Develop Reference

Converting String to Hex then into Byte Array

So,
I have a string that I want to convert each character to hex values and then put it in a byte array to be sent through a com port.
I can convert the individual characters to the hex that I need to send, but I can't get that array of strings into a byte array correctly.
example:
string beforeConverting = "HELLO";
String[] afterConverting = {"0x48", "0x45", "0x4C", "0x4C", "0x4F"};
should become
byte[] byteData = new byte[]{0x48, 0x45, 0x4C, 0x4C, 0x4F};
I've tried several different things from several different posts but I can't get the right combination of things together. If anyone could point me in the right direction or give me a snippet of example code that would be awesome!

If your final aim is to send byte[], then you can actually skip the middle step and immediately do the conversion from string to byte[] using Encoding.ASCII.GetBytes (provided that you send ASCII char):
string beforeConverting = "HELLO";
byte[] byteData = Encoding.ASCII.GetBytes(beforeConverting);
//will give you {0x48, 0x45, 0x4C, 0x4C, 0x4F};
If you don't send ASCII, you could find the appropriate Encoding type (like Unicode or UTF32), depends on your need.
That being said, if you still want to convert the hex string to byte array, you could do something something like this:
/// <summary>
/// To convert Hex data string to bytes (i.e. 0x01455687) given the data type
/// </summary>
/// <param name="hexString"></param>
/// <param name="dataType"></param>
/// <returns></returns>
public static byte[] HexStringToBytes(string hexString) {
try {
if (hexString.Length >= 3) //must have minimum of length of 3
if (hexString[0] == '0' && (hexString[1] == 'x' || hexString[1] == 'X'))
hexString = hexString.Substring(2);
int dataSize = (hexString.Length - 1) / 2;
int expectedStringLength = 2 * dataSize;
while (hexString.Length < expectedStringLength)
hexString = "0" + hexString; //zero padding in the front
int NumberChars = hexString.Length / 2;
byte[] bytes = new byte[NumberChars];
using (var sr = new StringReader(hexString)) {
for (int i = 0; i < NumberChars; i++)
bytes[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);
}
return bytes;
} catch {
return null;
}
}
And then use it like this:
byte[] byteData = afterConverting.Select(x => HexStringToBytes(x)[0]).ToArray();
The method I put above is more general which can handle input string like 0x05163782 to give byte[4]. For your use, you only need to take the first byte (as the byte[] will always be byte[1]) and thus you have [0] index in the LINQ Select.
The core method used in the custom method above is Convert.ToByte():
bytes[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);

To convert just the hexadecimal string to a number, you could use the System.Convert class like so
string hex = "0x3B";
byte b = Convert.ToByte(hex.Substring(2), 16)
// b is now 0x3B
Substring is used to skip the characters 0x

Convert Unicode string into proper string

I have a string which contains unicode data.
I want to write it in a file . When the data is written in file it gives me simple unicode value instead of languages other than english.
string originalString = ((char)(buffer[index])).ToString();
//sb.Append(DecodeEncodedNonAsciiCharacters(originalString.ToString()));
foreach (char c1 in originalString)
{
// test if char is ascii, otherwise convert to Unicode Code Point
int cint = Convert.ToInt32(c1);
if (cint <= 127 && cint >= 0)
asAscii.Append(c1.ToString());
else
{
//String s = Char.ConvertFromUtf32(cint);
asAscii.Append(String.Format("\\u{0:x4} ", cint).Trim());
// asAscii.Append(s);
}
}
sb.Append((asAscii));
Console.WriteLine();
when i see the output file the data shows like this
1 00:00:27,709-->00:00:32,959
1.2 \u00e0\u00a4\u0085\u00e0\u00a4\u00b0\u00e0\u00a4\u00ac \u00e0\u00a4\u00b2\u00e0\u00a5\u008b\u00e0\u00a4\u0097 28
\u00e0\u00a4\u00b0\u00e0\u00a4\u00be\u00e0\u00a4\u009c\u00e0\u00a5\u008d\u00e0\u00a4\u00af
\u00e0\u00a4\u0094\u00e0\u00a4\u00b0
\u00e0\u00a4\u00b8\u00e0\u00a4\u00be\u00e0\u00a4\u00a4
\u00e0\u00a4\u0095\u00e0\u00a5\u0087\u00e0\u00a4\u0082\u00e0\u00a4\u00a6\u00e0\u00a5\u008d\u00e0\u00a4\u00b0
\u00e0\u00a4\u00b6\u00e0\u00a4\u00be\u00e0\u00a4\u00b8\u00e0\u00a4\u00bf\u00e0\u00a4\u00a4
\u00e0\u00a4\u00aa\u00e0\u00a5\u008d\u00e0\u00a4\u00b0\u00e0\u00a4\u00a6\u00e0\u00a5\u0087\u00e0\u00a4\u00b6
but it should look like this
1 00:00:27,400 --> 00:00:32,760
1.2 अरब लोग 28 राज्य और सात केंद्र शासित प्रदेश
I have tried many things but none has done my job.

