Develop Reference

Convert a hex string to base64

byte[] ba = Encoding.Default.GetBytes(input);
var hexString = BitConverter.ToString(ba);
hexString = hexString.Replace("-", "");
Console.WriteLine("Or: " + hexString + " in hexadecimal");
So I got this, now how would I convert hexString to a base64 string?
I tried this, got the error:
Cannot convert from string to byte[]
If that solution works for anyone else, what am I doing wrong?
edit:
var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);
return System.Convert.ToBase64String(plainTextBytes);
I tried this, but it
returns "Cannot implicitly convert type 'byte[]' to 'string'" on the first
line, then "Argument 1: cannot convert from 'string' to 'byte[]'".

You first need to convert your hexstring to a byte-array, which you can then convert to base-64.
To convert from your hexstring to Base-64, you can use:
public static string HexString2B64String(this string input)
{
return System.Convert.ToBase64String(input.HexStringToHex());
}
Where HexStringToHex is:
public static byte[] HexStringToHex(this string inputHex)
{
var resultantArray = new byte[inputHex.Length / 2];
for (var i = 0; i < resultantArray.Length; i++)
{
resultantArray[i] = System.Convert.ToByte(inputHex.Substring(i * 2, 2), 16);
}
return resultantArray;
}

Since .NET5 it can be done using standard library only:
string HexStringToBase64String(string hexString)
{
// hex-string is converted to byte-array
byte[] stringBytes = System.Convert.FromHexString(hexString);
// byte-array is converted base64-string
string res = System.Convert.ToBase64String(stringBytes);
return res;
}
Also there are good examples in docs

public string HexToBase64(string strInput)
{
try
{
var bytes = new byte[strInput.Length / 2];
for (var i = 0; i < bytes.Length; i++)
{
bytes[i] = Convert.ToByte(strInput.Substring(i * 2, 2), 16);
}
return Convert.ToBase64String(bytes);
}
catch (Exception)
{
return "-1";
}
}
On the contrary: https://stackoverflow.com/a/61224900/3988122

How to read blob data from MySQL in c# [duplicate]

I have a byte[] array that is loaded from a file that I happen to known contains UTF-8.
In some debugging code, I need to convert it to a string. Is there a one-liner that will do this?
Under the covers it should be just an allocation and a memcopy, so even if it is not implemented, it should be possible.

string result = System.Text.Encoding.UTF8.GetString(byteArray);

There're at least four different ways doing this conversion.
Encoding's GetString, but you won't be able to get the original bytes back if those bytes have non-ASCII characters.
BitConverter.ToString The output is a "-" delimited string, but there's no .NET built-in method to convert the string back to byte array.
Convert.ToBase64String You can easily convert the output string back to byte array by using Convert.FromBase64String. Note: The output string could contain '+', '/' and '='. If you want to use the string in a URL, you need to explicitly encode it.
HttpServerUtility.UrlTokenEncodeYou can easily convert the output string back to byte array by using HttpServerUtility.UrlTokenDecode. The output string is already URL friendly! The downside is it needs System.Web assembly if your project is not a web project.
A full example:
byte[] bytes = { 130, 200, 234, 23 }; // A byte array contains non-ASCII (or non-readable) characters
string s1 = Encoding.UTF8.GetString(bytes); // ���
byte[] decBytes1 = Encoding.UTF8.GetBytes(s1); // decBytes1.Length == 10 !!
// decBytes1 not same as bytes
// Using UTF-8 or other Encoding object will get similar results
string s2 = BitConverter.ToString(bytes); // 82-C8-EA-17
String[] tempAry = s2.Split('-');
byte[] decBytes2 = new byte[tempAry.Length];
for (int i = 0; i < tempAry.Length; i++)
decBytes2[i] = Convert.ToByte(tempAry[i], 16);
// decBytes2 same as bytes
string s3 = Convert.ToBase64String(bytes); // gsjqFw==
byte[] decByte3 = Convert.FromBase64String(s3);
// decByte3 same as bytes
string s4 = HttpServerUtility.UrlTokenEncode(bytes); // gsjqFw2
byte[] decBytes4 = HttpServerUtility.UrlTokenDecode(s4);
// decBytes4 same as bytes

