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C# How to fix loss of data during file to binary to string to binary conversion

I read a file as binary, convert to hex string, convert back to binary, and write to a new file.
I expect a duplicate, but get a corrupted file.
I have been trying different ways to convert the binary into the hex string but can't seem to retain the entire file.
byte[] binary1 = File.ReadAllBytes(#"....Input.jpg");
string hexString = "";
int counter1 = 0;
foreach (byte b in binary1)
{
counter1++;
hexString += (Convert.ToString(b, 16));
}
List<byte> bytelist = new List<byte>();
int counter2 = 0;
for (int i = 0; i < hexString.Length/2; i++)
{
counter2++;
string ch = hexString.Substring(i*2,2);
bytelist.Add(Convert.ToByte(ch, 16));
}
byte[] binary2 = bytelist.ToArray();
File.WriteAllBytes(#"....Output.jpg", binary2);
Counter 1 and counter 2 should be the same count, but counter 2 is always about 10% smaller.
I want to get a duplicate file output that I could have transferred around via that string value.

Converting byte 10 will give a single char, and not 2 characters. Your convert back method (logically) build on 2 chars per byte.
this case works
byte[] binary1 = new byte[] { 100 }; // convert will result in "64"
and this case fails
byte[] binary1 = new byte[] { 10 }; // convert will result in "a"
I quick fixed your code, by padding with a "0" in case of a single char.
so working code:
byte[] binary1 = new byte[] { 100 };
string hexString = "";
int counter1 = 0;
foreach (byte b in binary1)
{
counter1++;
var s = (Convert.ToString(b, 16));
// new
if (s.Length < 2)
{
hexString += "0";
}
// end new
hexString += s;
}
List<byte> bytelist = new List<byte>();
int counter2 = 0;
for (int i = 0; i < hexString.Length / 2; i++)
{
counter2++;
string ch = hexString.Substring(i * 2, 2);
var item = Convert.ToByte(ch, 16);
bytelist.Add(item);
}
byte[] binary2 = bytelist.ToArray();
Please note, your code could use some refactoring, e.g. don't string concat in a loop and maybe check the Single Responsibility Principle.
Update, got it fixed, but there are better solutions here: How do you convert a byte array to a hexadecimal string, and vice versa?

Index and length must refer to a location within the string rand number

I'm trying to pass a random number to a character generator that will then return a random string with the length passed to it.
The StringToByteArray is as follows:
public static byte[] StringToByteArray(String hex)
{
int NumberChars = hex.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
return bytes;
}
If I pass a number manually to it like so:
byte[] strarr = Program.StringToByteArray(Program.GetUniqueKey(25));
It will work correctly and pass back a random string 25 chars long.
If I however pass a random number to it, it will pass the error "Index and length must refer to a location within the string"
int rndn = rnd.Next(20, 40);
byte[] strarr = Program.StringToByteArray(Program.GetUniqueKey(rndn));
What would be causing this?
GetUniqueKey:
public static string GetUniqueKey(int maxSize)
{
char[] chars = new char[304];
chars =
*long list of chars*
byte[] data = new byte[1];
using (RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider())
{
crypto.GetNonZeroBytes(data);
data = new byte[maxSize];
crypto.GetNonZeroBytes(data);
}
StringBuilder result = new StringBuilder(maxSize);
foreach (byte b in data)
{
result.Append(chars[b % (chars.Length)]);
}
return result.ToString();
}

StringToByteArray converts a hexadecimal string into an array of bytes.
Hexadecimal strings must have a length that is even because each byte is presented by two characters.
Here is what you can do to make sure that your random number is even:
int rndn = rnd.Next(10, 20) * 2;
This line is a replacement for:
int rndn = rnd.Next(20, 40);