string unicodeString = "This string contains the unicode character Pi(\u03a0)";
// Create two different encodings.
Encoding ascii = Encoding.ASCII;
Encoding unicode = Encoding.Unicode;
// Convert the string into a byte[].
byte[] unicodeBytes = unicode.GetBytes(unicodeString);
// Perform the conversion from one encoding to the other.
byte[] asciiBytes = Encoding.Convert(unicode, ascii, unicodeBytes);
// Convert the new byte[] into a char[] and then into a string.
// This is a slightly different approach to converting to illustrate
// the use of GetCharCount/GetChars.
char[] asciiChars = new char[ascii.GetCharCount(asciiBytes, 0, asciiBytes.Length)];
ascii.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0);
string asciiString = new string(asciiChars);
// Display the strings created before and after the conversion.
Console.WriteLine("Original string: {0}", unicodeString);
Console.WriteLine("Ascii converted string: {0}", asciiString);

Are there any rules for the XOR cipher?

I have the following method which takes the plain text and the key text. It is supposed to return a string encrypted with the XOR method as ascii.
public static string encryptXOREng(string plainText,string keyText)
{
StringBuilder chiffreText = new StringBuilder();
byte[] binaryPlainText = System.Text.Encoding.ASCII.GetBytes(plainText);
byte[] binaryKeyText = System.Text.Encoding.ASCII.GetBytes(keyText);
for(int i = 0;i<plainText.Length;i++)
{
int result = binaryPlainText[i] ^ binaryKeyText[i];
chiffreText.Append(Convert.ToChar(result));
}
return chiffreText.ToString();
}
For some characters it runs just fine. But for example if it performs XOR on 'G' & 'M', which is 71 XOR 77 it returns 10. And 10 stands for Line feed. This is then actually not represented by a character in my output. This leads to a plain text of a length being encrypted to a cipher string which is only 2 characters long, in some cases. I suppose this would make a decryption impossible, even with a key? Or are the ascii characters 0 - 31 there but simply not visible?

To avoid non printable chars use Convert.ToBase64String
public static string encryptXOREng(string plainText, string keyText)
{
List<byte> chiffreText = new List<byte>();
byte[] binaryPlainText = System.Text.Encoding.ASCII.GetBytes(plainText);
byte[] binaryKeyText = System.Text.Encoding.ASCII.GetBytes(keyText);
for (int i = 0; i < plainText.Length; i++)
{
int result = binaryPlainText[i] ^ binaryKeyText[i % binaryKeyText.Length];
chiffreText.Add((byte)result);
}
return Convert.ToBase64String(chiffreText.ToArray());
}
PS: In your code you assume keyText is not shorter than plainText, I fixed it also.