A general solution to convert from byte array to string when you don't know the encoding:
static string BytesToStringConverted(byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
{
using (var streamReader = new StreamReader(stream))
{
return streamReader.ReadToEnd();
}
}
}

Definition:
public static string ConvertByteToString(this byte[] source)
{
return source != null ? System.Text.Encoding.UTF8.GetString(source) : null;
}
Using:
string result = input.ConvertByteToString();

Converting a byte[] to a string seems simple, but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:
private string ToString(byte[] bytes)
{
string response = string.Empty;
foreach (byte b in bytes)
response += (Char)b;
return response;
}

I saw some answers at this post and it's possible to be considered completed base knowledge, because I have a several approaches in C# Programming to resolve the same problem. The only thing that is necessary to be considered is about a difference between pure UTF-8 and UTF-8 with a BOM.
Last week, at my job, I needed to develop one functionality that outputs CSV files with a BOM and other CSV files with pure UTF-8 (without a BOM). Each CSV file encoding type will be consumed by different non-standardized APIs. One API reads UTF-8 with a BOM and the other API reads without a BOM. I needed to research the references about this concept, reading the "What's the difference between UTF-8 and UTF-8 without BOM?" Stack Overflow question, and the Wikipedia article "Byte order mark" to build my approach.
Finally, my C# Programming for both UTF-8 encoding types (with BOM and pure) needed to be similar to this example below:
// For UTF-8 with BOM, equals shared by Zanoni (at top)
string result = System.Text.Encoding.UTF8.GetString(byteArray);
//for Pure UTF-8 (without B.O.M.)
string result = (new UTF8Encoding(false)).GetString(byteArray);

Using (byte)b.ToString("x2"), Outputs b4b5dfe475e58b67
public static class Ext {
public static string ToHexString(this byte[] hex)
{
if (hex == null) return null;
if (hex.Length == 0) return string.Empty;
var s = new StringBuilder();
foreach (byte b in hex) {
s.Append(b.ToString("x2"));
}
return s.ToString();
}
public static byte[] ToHexBytes(this string hex)
{
if (hex == null) return null;
if (hex.Length == 0) return new byte[0];
int l = hex.Length / 2;
var b = new byte[l];
for (int i = 0; i < l; ++i) {
b[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
return b;
}
public static bool EqualsTo(this byte[] bytes, byte[] bytesToCompare)
{
if (bytes == null && bytesToCompare == null) return true; // ?
if (bytes == null || bytesToCompare == null) return false;
if (object.ReferenceEquals(bytes, bytesToCompare)) return true;
if (bytes.Length != bytesToCompare.Length) return false;
for (int i = 0; i < bytes.Length; ++i) {
if (bytes[i] != bytesToCompare[i]) return false;
}
return true;
}
}

There is also class UnicodeEncoding, quite simple in usage:
ByteConverter = new UnicodeEncoding();
string stringDataForEncoding = "My Secret Data!";
byte[] dataEncoded = ByteConverter.GetBytes(stringDataForEncoding);
Console.WriteLine("Data after decoding: {0}", ByteConverter.GetString(dataEncoded));

In addition to the selected answer, if you're using .NET 3.5 or .NET 3.5 CE, you have to specify the index of the first byte to decode, and the number of bytes to decode:
string result = System.Text.Encoding.UTF8.GetString(byteArray, 0, byteArray.Length);

Alternatively:
var byteStr = Convert.ToBase64String(bytes);

The BitConverter class can be used to convert a byte[] to string.
var convertedString = BitConverter.ToString(byteAttay);
Documentation of BitConverter class can be fount on MSDN.

