String myString, byte[] byteArray){
MD5Digest md5 = new MD5Digest();
md5.reset();
try {
md5.update(myString.getBytes("UTF-8"), 0 , myString.length());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
md5.update(byteArray, 0, byteArray.length);
byte[] digest = new byte[md5.getDigestSize()];
md5.doFinal(digest, 0);
StringBuffer sb = new StringBuffer();
for (int i = 0; i < digest.length; ++i) {
sb.append(Integer.toHexString((digest[i] & 0xFF) | 0x100)
.substring(1, 3));
}
return sb.toString();
}
Related
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.
I want to encrypt the string with XOR. The source text is in Cyrillic. After encrypting, I get the hieroglyphs, how can I fix it? I'll use the UTF-8 encoding.
String text = "Какой-нибудь русский текст"; // some cyrillic text
String sKey = LFSR(); // return string "10011010" for example
System.out.println("[PSP]: key: " + sKey); // output: 10011010
byte[] txt = text.getBytes(StandardCharsets.UTF_8);
byte[] key = sKey.getBytes(StandardCharsets.UTF_8);
byte[] res = new byte[txt.length];
for (int i = 0; i < txt.length; ++i) {
res[i] = (byte) (txt[i] ^ key[i % key.length]);
}
try {
System.out.println(new String(res, StandardCharsets.UTF_8));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
Output:
ފ���������������������������������������
I think it's because the byte values are negative.
I am using same MySQL table to store password from different program. One is written in Java and another is written in PHP.
I am saving password via PHP using this script:
encrypted_password= md5(md5('added_salt').md5(md5('plain_password')));
I need to encrypt password in Java using MD5 and salt like above. I write code in Java but it's output is different:
MessageDigest md = MessageDigest.getInstance("MD5");
String salts = "a,d,d,e,d,_,s,a,l,t";
String salttmps[] = salts.split(",");
byte salt[] = new byte[salttmps.length];
for (int i = 0; i < salt.length; i++) {
salt[i] = Byte.parseByte(salttmps[i]);
}
md.update(salt);
md.update(password.getBytes());
byte byteData[] = md.digest();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < byteData.length; i++) {
sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
}
password = sb.toString();
I need to correct Java code and generate output same as PHP.
If you could post an example of output in your question, it would be better to reproduce the algorithm.
I guess you should do something like this:
public static void main(String[] args) {
try {
System.out.println(md5(md5("added_salt"), md5("plain_password")));
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
public static String md5(String plainText) throws NoSuchAlgorithmException {
return md5(null, plainText);
}
public static String md5(String salt, String plainText)
throws NoSuchAlgorithmException {
MessageDigest md = MessageDigest.getInstance("MD5");
if (salt != null) {
md.update(salt.getBytes());
}
md.update(plainText.getBytes());
byte byteData[] = md.digest();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < byteData.length; i++) {
sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16)
.substring(1));
}
return sb.toString();
}
md5(md5("added_salt"), md5("plain_password")) returns 3bd9e544ab1a3d3485f07af38cc1b415
I am trying to write an encryption algorithm using RSA in Java, I am getting a
"javax.crypto.BadPaddingException: Data must start with zero"; I do not know what is this exception for.
This is the example I used here
and Here is my code; please help.
public byte[] getEncryptedValue(byte[] bytes, PublicKey key) {
try {
cipher.init(Cipher.ENCRYPT_MODE, key);
return blockCipher(bytes, Cipher.ENCRYPT_MODE);
} catch (Exception ex) {
Logger.getLogger(SecurityUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public byte[] getDecryptedValue(byte[] bytes, PrivateKey key) {
try {
cipher.init(Cipher.DECRYPT_MODE, key);
return blockCipher(bytes, Cipher.DECRYPT_MODE);
} catch (Exception ex) {
Logger.getLogger(SecurityUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
private byte[] append(byte[] prefix, byte[] suffix) {
byte[] toReturn = new byte[prefix.length + suffix.length];
System.arraycopy(prefix, 0, toReturn, 0, prefix.length);
System.arraycopy(suffix, 0, toReturn, prefix.length, suffix.length);
return toReturn;
}
private byte[] blockCipher(byte[] bytes, int mode) throws IllegalBlockSizeException, BadPaddingException {
byte[] scrambled = new byte[0];
byte[] toReturn = new byte[0];blocks (because of RSA)
int length = (mode == Cipher.ENCRYPT_MODE) ? 100 : 128;
int n = 0;
byte[] buffer = new byte[length];
for (int i = 0; i < bytes.length; i++) {
if ((i > 0) && (i % length == 0)) {
n = 0;
scrambled = cipher.doFinal(buffer);
toReturn = append(toReturn, scrambled);
}
buffer[i % length] = bytes[i];
n++;
}
***scrambled = cipher.doFinal(buffer, 0, n);*** <-- the exception is caught here
toReturn = append(toReturn, scrambled);
return toReturn;
}
The problem could be the data sent over the network using sockets may be corrupted due to some encoding problems. I had the same problem while developing a simple client/server chat program that encrypts/decrypts using asymmetric key the messages between the server and client and vise versa, instead of sending the message as a string, I sent it as a byte array which is the encrypted message.