Trying to reproduce PHP's pack("H*") function in C#

this is my code in C# :
public static String MD5Encrypt(String str, Boolean raw_output=false)
{
// Use input string to calculate MD5 hash
String output;
MD5 md5 = System.Security.Cryptography.MD5.Create();
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(str);
byte[] hashBytes = md5.ComputeHash(inputBytes);
// Convert the byte array to hexadecimal string
StringBuilder sb = new StringBuilder();
for (int i = 0; i < hashBytes.Length; i++)
{
sb.Append(hashBytes[i].ToString("x2"));
}
output = sb.ToString();
if (raw_output)
{
output = pack(output);
}
return output;
}
public static String pack(String S)
{
string MultiByte = "";
for (int i = 0; i <= S.Length - 1; i += 2)
{
MultiByte += Convert.ToChar(HexToDec(S.Substring(i, 2)));
}
return MultiByte;
}
private static int HexToDec(String hex)
{
//Int32.Parse(hexString, System.Globalization.NumberStyles.HexNumber);
return Convert.ToInt32(hex, 16);
}
To reproduce what is done in php by this way :
md5($str, true);
OR
pack('H*', md5( $str ));
I tried many things but can't get the same on the two sides in some cases of word.
For example, Trying this test on the string "8tv7er5j"
PHP Side :
9c36ad446f83ca38619e12d9e1b3c39e <= md5("8tv7er5j");
œ6­DoƒÊ8ažÙá³Ãž <= md5("8tv7er5j", true) or pack("H*", md5("8tv7er5j"))
C# Side :
9c36ad446f83ca38619e12d9e1b3c39e <= MD5Encrypt("8tv7er5j")
6­DoÊ8aÙá³Ã <= MD5Encrypt("8tv7er5j", true) or pack( MD5Encrypt("8tv7er5j") )
Why ? Encoding problem ?
EDIT 1 :
I have the good result, but bad encoded with this this function for pack() :
if ((hex.Length % 2) == 1) hex += '0';
byte[] bytes = new byte[hex.Length / 2];
for (int i = 0; i < hex.Length; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return bytes;
So, System.Text.Encoding.UTF8.GetString(bytes) give me :
�6�Do��8a���Þ
And System.Text.Encoding.ASCII.GetString(bytes)
?6?Do??8a??????
...

I encountered same scenario where I am in need of php's pack-unpack-md5 functions in C#. Most important was that I need to match out of all these 3 functions with php.
I created my own functions and then validated(verified) my output with functions at onlinephpfunctions.com. The output was same when I parsed with DefaultEncoding. FYI, I checked my application's encoding(Encoding.Default.ToString()) and it was System.Text.SBCSCodePageEncoding
Pack
private static string pack(string input)
{
//only for H32 & H*
return Encoding.Default.GetString(FromHex(input));
}
public static byte[] FromHex(string hex)
{
hex = hex.Replace("-", "");
byte[] raw = new byte[hex.Length / 2];
for (int i = 0; i < raw.Length; i++)
{
raw[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
return raw;
}
MD5
private static string md5(string input)
{
byte[] asciiBytes = Encoding.Default.GetBytes(input);
byte[] hashedBytes = MD5CryptoServiceProvider.Create().ComputeHash(asciiBytes);
string hashedString = BitConverter.ToString(hashedBytes).Replace("-", "").ToLower();
return hashedString;
}
Unpack
private static string unpack(string p1, string input)
{
StringBuilder output = new StringBuilder();
for (int i = 0; i < input.Length; i++)
{
string a = Convert.ToInt32(input[i]).ToString("X");
output.Append(a);
}
return output.ToString();
}
PS: User can enhance these functions with other formats

I guess that PHP defaults to Latin1 so the code should look like :
public static String PhpMd5Raw(string str)
{
var md5 = System.Security.Cryptography.MD5.Create();
var inputBytes = System.Text.Encoding.ASCII.GetBytes(str);
var hashBytes = md5.ComputeHash(inputBytes);
var latin1Encoding = System.Text.Encoding.GetEncoding("ISO-8859-1");
return latin1Encoding.GetString(hashBytes);
}

If you are going to feed the result as a key for HMAC-SHA1 hashing keep it as bytes[] and initialize the HMACSHA1 with the return value of this function: DO NOT convert it to a string and back to bytes, I have spent hours because of this mistake.
public static byte[] PackH(string hex)
{
if ((hex.Length % 2) == 1) hex += '0';
byte[] bytes = new byte[hex.Length / 2];
for (int i = 0; i < hex.Length; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return bytes;
}

I know this is an old question. I am posting my answer for anyone who might reach this page searching for it.
The following code is the full conversion of the pearl function pack("H*") to c#.
public static String Pack(String input)
{
input = input.Replace("-", " ");
byte[] hashBytes = new byte[input.Length / 2];
for (int i = 0; i < hashBytes.Length; i++)
{
hashBytes[i] = Convert.ToByte(input.Substring(i * 2, 2), 16);
}
return Encoding.UTF7.GetString(hashBytes); // for perl/php
}

I'm sorry. I didn't go with the questions completely. But if php code is as below,
$testpack = pack("H*" , "you value");
and if can't read the $testpack values(due to some non support format), then first do base64_encode as below and echo it.
echo base64_encode($testpack);
Then use Risky Pathak answer. For complete this answer I'll post his answer with some small modification like base 64 encoding etc.
var hex = "you value";
hex = hex.Replace("-", "");
byte[] raw = new byte[hex.Length / 2];
for (int i = 0; i < raw.Length; i++)
{
raw[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
var res = Convert.ToBase64String(raw);
Console.WriteLine(res);
Now if you compare both of values, those should be similar.
And all credit should go to the Risky Pathak answer.