As far as i know there are no rules specific to xor-ciphers. Cryptographic functions often output values that are not printable, which makes sense - the result is not supposed to be readable. In stead you may want to use the output bytes directly or a base64 encoded result.
I would do something like:
public static byte[] XORCipher(string plainText, string keyText)
{
byte[] binaryPlainText = System.Text.Encoding.ASCII.GetBytes(plainText);
byte[] binaryKeyText = System.Text.Encoding.ASCII.GetBytes(keyText);
for(int i = 0;i<plainText.Length;i++)
{
binaryPlainText[i] ^= binaryKeyText[i];
}
return binaryPlainText;
}

How to convert a string to byte array

I have a string and want to convert it to a byte array of hex value using C#.
for eg, "Hello World!" to byte[] val=new byte[] {0x48, 0x65, 0x6C, 0x6C, 0x6F, 0x20, 0x57, 0x6F, 0x72, 0x6C, 0x64, 0x21};,
I see the following code in Converting string value to hex decimal
string input = "Hello World!";
char[] values = input.ToCharArray();
foreach (char letter in values)
{
// Get the integral value of the character.
int value = Convert.ToInt32(letter);
// Convert the decimal value to a hexadecimal value in string form.
string hexOutput = String.Format("0x{0:X}", value);
Console.WriteLine("Hexadecimal value of {0} is {1}", letter, hexOutput);
}
I want this value into byte array but can't write like this
byte[] yy = new byte[values.Length];
yy[i] = Convert.ToByte(Convert.ToInt32(hexOutput));
I try this code referenced from How to convert a String to a Hex Byte Array? where I passed the hex value 48656C6C6F20576F726C6421 but I got the decimal value not hex.
public byte[] ToByteArray(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;
}
and I also try code from How can I convert a hex string to a byte array?
But once I used Convert.ToByte or byte.Parse , the value change to decimal value.
How should I do?
Thanks in advance
I want to send 0x80 (i.e, 128) to serial port but when I copy and paste the character equivalent to 128 to the variable 'input' and convert to byte, I got 63 (0x3F). So I think I need to send hex array. I think I got the wrong idea. Pls see screen shot.
For now, I solve this to combine byte arrays.
string input = "Hello World!";
byte[] header = new byte[] { 2, 48, 128 };
byte[] body = Encoding.ASCII.GetBytes(input);

Hexadecimal has nothing to do with this, your desired result is nothing more nor less than an array of bytes containing the ASCII codes.
Try Encoding.ASCII.GetBytes(s)

There's something strange with your requirement:
I have a string and want to convert it to a byte array of hex value
using C#.
An byte is just an 8-bit value. You can present it as decimal (e.g. 16) or hexidecimal (e.g. 0x10).
So, what do you realy want?

In case you are really wanting to get a string which contains the hex representation of an array of bytes, here's how you can do that:
public static string BytesAsString(byte[] bytes)
{
string hex = BitConverter.ToString(bytes); // This puts "-" between each value.
return hex.Replace("-",""); // So we remove "-" here.
}

It seems like you’re mixing converting to array and displaying array data.
When you have array of bytes it’s just array of bytes and you can represent it in any possible way binary, decimal, hexadecimal, octal, whatever… but that is only valid if you want to visually represent these.
Here is a code that manually converts string to byte array and then to array of strings in hex format.
string s1 = "Stack Overflow :)";
byte[] bytes = new byte[s1.Length];
for (int i = 0; i < s1.Length; i++)
{
bytes[i] = Convert.ToByte(s1[i]);
}
List<string> hexStrings = new List<string>();
foreach (byte b in bytes)
{
hexStrings.Add(Convert.ToInt32(b).ToString("X"));
}

HEX String to Chinese String

I have the following code to convert from HEX to ASCII.
//Hexadecimal to ASCII Convertion
private static string hex2ascii(string hexString)
{
MessageBox.Show(hexString);
StringBuilder sb = new StringBuilder();
for (int i = 0; i <= hexString.Length - 2; i += 2)
{
sb.Append(Convert.ToString(Convert.ToChar(Int32.Parse(hexString.Substring(i, 2), System.Globalization.NumberStyles.HexNumber))));
}
return sb.ToString();
}
input hexString = D3FCC4A7B6FABBB7
output return = Óüħ¶ú»·
The output that I need is 狱魔耳环, but I am getting Óüħ¶ú»· instead.
How would I make it display the correct string?

First, convert the hex string to a byte[], e.g. using code at How do you convert Byte Array to Hexadecimal String, and vice versa?. Then use System.Text.Encoding.Unicode.GetString(myArray) (use proper encoding, might not be Unicode, but judging from your example it is a 16-bit encoding, which, incidentally, is not "ASCII", which is 7-bit) to convert it to a string.