I am trying to decrypt a blowfish encrypted string with Bouncycastle in C#.
I am able to easily encrypt and decrypt my own string but, unfortunately, I have to decrypt a string that is generated by another system.
I AM able to recreate that same string with C# / Bouncycastle using the following but I have yet to decrypt it successfully.
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Paddings;
using Org.BouncyCastle.Crypto.Parameters;
...
static readonly Encoding Encoding = Encoding.UTF8;
public string BlowfishEncrypt(string strValue, string key)
{
try
{
BlowfishEngine engine = new BlowfishEngine();
PaddedBufferedBlockCipher cipher = new PaddedBufferedBlockCipher(engine);
KeyParameter keyBytes = new KeyParameter(Encoding.GetBytes(key));
cipher.Init(true, keyBytes);
byte[] inB = Encoding.GetBytes(strValue);
byte[] outB = new byte[cipher.GetOutputSize(inB.Length)];
int len1 = cipher.ProcessBytes(inB, 0, inB.Length, outB, 0);
cipher.DoFinal(outB, len1);
return BitConverter.ToString(outB).Replace("-", "");
}
catch (Exception)
{
return "";
}
}
Below is what I have for decryption at the moment. The line that fails with error "pad block corrupted" is cipher.DoFinal(out2, len2);
public string BlowfishDecrypt(string name, string keyString)
{
BlowfishEngine engine = new BlowfishEngine();
PaddedBufferedBlockCipher cipher = new PaddedBufferedBlockCipher(engine);
StringBuilder result = new StringBuilder();
cipher.Init(false, new KeyParameter(Encoding.GetBytes(keyString)));
byte[] out1 = Convert.FromBase64String(name);
byte[] out2 = new byte[cipher.GetOutputSize(out1.Length)];
int len2 = cipher.ProcessBytes(out1, 0, out1.Length, out2, 0);
cipher.DoFinal(out2, len2); //Pad block corrupted error happens here
String s2 = BitConverter.ToString(out2);
for (int i = 0; i < s2.Length; i++) {
char c = s2[i];
if (c != 0) {
result.Append(c.ToString());
}
}
return result.ToString();
}
Any idea what I might be doing wrong in BlowfishDecrypt()?
Note:
I converted the above (encrypt and decrypt) from a bouncycastle Java example I found somewhere; the encrypt works. The only difference I can see is that the Java example uses a StringBuffer where I use a StringBuilder.
Thank you, Artjom B!
byte[] out1 = Convert.FromBase64String(name);
Should have been
byte[] out1 = Hex.Decode(name);
From there, all I had to do was convert the Hex to a string.
Related
I have to request data from an external existing webservice written in C#.
This webservice requires some of the data to be encrypted (The connection uses an SSL connection, some of the data is aes encrypted)
On the php site openssl is used for decrypting.
The following settings are used on the c# site
(This are the default values for the AesCryptoServiceProvider):
Algorithm: AES
Padding: PKCS7
Mode: CBC
Keysize: 256
The padding for PKCS7 works as following:
01 If 1 byte is missing
02 02 If 2 bytes are missing
and so on
so this values are not added by the padding.
What am I doing wrong?