To my knowledge none of the given answers guarantee correct behavior with null termination. Until someone shows me differently I wrote my own static class for handling this with the following methods:
// Mimics the functionality of strlen() in c/c++
// Needed because niether StringBuilder or Encoding.*.GetString() handle \0 well
static int StringLength(byte[] buffer, int startIndex = 0)
{
int strlen = 0;
while
(
(startIndex + strlen + 1) < buffer.Length // Make sure incrementing won't break any bounds
&& buffer[startIndex + strlen] != 0 // The typical null terimation check
)
{
++strlen;
}
return strlen;
}
// This is messy, but I haven't found a built-in way in c# that guarentees null termination
public static string ParseBytes(byte[] buffer, out int strlen, int startIndex = 0)
{
strlen = StringLength(buffer, startIndex);
byte[] c_str = new byte[strlen];
Array.Copy(buffer, startIndex, c_str, 0, strlen);
return Encoding.UTF8.GetString(c_str);
}
The reason for the startIndex was in the example I was working on specifically I needed to parse a byte[] as an array of null terminated strings. It can be safely ignored in the simple case

A LINQ one-liner for converting a byte array byteArrFilename read from a file to a pure ASCII C-style zero-terminated string would be this: Handy for reading things like file index tables in old archive formats.
String filename = new String(byteArrFilename.TakeWhile(x => x != 0)
.Select(x => x < 128 ? (Char)x : '?').ToArray());
I use '?' as the default character for anything not pure ASCII here, but that can be changed, of course. If you want to be sure you can detect it, just use '\0' instead, since the TakeWhile at the start ensures that a string built this way cannot possibly contain '\0' values from the input source.

Try this console application:
static void Main(string[] args)
{
//Encoding _UTF8 = Encoding.UTF8;
string[] _mainString = { "Hello, World!" };
Console.WriteLine("Main String: " + _mainString);
// Convert a string to UTF-8 bytes.
byte[] _utf8Bytes = Encoding.UTF8.GetBytes(_mainString[0]);
// Convert UTF-8 bytes to a string.
string _stringuUnicode = Encoding.UTF8.GetString(_utf8Bytes);
Console.WriteLine("String Unicode: " + _stringuUnicode);
}

Here is a result where you didn’t have to bother with encoding. I used it in my network class and send binary objects as string with it.
public static byte[] String2ByteArray(string str)
{
char[] chars = str.ToArray();
byte[] bytes = new byte[chars.Length * 2];
for (int i = 0; i < chars.Length; i++)
Array.Copy(BitConverter.GetBytes(chars[i]), 0, bytes, i * 2, 2);
return bytes;
}
public static string ByteArray2String(byte[] bytes)
{
char[] chars = new char[bytes.Length / 2];
for (int i = 0; i < chars.Length; i++)
chars[i] = BitConverter.ToChar(bytes, i * 2);
return new string(chars);
}

string result = ASCIIEncoding.UTF8.GetString(byteArray);

Binary To Corresponding ASCII String Conversion

Hi i was able to convert a ASCII string to binary using a binarywriter .. as 10101011 . im required back to convert Binary ---> ASCII string .. any idea how to do it ?

This should do the trick... or at least get you started...
public 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();
}
Once the binary string has been converted to a byte array, finish off with
Encoding.ASCII.GetString(data);
So...
var data = GetBytesFromBinaryString("010000010100001001000011");
var text = Encoding.ASCII.GetString(data);

If you have ASCII charters only you could use Encoding.ASCII.GetBytes and Encoding.ASCII.GetString.
var text = "Test";
var bytes = Encoding.ASCII.GetBytes(text);
var newText = Encoding.ASCII.GetString(bytes);