The same in c# can be reached with Hex.Decode() method.
And bin2hex() in php is Hex.Encode().

Generating 40 char fingerprint for DSA

Is there a existing method within .NET Framework (C#) to generate a 40 char (public?) fingerprint as shown below, when you have P, Q, G, Y and X?
Or would anybody know on how to achieve this?
Fingerprint: 81F68001 29D928AD BEE41B78 AA862106 CAEAC892
EDIT:
here is an example of what i'm trying to do:
string P = "00F35DBCD6D4C296D2FE9118B659D02608B76FAC94BB58B10283F20390E2B259BAC602466162E9EF3E6A1590702CAE49B681A75A878E266F1AFAE0FA89DA5CA44A1551B517A3F80A9D6C630F9E7D239B437F7402DF8055069735894CD9D4708F8777B5E4F3E6A8B2D4EEE50DB2C96BA16D3C81FEB923697D649A8B7771B10E5B3F";
string Q = "00B5AF039839043410E04C35BDDB30679969EBAC8B";
string G = "00F300A68E54DE33A09001E28EC09F2ABF5DAF208774F2514D878D5587D870C91C6DE42B4705078C6F4438765050039C2950B6DE85AFC0D12A7A5C521782CB760918DF68F385A7F177DF50AA6BA0284090454106E422FCAE5390ADC00B859A433430019E970BFA614374DE1FB40C600345EF19DC01A122E4676C614DC29D3DC2FE";
string Y = "00A5317849AF22BA6498F1EF973158C8BDA848BEB074CB141E629C927B18F29C8CE99815001BAAB2931F339B5C52A79BC3DCB0C5962C302707BA6FF1807EEB91D751BA723BB7512C20689AC5E67A1B656CDFD1BA2D4F6A44308509486AA8754B47784FC4C03E546897200388656BA5834A2CC0E18E58454FF60C1BA5411D6F50FD";
i'm missing the code for this intermediate piece. how do i convert P, Q, G, Y into the fingerprint. I tried different approaches, but i'm unsuccessful generating the fingerprint i see in the application that i'm trying to recreate.
/* convert public key (bigIntKey) into fingerprint */
var bigIntHash = new BigInteger(SHA1.Create().ComputeHash(key.ToByteArray()));
byte[] hash = bigIntHash.ToByteArray();
if (hash.Length != 20)
{
throw new IndexOutOfRangeException();
}
for (int i = 0; i < 5; i++)
{
int lf = BitConverter.ToInt32(hash, i * 4);
Debug.Write(lf.ToString("X") + " ");
}
EDIT2:
i tried this, but that is not working
// switch P, Q, G, Y and separately to make it work.
byte[] pArr = StringToByteArray(P);
pArr = Tools.Endian.ReverseBytes(pArr);
byte[] qArr = StringToByteArray(Q);
qArr = Tools.Endian.ReverseBytes(qArr);
byte[] gArr = StringToByteArray(G);
gArr = Tools.Endian.ReverseBytes(gArr);
byte[] yArr = StringToByteArray(Y);
yArr = Tools.Endian.ReverseBytes(yArr);
byte[] xArr = StringToByteArray(X);
xArr = Tools.Endian.ReverseBytes(xArr);
byte[] arr = Combine(pArr, qArr, gArr, yArr);
DSACryptoServiceProvider dsa = new DSACryptoServiceProvider();
DSAParameters par = new DSAParameters();
par.P = pArr;
par.Q = qArr;
par.G = gArr;
par.Y = yArr;
par.X = xArr;
dsa.ImportParameters(par);
var xml = dsa.ToXmlString(true);
It will fail on the ImportParameter.
Thank you

