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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?

How to XOR a MD5 hash and return a 32 character string?

How do I further encrypt a MD5 hash by XOR'ing it with a string of variable size (not bigger than 32 characters) ?
I would like the result of the XOR to be a 32 character string as well.
What i have tried so far is:
convert the md5 string to binary
convert second string to binary
pad second binary with 0's (to the left) until both binaries are of equal length
iterate the binary representations and XOR them
convert the XOR'ed result to a string
The approach may be wrong, im not sure how to do it. My problem is, when converting the result of the XOR, it is not a 32 character long string, as I would like it to be.
Sample code (equal length strings in this case):
class Program
{
static void Main(string[] args)
{
var md51 = ToBinary(ConvertToByteArray(CalculateMD5Hash("Maaa"), Encoding.ASCII));
var md52 = ToBinary(ConvertToByteArray(CalculateMD5Hash("Moo"), Encoding.ASCII));
List<int> xoredResult = new List<int>();
for (int i = 0; i < md51.Length; i++)
{
var string1 = md51[i];
var string2 = md52[i];
var xor = string1 ^ string2;
xoredResult.Add(xor);
}
var resultingString = string.Join("", xoredResult);
Console.WriteLine(resultingString.Length);
var data = GetBytesFromBinaryString(resultingString);
var text = Encoding.ASCII.GetString(data);
}
public static byte[] ConvertToByteArray(string str, Encoding encoding)
{
return encoding.GetBytes(str);
}
public static String ToBinary(Byte[] data)
{
return string.Join("", data.Select(byt => Convert.ToString(byt, 2).PadLeft(8, '0')));
}
public static Byte[] GetBytesFromBinaryString(String binary)
{
var list = new List<Byte>();
for (int i = 0; i < binary.Length; i += 8)
{
String t = binary.Substring(i, 8);
list.Add(Convert.ToByte(t, 2));
}
return list.ToArray();
}
public static string CalculateMD5Hash(string input)
{
// step 1, calculate MD5 hash from input
MD5 md5 = System.Security.Cryptography.MD5.Create();
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
byte[] hash = md5.ComputeHash(inputBytes);
// step 2, convert byte array to hex string
StringBuilder sb = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
sb.Append(hash[i].ToString("X2"));
}
return sb.ToString();
}
}

xoring a string with what is essentially random bytes is not guaranteed to give you a valid string as a output. Your var text = Encoding.ASCII.GetString(data); is likely failing because you are passing it a non valid string in byte form. You must use something like var text = Convert.ToBase64String(data) to be able to represent the random data without loss of information in the process.

C# - Get Integer Byte Array in String

I have a random integer value which I need to represent in String as a Byte array. For example:
int value = 32;
String strValue = getStringByteArray(value);
Console.WriteLine(strValue); // should write: " \0\0\0"
If value = 11 then getStringByteArray(value) shuld return "\v\0\0\0".
If value = 13 then getStringByteArray(value) shuld return "\r\0\0\0".
And so on.
Any idea on how to implement the method getStringByteArray(int value) in C#?
UPDATE
This is the code that receives the data from the C# NamedPipe Server:
bool CFilePipe::ReadString(int m_handle, string &value)
{
//--- check for data
if(WaitForRead(sizeof(int)))
{
ResetLastError();
int size=FileReadInteger(m_handle);
if(GetLastError()==0)
{
//--- check for data
if(WaitForRead(size))
{
value=FileReadString(m_handle,size);
return(size==StringLen(value));
}
}
}
//--- failure
return(false);
}

Don't take this approach at all. You should be writing to a binary stream of some description - and write the binary data for the length of the packet/message, followed by the message itself. For example:
BinaryWriter writer = new BinaryWriter(stream);
byte[] data = Encoding.UTF8.GetBytes(text);
writer.Write(data.Length);
writer.Write(data);
Then at the other end, you'd use:
BinaryReader reader = new BinaryReader(stream);
int length = reader.ReadInt32();
byte[] data = reader.ReadBytes(length);
string text = Encoding.UTF8.GetString(data);
No need to treat binary data as text at all.