Here is complete code for your answer
FileStream iFile = new FileStream(#"c:\test\binary.dat",
FileMode.Open);
long lengthInBytes = iFile.Length;
BinaryReader bin = new BinaryReader(aFile);
byte[] byteArray = bin.ReadBytes((int)lengthInBytes);
System.Text.Encoding encEncoder = System.Text.ASCIIEncoding.ASCII;
string str = encEncoder.GetString(byteArray);

Take this as a simple example:
public void ByteToString()
{
Byte[] arrByte = { 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0 };
string x = Convert.ToBase64String(arrByte);
}
This linked answer has interesting details about this kind of conversion:
binary file to string

Sometimes instead of using the built in tools it's better to use "custom" code.. try this function:
public string BinaryToString(string binary)
{
if (string.IsNullOrEmpty(binary))
throw new ArgumentNullException("binary");
if ((binary.Length % 8) != 0)
throw new ArgumentException("Binary string invalid (must divide by 8)", "binary");
StringBuilder builder = new StringBuilder();
for (int i = 0; i < binary.Length; i += 8)
{
string section = binary.Substring(i, 8);
int ascii = 0;
try
{
ascii = Convert.ToInt32(section, 2);
}
catch
{
throw new ArgumentException("Binary string contains invalid section: " + section, "binary");
}
builder.Append((char)ascii);
}
return builder.ToString();
}
Tested with 010000010100001001000011 it returned ABC using the "raw" ASCII values.

How to convert UTF-8 byte[] to string

I have a byte[] array that is loaded from a file that I happen to known contains UTF-8.
In some debugging code, I need to convert it to a string. Is there a one-liner that will do this?
Under the covers it should be just an allocation and a memcopy, so even if it is not implemented, it should be possible.

string result = System.Text.Encoding.UTF8.GetString(byteArray);

There're at least four different ways doing this conversion.
Encoding's GetString, but you won't be able to get the original bytes back if those bytes have non-ASCII characters.
BitConverter.ToString The output is a "-" delimited string, but there's no .NET built-in method to convert the string back to byte array.
Convert.ToBase64String You can easily convert the output string back to byte array by using Convert.FromBase64String. Note: The output string could contain '+', '/' and '='. If you want to use the string in a URL, you need to explicitly encode it.
HttpServerUtility.UrlTokenEncodeYou can easily convert the output string back to byte array by using HttpServerUtility.UrlTokenDecode. The output string is already URL friendly! The downside is it needs System.Web assembly if your project is not a web project.
A full example:
byte[] bytes = { 130, 200, 234, 23 }; // A byte array contains non-ASCII (or non-readable) characters
string s1 = Encoding.UTF8.GetString(bytes); // ���
byte[] decBytes1 = Encoding.UTF8.GetBytes(s1); // decBytes1.Length == 10 !!
// decBytes1 not same as bytes
// Using UTF-8 or other Encoding object will get similar results
string s2 = BitConverter.ToString(bytes); // 82-C8-EA-17
String[] tempAry = s2.Split('-');
byte[] decBytes2 = new byte[tempAry.Length];
for (int i = 0; i < tempAry.Length; i++)
decBytes2[i] = Convert.ToByte(tempAry[i], 16);
// decBytes2 same as bytes
string s3 = Convert.ToBase64String(bytes); // gsjqFw==
byte[] decByte3 = Convert.FromBase64String(s3);
// decByte3 same as bytes
string s4 = HttpServerUtility.UrlTokenEncode(bytes); // gsjqFw2
byte[] decBytes4 = HttpServerUtility.UrlTokenDecode(s4);
// decBytes4 same as bytes

A general solution to convert from byte array to string when you don't know the encoding:
static string BytesToStringConverted(byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
{
using (var streamReader = new StreamReader(stream))
{
return streamReader.ReadToEnd();
}
}
}

Definition:
public static string ConvertByteToString(this byte[] source)
{
return source != null ? System.Text.Encoding.UTF8.GetString(source) : null;
}
Using:
string result = input.ConvertByteToString();