I've checked this with c#, php and ruby - the decrypted data starts with 255, 254
To reproduce use the following parameters:
data:1234567890123456
key: First1
salt(iv):Data
using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;
namespace crypto_test
{
class MainClass
{
public static void Main(string[] args)
{
bool running = true;
while (running)
{
Console.WriteLine("Enter data:");
var data = Console.ReadLine();
Console.WriteLine("Enter key:");
var key = Console.ReadLine();
Console.WriteLine("Enter iv:");
var iv = Console.ReadLine();
Console.WriteLine("Enter d for decode");
var decode = (Console.ReadLine() == "d");
string encoded=Crypt(data, key, iv, decode);
Console.WriteLine(encoded);
if (!decode)
{
encoded= Crypt(encoded, key, iv, true);
Console.WriteLine(encoded);
}
Console.WriteLine("quit to exit");
running = !(Console.ReadLine() == "quit");
}
}
public static string Crypt(string value, string password, string salt, bool decrypt)
{
DeriveBytes rgb = new Rfc2898DeriveBytes(password, Encoding.Unicode.GetBytes(salt));
SymmetricAlgorithm algorithm = new AesCryptoServiceProvider();
byte[] rgbKey = rgb.GetBytes(algorithm.KeySize >> 3);
byte[] rgbIV = rgb.GetBytes(algorithm.BlockSize >> 3);
Console.WriteLine("rbKey: size:{0} key:{1}", (algorithm.KeySize >> 3), GetHex(rgbKey));
Console.WriteLine("rgbIV: size:{0} key:{1}", (algorithm.BlockSize >> 3), GetHex(rgbIV));
ICryptoTransform transform = decrypt ? algorithm.CreateDecryptor(rgbKey, rgbIV) : algorithm.CreateEncryptor(rgbKey, rgbIV);
Console.WriteLine("Mode {0}", algorithm.Mode);
Console.WriteLine("PAdding {0}", algorithm.Padding);
using (MemoryStream buffer = new MemoryStream())
{
using (CryptoStream stream = new CryptoStream(buffer, transform, CryptoStreamMode.Write))
{
try
{
if (decrypt)
{
byte[] data = Convert.FromBase64String(value);
stream.Write(data,0,data.Length);
}
else
{
using (StreamWriter writer = new StreamWriter(stream, Encoding.Unicode))
{
writer.Write(value);
}
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
byte[] buff = buffer.ToArray();
if (decrypt)
{
return Encoding.Unicode.GetString(buff) + "\r\n" + GetHex(buff);
}
else
return Convert.ToBase64String(buff);
}
}
public static string GetHex(byte[] data)
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.Length; ++i)
sb.Append(data[i].ToString("X2"));
return sb.ToString();
}
}
}
I have not found an equivalent to Rfc2898DeriveBytes until now,
so I copied the key and iv
php
<?php
$salt='Data';
$pass='First1';
$data='1234567890123456';
$encrypted_base64='VKNd9Pi+cttaM6ne8pzAuFbH1U0gJiJ2Wlbbr1rU5z8vbIfAS6nb0/5py4p54aK7';
$encrypted=base64_decode($encrypted_base64);
$key = pack('H*', "30EE7F95F0EF4835F048A481424F2F52EE21B7CEB97F8CC437E5949DB53797D9");
$iv = pack('H*', "B29F5ECF7057065758102385509F0637");
$cipher='AES-256-CBC';
$decrypted = openssl_decrypt($encrypted,$cipher, $key,true,$iv);
for($i =0; $i<strlen($decrypted);++$i)
{
echo "char:" . ord($decrypted[$i])."<br/>";
}
echo $decrypted
?>
ruby:
require ('openssl')
require ('base64')
while true
enc_data='VKNd9Pi+cttaM6ne8pzAuFbH1U0gJiJ2Wlbbr1rU5z8vbIfAS6nb0/5py4p54aK7'
data = Base64.decode64(enc_data)
key_hex='30EE7F95F0EF4835F048A481424F2F52EE21B7CEB97F8CC437E5949DB53797D9'
iv_hex='B29F5ECF7057065758102385509F0637'
key = [key_hex].pack('H*')
iv = [iv_hex].pack('H*')
decipher = OpenSSL::Cipher::AES.new(256, :CBC)
decipher.decrypt
decipher.key = key
decipher.iv = iv
plain = decipher.update(data) + decipher.final
puts plain
puts plain.bytes
end
Good news, your decryption seems to work OK.
What you are seeing in the decrypted ciphertext is the byte order mark for UTF-16 LE, which is (incorrectly) indicated by Microsoft as Encoding.Unicode. You need to do either one off two things:
decode the text with a decoder that groks UTF-16 LE including byte order mark;
encode using much more reasonable UTF-8 encoding (in the C# code).
Personally I would put a strong preference on (2).
This is my very first attempt at cryptography and I am having trouble with porting the encryption from PHP to C#.
I had searched the internet for a working solution to my problem but everything I have tried does not work. I am getting different results between the two languages.