You need to follow the OTR spec, which says the components of the key use MPI encoding, which it specifies as the length (32 bit big-endian) followed by the integer (big-endian, no leading zeros)
void Main()
{
string P = "00F35DBCD6D4C296D2FE9118B659D02608B76FAC94BB58B10283F20390E2B259BAC602466162E9EF3E6A1590702CAE49B681A75A878E266F1AFAE0FA89DA5CA44A1551B517A3F80A9D6C630F9E7D239B437F7402DF8055069735894CD9D4708F8777B5E4F3E6A8B2D4EEE50DB2C96BA16D3C81FEB923697D649A8B7771B10E5B3F";
string Q = "00B5AF039839043410E04C35BDDB30679969EBAC8B";
string G = "00F300A68E54DE33A09001E28EC09F2ABF5DAF208774F2514D878D5587D870C91C6DE42B4705078C6F4438765050039C2950B6DE85AFC0D12A7A5C521782CB760918DF68F385A7F177DF50AA6BA0284090454106E422FCAE5390ADC00B859A433430019E970BFA614374DE1FB40C600345EF19DC01A122E4676C614DC29D3DC2FE";
string Y = "00A5317849AF22BA6498F1EF973158C8BDA848BEB074CB141E629C927B18F29C8CE99815001BAAB2931F339B5C52A79BC3DCB0C5962C302707BA6FF1807EEB91D751BA723BB7512C20689AC5E67A1B656CDFD1BA2D4F6A44308509486AA8754B47784FC4C03E546897200388656BA5834A2CC0E18E58454FF60C1BA5411D6F50FD";
var publicKey =
ToMPI(HexToBytes(P))
.Concat(ToMPI(HexToBytes(Q)))
.Concat(ToMPI(HexToBytes(G)))
.Concat(ToMPI(HexToBytes(Y)))
.ToArray();
var fingerprint=BitConverter.ToString(SHA1.Create().ComputeHash(publicKey)).Replace("-","");
fingerprint.Dump();
}
byte[] ToMPI(byte[] data)
{
//Truncate leading 0 bytes
data = data.SkipWhile(b=>b==0).ToArray();
//Length prefix - 32 bit big-endian integer
var lenBytes=new byte[4];
lenBytes[0]=(byte)(data.Length>>24);
lenBytes[1]=(byte)(data.Length>>16);
lenBytes[2]=(byte)(data.Length>>8);
lenBytes[3]=(byte)(data.Length>>0);
return lenBytes.Concat(data).ToArray();
}
// from http://stackoverflow.com/questions/311165/how-do-you-convert-byte-array-to-hexadecimal-string-and-vice-versa
public static byte[] HexToBytes(String hex)
{
int NumberChars = hex.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
return bytes;
}

MSDN mentions what you need to do your job on this page.
Then, have a look at this answer from this SO page. The accepted answer gives the following code (and I quote):
var dsa = new DSACryptoServiceProvider();
var privateKey = dsa.ExportParameters(true); // private key
var publicKey = dsa.ExportParameters(false); // public key
I think you have everything you need to get you going.
CHEERS!

I've used this class to generate a OTR DSA key:
https://github.com/mohamedmansour/OTRLib/blob/master/Src/OTR/OTRUtilities/DSASigner.cs
Make the class public and call without constructor parameters.
var signer = new DSASigner();
var _des_key_object = signer.GetDSAKeyParameters();
Later reuse of the same key:
string _dsa_key_1_p = _des_key_object.GetHexParamP();
string _dsa_key_1_q = _des_key_object.GetHexParamQ();
string _dsa_key_1_g = _des_key_object.GetHexParamG();
string _dsa_key_1_x = _des_key_object.GetHexParamX();
// This can be a JSON for storing.
var keysArray = new string[] { _dsa_key_1_p, _dsa_key_1_q, _dsa_key_1_g, _dsa_key_1_x };
_des_key_object = new DSAKeyParams(_des_key_objectJson[0], _des_key_objectJson[1], _des_key_objectJson[2], _des_key_objectJson[3]);

How to convert a binary file to a string of zeroes and ones, and vice versa

I'm new to C# binary and I need to know something...
Read the exe
Translate it to string (eg. 10001011)
Modify the string
write it back to a new exe
I heard something about string.Join to convert binary to the string, but I couldn't understand very well.

To get the exe to a binary string, first read it into a byte array:
byte[] fileBytes = File.ReadAllBytes(inputFilename);
Then:
public static string ToBinaryString(byte[] array)
{
var s = new StringBuilder();
foreach (byte b in array)
s.Append(Convert.ToString(b, 2));
return s.ToString();
}
will get it to a binary string.
To turn your binary string back into a byte array:
public static byte[] FromBinaryString(string s)
{
int count = s.Length / 8;
var b = new byte[count];
for (int i = 0; i < count ; i++)
b[i] = Convert.ToByte(s.Substring(i * 8, 8), 2);
return b;
}
Finally, write the file:
File.WriteAllBytes(path, fileBytes);