Converting a byte[] to a string seems simple, but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:
private string ToString(byte[] bytes)
{
string response = string.Empty;
foreach (byte b in bytes)
response += (Char)b;
return response;
}

I saw some answers at this post and it's possible to be considered completed base knowledge, because I have a several approaches in C# Programming to resolve the same problem. The only thing that is necessary to be considered is about a difference between pure UTF-8 and UTF-8 with a BOM.
Last week, at my job, I needed to develop one functionality that outputs CSV files with a BOM and other CSV files with pure UTF-8 (without a BOM). Each CSV file encoding type will be consumed by different non-standardized APIs. One API reads UTF-8 with a BOM and the other API reads without a BOM. I needed to research the references about this concept, reading the "What's the difference between UTF-8 and UTF-8 without BOM?" Stack Overflow question, and the Wikipedia article "Byte order mark" to build my approach.
Finally, my C# Programming for both UTF-8 encoding types (with BOM and pure) needed to be similar to this example below:
// For UTF-8 with BOM, equals shared by Zanoni (at top)
string result = System.Text.Encoding.UTF8.GetString(byteArray);
//for Pure UTF-8 (without B.O.M.)
string result = (new UTF8Encoding(false)).GetString(byteArray);

Using (byte)b.ToString("x2"), Outputs b4b5dfe475e58b67
public static class Ext {
public static string ToHexString(this byte[] hex)
{
if (hex == null) return null;
if (hex.Length == 0) return string.Empty;
var s = new StringBuilder();
foreach (byte b in hex) {
s.Append(b.ToString("x2"));
}
return s.ToString();
}
public static byte[] ToHexBytes(this string hex)
{
if (hex == null) return null;
if (hex.Length == 0) return new byte[0];
int l = hex.Length / 2;
var b = new byte[l];
for (int i = 0; i < l; ++i) {
b[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
return b;
}
public static bool EqualsTo(this byte[] bytes, byte[] bytesToCompare)
{
if (bytes == null && bytesToCompare == null) return true; // ?
if (bytes == null || bytesToCompare == null) return false;
if (object.ReferenceEquals(bytes, bytesToCompare)) return true;
if (bytes.Length != bytesToCompare.Length) return false;
for (int i = 0; i < bytes.Length; ++i) {
if (bytes[i] != bytesToCompare[i]) return false;
}
return true;
}
}

There is also class UnicodeEncoding, quite simple in usage:
ByteConverter = new UnicodeEncoding();
string stringDataForEncoding = "My Secret Data!";
byte[] dataEncoded = ByteConverter.GetBytes(stringDataForEncoding);
Console.WriteLine("Data after decoding: {0}", ByteConverter.GetString(dataEncoded));

In addition to the selected answer, if you're using .NET 3.5 or .NET 3.5 CE, you have to specify the index of the first byte to decode, and the number of bytes to decode:
string result = System.Text.Encoding.UTF8.GetString(byteArray, 0, byteArray.Length);

Alternatively:
var byteStr = Convert.ToBase64String(bytes);

The BitConverter class can be used to convert a byte[] to string.
var convertedString = BitConverter.ToString(byteAttay);
Documentation of BitConverter class can be fount on MSDN.

To my knowledge none of the given answers guarantee correct behavior with null termination. Until someone shows me differently I wrote my own static class for handling this with the following methods:
// Mimics the functionality of strlen() in c/c++
// Needed because niether StringBuilder or Encoding.*.GetString() handle \0 well
static int StringLength(byte[] buffer, int startIndex = 0)
{
int strlen = 0;
while
(
(startIndex + strlen + 1) < buffer.Length // Make sure incrementing won't break any bounds
&& buffer[startIndex + strlen] != 0 // The typical null terimation check
)
{
++strlen;
}
return strlen;
}
// This is messy, but I haven't found a built-in way in c# that guarentees null termination
public static string ParseBytes(byte[] buffer, out int strlen, int startIndex = 0)
{
strlen = StringLength(buffer, startIndex);
byte[] c_str = new byte[strlen];
Array.Copy(buffer, startIndex, c_str, 0, strlen);
return Encoding.UTF8.GetString(c_str);
}
The reason for the startIndex was in the example I was working on specifically I needed to parse a byte[] as an array of null terminated strings. It can be safely ignored in the simple case