In PHP I have the following code:
function encrypt($Key, $strToEncrypt){
$md5Key = md5(pack("H*", $Key));
$md5Iv = md5($Key);
$block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$padding = $block - (strlen($strToEncrypt) % $block);
$strToEncrypt .= str_repeat(chr($padding), $padding);
$enc = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $md5Key, $strToEncrypt, MCRYPT_MODE_CBC, $md5Iv);
$enc2 = base64_encode($enc);
return $enc2;
}
and in C# the following code:
public string Encrypt(string strToEncrypt)
{
string ret;
var pKey = PackH(_appkey);
var md5Key = CalcMd5(pKey);
var iv = CalcMd5(_appkey);
var enc =Encoding.UTF8;
var eIv = enc.GetBytes(iv);
var eKey = enc.GetBytes(md5Key);
using (var rij = new RijndaelManaged { BlockSize = 256, KeySize = 256, IV = eIv, Key = eKey, Mode = CipherMode.CBC, Padding = PaddingMode.Zeros})
using (var memoryStream = new MemoryStream())
using (var cryptoStream = new CryptoStream(memoryStream, rij.CreateEncryptor(eKey, eIv), CryptoStreamMode.Write))
{
using (var sw = new StreamWriter(cryptoStream))
{
sw.Write(strToEncrypt);
}
ret = Convert.ToBase64String(memoryStream.ToArray());
}
return ret;
}
The C# Pack function:
protected byte[] PackH(string hex)
{
if ((hex.Length % 2) == 1) hex += '0';
var bytes = new byte[hex.Length / 2];
for (var i = 0; i < hex.Length; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return bytes;
}
And the C# CalcMd5 function:
protected string CalcMd5(string textToEnc)
{
var sB = new StringBuilder();
using (var mdHash = MD5.Create())
{
var cHash = mdHash.ComputeHash(Encoding.UTF8.GetBytes(textToEnc));
foreach (byte t in cHash)
{
sB.Append(t.ToString("x2"));
}
}
return sB.ToString();
}
I have another CalcMd5 function that takes in a byte[] (it is like the one above but does not have the GetBytes part).
The keys and the string that needs encrypting are the same both in PHP and C#:
The Key: "24acd2fcc7b20b8bd33ff45176f03061a09b729487e10d2dd38ab917" and
The string that I want to encode: "110114135AB96637711100"
In C# the result of the function is:"LHTqpxCJrONmbDdUFHyUZZUVf94z1RmSXWo85/wyEew=" while in PHP is: "5MkCjfs0vp2HSKdY5XPUAuV68YsrP31Q+ddZsd5p7Sc=".
I have tried modifying the padding mode in C#, also tried different methods found on the stackoverflow site but none of them works.
I have checked and the final key and Iv that are passed to the mcrypt function and RijndaelManaged function are the same and both have 32 byte size.
The oddly part is that the decryption functions are working very well (it is working to decrypt the PHP encrypted string with C# function and the other war around C# encrypted string is decrypted with the PHP function).
Could it be a problem with the encoding? Or maybe the padding? Or is there something else that I have overlooked?
The problem seems to be your padding, on PHP-side you are manually doing PKCS7-Padding:
$padding = $block - (strlen($strToEncrypt) % $block);
$strToEncrypt .= str_repeat(chr($padding), $padding);
And on C#-side you are using:
Padding = PaddingMode.Zeros
To fix this you could either modify the PHP-code by removing the above mentioned two lines since mcrypt() does automatically do ZeroBytePadding for you.
Or you could change the padding in C# to:
Padding = PaddingMode.PKCS7
I am trying to encrypt below base64 string in objective c .. Now i need to decrypt the output of below code in C# ... Please advice simplest way as i don't want to install any libs at server.
Please advice how can convert encripted string back to base64 using C# .
Thanks
My Objective c Code for encripting the base 64
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
SSCrypto *crypto;
NSString *password =#"abcdefghijklmnoqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnoqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyzabcdefghijklmnopqrstuvwzyz";
NSData *seedData1 = [password dataUsingEncoding:NSUTF8StringEncoding];
crypto = [[SSCrypto alloc] initWithSymmetricKey:seedData1];
NSString *base64String = #"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";
[crypto setClearTextWithString:base64String];
NSData *cipherText = [crypto encrypt:#"aes256"];
NSLog(#"Cipher text: '%#' using %#", [cipherText encodeBase64WithNewlines:NO], #"aes256");
NSLog(#" ");
[ pool release];
Below is my C# code for Decryption
public static string DecryptString(string base64StringToDecrypt, string passphrase)
{
//Set up the encryption objects
using (AesCryptoServiceProvider acsp = GetProvider(Encoding.Default.GetBytes(passphrase)))
{
byte[] RawBytes = Convert.FromBase64String(base64StringToDecrypt);
ICryptoTransform ictD = acsp.CreateDecryptor();
// TripleDES.