Well. First of all you should get bytes from integer. You can do it with BitConverter:
var bytes = BitConverter.GetBytes(value);
Next, here is three variants. First - if you want to get result in binary format. Just take all your bytes and write as it is:
var str = string.Concat(bytes.Select(b => Convert.ToString(b, 2)));
Second variant. If you want convert your byte array to hexadecimal string:
var hex = BitConverter.ToString(array).Replace("-","");
Third variant. Your representation ("\v\0\0\0") - it is simple converting byte to char. Use this:
var s = bytes.Aggregate(string.Empty, (current, t) => current + Convert.ToChar(t));

This should help with that.
class Program
{
static void Main(string[] args)
{
Random rand = new Random();
int number = rand.Next(1, 1000);
byte[] intBytes = BitConverter.GetBytes(number);
string answer = "";
for (int i = 0; i < intBytes.Length; i++)
{
answer += intBytes[i] + #"\";
}
Console.WriteLine(answer);
Console.WriteLine(number);
Console.ReadKey();
}
}

Obviously, you should implement two steps to achieve the goal:
Extract bytes from the integer in the appropriate order (little-endian or big-endian, it's up to you to decide), using bit arithmetics.
Merge extracted bytes into string using the format you need.
Possible implementation:
using System;
using System.Text;
public class Test
{
public static void Main()
{
Int32 value = 5152;
byte[] bytes = new byte[4];
for (int i = 0; i < 4; i++)
{
bytes[i] = (byte)((value >> i * 8) & 0xFF);
}
StringBuilder result = new StringBuilder();
for (int i = 0; i < 4; i++)
{
result.Append("\\" + bytes[i].ToString("X2"));
}
Console.WriteLine(result);
}
}
Ideone snippet: http://ideone.com/wLloo1

I think you are saying that you want to convert each byte into a character literal, using escape sequences for the non printable characters.
After converting the integer to 4 bytes, cast to char. Then use Char.IsControl() to identify the non-printing characters. Use the printable char directly, and use a lookup table to find the corresponding escape sequence for each non-printable char.

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);

Dotnet Hex string to Java

Have a problem, much like this post: How to read a .NET Guid into a Java UUID.
Except, from a remote svc I get a hex str formatted like this: ABCDEFGH-IJKL-MNOP-QRST-123456.
I need to match the GUID.ToByteArray() generated .net byte array GH-EF-CD-AB-KL-IJ-OP-MN- QR- ST-12-34-56 in Java for hashing purposes.
I'm kinda at a loss as to how to parse this. Do I cut off the QRST-123456 part and perhaps use something like the Commons IO EndianUtils on the other part, then stitch the 2 arrays back together as well? Seems way too complicated.
I can rearrange the string, but I shouldn't have to do any of these. Mr. Google doesn't wanna help me neither..
BTW, what is the logic in Little Endian land that keeps those last 6 char unchanged?
Yes, for reference, here's what I've done {sorry for 'answer', but had trouble formatting it properly in comment}:
String s = "3C0EA2F3-B3A0-8FB0-23F0-9F36DEAA3F7E";
String[] splitz = s.split("-");
String rebuilt = "";
for (int i = 0; i < 3; i++) {
// Split into 2 char chunks. '..' = nbr of chars in chunks
String[] parts = splitz[i].split("(?<=\\G..)");
for (int k = parts.length -1; k >=0; k--) {
rebuilt += parts[k];
}
}
rebuilt += splitz[3]+splitz[4];
I know, it's hacky, but it'll do for testing.

Make it into a byte[] and skip the first 3 bytes:
package guid;
import java.util.Arrays;
public class GuidConvert {
static byte[] convertUuidToBytes(String guid) {
String hexdigits = guid.replaceAll("-", "");
byte[] bytes = new byte[hexdigits.length()/2];
for (int i = 0; i < bytes.length; i++) {
int x = Integer.parseInt(hexdigits.substring(i*2, (i+1)*2), 16);
bytes[i] = (byte) x;
}
return bytes;
}
static String bytesToHexString(byte[] bytes) {
StringBuilder buf = new StringBuilder();
for (byte b : bytes) {
int i = b >= 0 ? b : (int) b + 256;
buf.append(Integer.toHexString(i / 16));
buf.append(Integer.toHexString(i % 16));
}
return buf.toString();
}
public static void main(String[] args) {
String guid = "3C0EA2F3-B3A0-8FB0-23F0-9F36DEAA3F7E";
byte[] bytes = convertUuidToBytes(guid);
System.err.println("GUID = "+ guid);
System.err.println("bytes = "+ bytesToHexString(bytes));
byte[] tail = Arrays.copyOfRange(bytes, 3, bytes.length);
System.err.println("tail = "+ bytesToHexString(tail));
}
}

The last group of 6 bytes is not reversed because it is an array of bytes. The first four groups are reversed because they are a four-byte integer followed by three two-byte integers.