check if keys are matching
check if data returned by getEncryptedValue are the same that you pass to getDecryptedValue
check corectness of loop in blockCipher method
I understand how it works but if I want to print out the MD5 as String how would I do that?
public static void getMD5(String fileName) throws Exception{
InputStream input = new FileInputStream(fileName);
byte[] buffer = new byte[1024];
MessageDigest hash = MessageDigest.getInstance("MD5");
int read;
do {
read = input.read(buffer);
if (read > 0) {
hash.update(buffer, 0, read);
}
} while (read != -1);
input.close();
}
You can get it writing less:
String hex = (new HexBinaryAdapter()).marshal(md5.digest(YOUR_STRING.getBytes()))
String input = "168";
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] md5sum = md.digest(input.getBytes());
String output = String.format("%032X", new BigInteger(1, md5sum));
or
DatatypeConverter.printHexBinary( MessageDigest.getInstance("MD5").digest("a".getBytes("UTF-8")))
Try this
StringBuffer hexString = new StringBuffer();
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] hash = md.digest();
for (int i = 0; i < hash.length; i++) {
if ((0xff & hash[i]) < 0x10) {
hexString.append("0"
+ Integer.toHexString((0xFF & hash[i])));
} else {
hexString.append(Integer.toHexString(0xFF & hash[i]));
}
}
You can also use Apache Commons Codec library.
This library includes methods public static String md5Hex(InputStream data) and public static String md5Hex(byte[] data) in the DigestUtils class.
No need to invent this yourself ;)
First you need to get the byte[] output of the MessageDigest:
byte[] bytes = hash.digest();
You can't easily print this though (with e.g. new String(bytes)) because it's going to contain binary that won't have good output representations. You can convert it to hex for display like this however:
StringBuilder sb = new StringBuilder(2 * bytes.length);
for (byte b : bytes) {
sb.append("0123456789ABCDEF".charAt((b & 0xF0) >> 4));
sb.append("0123456789ABCDEF".charAt((b & 0x0F)));
}
String hex = sb.toString();
Shortest way:
String toMD5(String input) {
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] raw = md.digest(input.getBytes());
return DatatypeConverter.printHexBinary(raw);
}
Just remember to handle the exception.
With the byte array, result from message digest:
...
byte hashgerado[] = md.digest(entrada);
...
for(byte b : hashgerado)
System.out.printf("%02x", Byte.toUnsignedInt(b));
Result (for example):
89e8a9f68ad3c4bba9b9d3581cf5201d
/**
* hashes:
* e7cfa2be5969e235138356a54bad7fc4
* 3c9ec110aa171b57bb41fc761130822c
*
* compiled with java 8 - 12 Dec 2015
*/
public static String generateHash() {
long r = new java.util.Random().nextLong();
String input = String.valueOf(r);
String md5 = null;
try {
java.security.MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
//Update input string in message digest
digest.update(input.getBytes(), 0, input.length());
//Converts message digest value in base 16 (hex)
md5 = new java.math.BigInteger(1, digest.digest()).toString(16);
}
catch (java.security.NoSuchAlgorithmException e) {
e.printStackTrace();
}
return md5;
}
FYI...
In certain situations this did not work for me
md5 = new java.math.BigInteger(1, digest.digest()).toString(16);
but this did
StringBuilder sb = new StringBuilder();
for (int i = 0; i < digest.length; i++) {
if ((0xff & digest[i]) < 0x10) {
sb.append("0").append(Integer.toHexString((0xFF & digest[i])));
} else {
sb.append(Integer.toHexString(0xFF & digest[i]));
}
}
String result = sb.toString();
Call hash.digest() to finish the process. It will return an array of bytes.
You can create a String from a byte[] using a String constructor, however if you want a hex string you'll have to loop through the byte array manually and work out the characters.
This is another version of #anything answer:
StringBuilder sb = new StringBuilder();
for (int i = 0; i < digest.length; i++) {
if ((0xff & digest[i]) < 0x10) {
sb.append("0").append(Integer.toHexString((0xFF & digest[i])));
} else {
sb.append(Integer.toHexString(0xFF & digest[i]));
}
}
String result = sb.toString();