//RawBytes now contains original byte array, still in Encrypted state
//Decrypt into stream
MemoryStream msD = new MemoryStream(RawBytes, 0, RawBytes.Length);
CryptoStream csD = new CryptoStream(msD, ictD, CryptoStreamMode.Read);
//csD now contains original byte array, fully decrypted
//return the content of msD as a regular string
return (new StreamReader(csD)).ReadToEnd();
}
private static AesCryptoServiceProvider GetProvider(byte[] key)
{
AesCryptoServiceProvider result = new AesCryptoServiceProvider();
result.BlockSize = 128;
result.KeySize = 128;
result.Mode = CipherMode.CBC;
result.Padding = PaddingMode.PKCS7;
result.GenerateIV();
result.IV = new byte[] {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
byte[] RealKey = GetKey(key, result);
result.Key = RealKey;
// result.IV = RealKey;
return result;
}
private static byte[] GetKey(byte[] suggestedKey, SymmetricAlgorithm p)
{
byte[] kRaw = suggestedKey;
List<byte> kList = new List<byte>();
for (int i = 0; i < p.LegalKeySizes[0].MinSize; i += 8)
{
kList.Add(kRaw[(i / 8) % kRaw.Length]);
}
byte[] k = kList.ToArray();
return k;
}
Please advice if anything is missing or if i have done something gross wrong ..
I have lost more than 2 days in searching.
You can do this easily with the AesManaged class. See:
http://msdn.microsoft.com/en-us/library/system.security.cryptography.aesmanaged.aspx
I need tyhe dot net equivalent of the following code. Matter is, I am encrypting using Ruby on client side, here is the code.
The encoded string will be passed to a C# web service. That has to decrypt the string.
If someone can provide the dot net equivalent of this code, then it will be helpful.
require 'rubygems'
require 'ezcrypto'
require 'crypt/rijndael'
plaintext = '24.9195N 17.821E'
aes_key = Crypt::Rijndael.new('0123456789abcdef0123456789abcdef')
aes_cyphertext = aes_key.encrypt_string(plaintext)
print "\n"
print aes_cyphertext +"\n"
print Base64.encode64(aes_cyphertext)
print "\n"
print aes_key.decrypt_string(aes_cyphertext)
print "\n"
It's going to be something like this code shown below as a unit test. The first part does the encryption - the second half does the decryption.
Paste the code into a new MSTest unit test (Create New Test Project or add to an existing one).
The key and the iv are what you'll need to set accordingly.
//needed to convert from hex string
public static byte[] FromHexString(string hexString)
{
int NumberChars = hexString.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
bytes[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
return bytes;
}
[TestMethod]
public void Test()
{
string toEncryptString = "24.9195N 17.821E";
//initialise key and IV (note - all zero IV is not recommended!)
byte[] key = FromHexString("0123456789abcdef0123456789abcdef");
byte[] iv = FromHexString("00000000000000000000000000000000");
byte[] toEncrypt = System.Text.Encoding.UTF8.GetBytes(toEncryptString);
byte[] cipherBytes = null;
string cipherText = null;
//encrypt
using (System.Security.Cryptography.Rijndael r = new RijndaelManaged())
{
r.Key = key;
r.IV = iv;
using(System.Security.Cryptography.ICryptoTransform transform
= r.CreateEncryptor())
{
using (var mStream = new System.IO.MemoryStream())
{
using (var cStream =
new CryptoStream(mStream, transform, CryptoStreamMode.Write))
{
cStream.Write(toEncrypt, 0, toEncrypt.Length);
cStream.FlushFinalBlock();
cipherBytes = mStream.ToArray();
cipherText = Convert.ToBase64String(cipherBytes);
}
}
}
}
//decrypt
byte[] toDecrypt = Convert.FromBase64String(cipherText);
string decryptedString = null;
using (System.Security.Cryptography.Rijndael r = new RijndaelManaged())
{
r.Key = key;
r.IV = iv;
using(System.Security.Cryptography.ICryptoTransform transform2
= r.CreateDecryptor()) // <-- difference here
{
using (var mStream2 = new System.IO.MemoryStream())
{
using (var cStream2 =
new CryptoStream(mStream2, transform2, CryptoStreamMode.Write))
{
cStream2.Write(toDecrypt, 0, toDecrypt.Length);
cStream2.FlushFinalBlock();
decryptedString =
System.Text.Encoding.UTF8.GetString(mStream2.ToArray());
}
}
}
}
Assert.AreEqual(toEncryptString, decryptedString);
}
I am trying to make use of a REST API using C#. The API creator has provided sample libraries in PHP, Ruby and Java. I am getting hung up on one part of it where I need to generate an HMAC.
Here's how it is done in the sample libraries they have provided.