A LINQ one-liner for converting a byte array byteArrFilename read from a file to a pure ASCII C-style zero-terminated string would be this: Handy for reading things like file index tables in old archive formats.
String filename = new String(byteArrFilename.TakeWhile(x => x != 0)
.Select(x => x < 128 ? (Char)x : '?').ToArray());
I use '?' as the default character for anything not pure ASCII here, but that can be changed, of course. If you want to be sure you can detect it, just use '\0' instead, since the TakeWhile at the start ensures that a string built this way cannot possibly contain '\0' values from the input source.

Try this console application:
static void Main(string[] args)
{
//Encoding _UTF8 = Encoding.UTF8;
string[] _mainString = { "Hello, World!" };
Console.WriteLine("Main String: " + _mainString);
// Convert a string to UTF-8 bytes.
byte[] _utf8Bytes = Encoding.UTF8.GetBytes(_mainString[0]);
// Convert UTF-8 bytes to a string.
string _stringuUnicode = Encoding.UTF8.GetString(_utf8Bytes);
Console.WriteLine("String Unicode: " + _stringuUnicode);
}

Here is a result where you didn’t have to bother with encoding. I used it in my network class and send binary objects as string with it.
public static byte[] String2ByteArray(string str)
{
char[] chars = str.ToArray();
byte[] bytes = new byte[chars.Length * 2];
for (int i = 0; i < chars.Length; i++)
Array.Copy(BitConverter.GetBytes(chars[i]), 0, bytes, i * 2, 2);
return bytes;
}
public static string ByteArray2String(byte[] bytes)
{
char[] chars = new char[bytes.Length / 2];
for (int i = 0; i < chars.Length; i++)
chars[i] = BitConverter.ToChar(bytes, i * 2);
return new string(chars);
}

string result = ASCIIEncoding.UTF8.GetString(byteArray);

Convert PHP encryption code to C#

I'm trying to convert this piece of code from PHP to C#. It's part of a Captive Portal. Could somebody explain what it does?
$hexchal = pack ("H32", $challenge);
if ($uamsecret) {
$newchal = pack ("H*", md5($hexchal . $uamsecret));
} else {
$newchal = $hexchal;
}
$response = md5("\0" . $password . $newchal);
$newpwd = pack("a32", $password);
$pappassword = implode ("", unpack("H32", ($newpwd ^ $newchal)));

I also encountered the need of php's pack-unpack functions in c# but did not get any good resource.
So i thought to do it myself. I have verified the function's input with pack/unpack/md5 methods found at onlinephpfunctions.com. Since i have done code only as per my requirements. This can be extended for other formats
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();
}

Eduardo,
if you take a look at the pack manual, pack is used to convert a string in (hex, octal, binary )to his number representation.
so
$hexcal = pack('H32', $challenge);
would convert a string like 'cca86bc64ec5889345c4c3d8dfc7ade9' to the actual 0xcca... de9
if $uamsecret exist do the same things with the MD5 of hexchal concacteate with the uamsecret.
if ($uamsecret) {
$newchal = pack ("H*", md5($hexchal . $uamsecret));
} else {
$newchal = $hexchal;
}
$response = md5("\0" . $password . $newchal);
MD% '\0' + $password + $newchal
$newpwd = pack("a32", $password);
pad password to 32 byte
$pappassword = implode ("", unpack("H32", ($newpwd ^ $newchal)));
do a xor newpwd and newchal and convert it to a hexadecimal string, I don't get the implode() maybe it's to convert to string to an array of character.