PHP
hash_hmac('sha1', $signatureString, $secretKey, false);
Ruby
digest = OpenSSL::Digest::Digest.new('sha1')
return OpenSSL::HMAC.hexdigest(digest, secretKey, signatureString)
Java
SecretKeySpec signingKey = new SecretKeySpec(secretKey.getBytes(), HMAC_SHA1_ALGORITHM);
Mac mac = null;
mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
mac.init(signingKey);
byte[] bytes = mac.doFinal(signatureString.getBytes());
String form = "";
for (int i = 0; i < bytes.length; i++)
{
String str = Integer.toHexString(((int)bytes[i]) & 0xff);
if (str.length() == 1)
{
str = "0" + str;
}
form = form + str;
}
return form;
Here's my attempt in C#. It is not working. UPDATE: The C# example below works just fine. I found out that the real problem was due to some cross-platform differences in newline characters in my signatureString.
var enc = Encoding.ASCII;
HMACSHA1 hmac = new HMACSHA1(enc.GetBytes(secretKey));
hmac.Initialize();
byte[] buffer = enc.GetBytes(signatureString);
return BitConverter.ToString(hmac.ComputeHash(buffer)).Replace("-", "").ToLower();
an extension to Vimvq1987's answer:
return hashValue.ToString(); doesn't produce the output you want/need. You have to convert the bytes in the array hashValue to their hex-string representation.
Can be as simple as return BitConverter.toString(hashValue); (prints upper-case letters A-F) or if you like it a bit more complex:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
public static string Encode(string input, byte[] key)
{
HMACSHA1 myhmacsha1 = new HMACSHA1(key);
byte[] byteArray = Encoding.ASCII.GetBytes(input);
MemoryStream stream = new MemoryStream(byteArray);
return myhmacsha1.ComputeHash(stream).Aggregate("", (s, e) => s + String.Format("{0:x2}",e), s => s );
}
static void Main(string[] args)
{
byte[] key = Encoding.ASCII.GetBytes("abcdefghijklmnopqrstuvwxyz");
string input = "";
foreach (string s in new string[] { "Marry", " had", " a", " little", " lamb" })
{
input += s;
System.Console.WriteLine( Encode(input, key) );
}
return;
}
}
}
which prints
3545e064fb59bc4bfc02b6e1c3d4925c898aa504
3249f4c8468d4d67f465937da05b809eaff22fdb
87baaadf5d096677f944015e53d283834eb1e943
6325376820c29a09e3ab30db000033aa71d6927d
54579b0146e2476595381d837ee38863be358213
and I get the exact same result for
<?php
$secretKey = 'abcdefghijklmnopqrstuvwxyz';
$signatureString = '';
foreach( array('Marry',' had',' a',' little',' lamb') as $s ) {
$signatureString .= $s;
echo hash_hmac('sha1', $signatureString, $secretKey, false), "\n";
}
edit: Dmitriy Nemykin suggested the following edit
public static string Encode(string input, byte[] key)
{
byte[] byteArray = Encoding.ASCII.GetBytes(input);
using(var myhmacsha1 = new HMACSHA1(key))
{
var hashArray = myhmacsha1.ComputeHash(byteArray);
return hashArray.Aggregate("", (s, e) => s + String.Format("{0:x2}",e), s => s );
}
}
which was rejected. But as James already pointed out in a comment to this answer at the very least the using statement is a good point.
This site has some pretty good examples across languages: http://jokecamp.wordpress.com/2012/10/21/examples-of-creating-base64-hashes-using-hmac-sha256-in-different-languages/
The c# implementation at the time of writing is:
private string CreateToken(string message, string secret)
{
secret = secret ?? "";
var encoding = new System.Text.ASCIIEncoding();
byte[] keyByte = encoding.GetBytes(secret);
byte[] messageBytes = encoding.GetBytes(message);
using (var hmacsha256 = new HMACSHA256(keyByte))
{
byte[] hashmessage = hmacsha256.ComputeHash(messageBytes);
return Convert.ToBase64String(hashmessage);
}
}
Try this:
http://msdn.microsoft.com/en-us/library/system.security.cryptography.hmacsha1.aspx
quick and dirty code:
public string Encode(string input, byte [] key)
{
HMACSHA1 myhmacsha1 = new HMACSHA1(key);
byte[] byteArray = Encoding.ASCII.GetBytes( input );
MemoryStream stream = new MemoryStream( byteArray );
byte[] hashValue = myhmacsha1.ComputeHash(stream);
return hashValue.ToString();
}