I use the following C# code to calculate a MD5 hash from a string.
It works well and generates a 32-character hex string like this:
900150983cd24fb0d6963f7d28e17f72
string sSourceData;
byte[] tmpSource;
byte[] tmpHash;
sSourceData = "MySourceData";
//Create a byte array from source data.
tmpSource = ASCIIEncoding.ASCII.GetBytes(sSourceData);
tmpHash = new MD5CryptoServiceProvider().ComputeHash(tmpSource);
// and then convert tmpHash to string...
Is there a way to use code like this to generate a 16-character hex string (or 12-character string)? A 32-character hex string is good but I think it'll be boring for the customer to enter the code!
As per MSDN
Create MD5:
public static string CreateMD5(string input)
{
// Use input string to calculate MD5 hash
using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
{
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
byte[] hashBytes = md5.ComputeHash(inputBytes);
return Convert.ToHexString(hashBytes); // .NET 5 +
// Convert the byte array to hexadecimal string prior to .NET 5
// StringBuilder sb = new System.Text.StringBuilder();
// for (int i = 0; i < hashBytes.Length; i++)
// {
// sb.Append(hashBytes[i].ToString("X2"));
// }
// return sb.ToString();
}
}
// given, a password in a string
string password = #"1234abcd";
// byte array representation of that string
byte[] encodedPassword = new UTF8Encoding().GetBytes(password);
// need MD5 to calculate the hash
byte[] hash = ((HashAlgorithm) CryptoConfig.CreateFromName("MD5")).ComputeHash(encodedPassword);
// string representation (similar to UNIX format)
string encoded = BitConverter.ToString(hash)
// without dashes
.Replace("-", string.Empty)
// make lowercase
.ToLower();
// encoded contains the hash you want
Was trying to create a string representation of MD5 hash using LINQ, however, none of the answers were LINQ solutions, therefore adding this to the smorgasbord of available solutions.
string result;
using (MD5 hash = MD5.Create())
{
result = String.Join
(
"",
from ba in hash.ComputeHash
(
Encoding.UTF8.GetBytes(observedText)
)
select ba.ToString("x2")
);
}
You can use Convert.ToBase64String to convert 16 byte output of MD5 to a ~24 char string. A little bit better without reducing security. (j9JIbSY8HuT89/pwdC8jlw== for your example)
Depends entirely on what you are trying to achieve. Technically, you could just take the first 12 characters from the result of the MD5 hash, but the specification of MD5 is to generate a 32 char one.
Reducing the size of the hash reduces the security, and increases the chance of collisions and the system being broken.
Perhaps if you let us know more about what you are trying to achieve we may be able to assist more.
I suppose it is better to use UTF-8 encoding in the string MD5.
public static string MD5(this string s)
{
using var provider = System.Security.Cryptography.MD5.Create();
StringBuilder builder = new StringBuilder();
foreach (byte b in provider.ComputeHash(Encoding.UTF8.GetBytes(s)))
builder.Append(b.ToString("x2").ToLower());
return builder.ToString();
}
public static string Md5(string input, bool isLowercase = false)
{
using (var md5 = MD5.Create())
{
var byteHash = md5.ComputeHash(Encoding.UTF8.GetBytes(input));
var hash = BitConverter.ToString(byteHash).Replace("-", "");
return (isLowercase) ? hash.ToLower() : hash;
}
}
Support string and file stream.
examples
string hashString = EasyMD5.Hash("My String");
string hashFile = EasyMD5.Hash(System.IO.File.OpenRead("myFile.txt"));
-
class EasyMD5
{
private static string GetMd5Hash(byte[] data)
{
StringBuilder sBuilder = new StringBuilder();
for (int i = 0; i < data.Length; i++)
sBuilder.Append(data[i].ToString("x2"));
return sBuilder.ToString();
}
private static bool VerifyMd5Hash(byte[] data, string hash)
{
return 0 == StringComparer.OrdinalIgnoreCase.Compare(GetMd5Hash(data), hash);
}
public static string Hash(string data)
{
using (var md5 = MD5.Create())
return GetMd5Hash(md5.ComputeHash(Encoding.UTF8.GetBytes(data)));
}
public static string Hash(FileStream data)
{
using (var md5 = MD5.Create())
return GetMd5Hash(md5.ComputeHash(data));
}
public static bool Verify(string data, string hash)
{
using (var md5 = MD5.Create())
return VerifyMd5Hash(md5.ComputeHash(Encoding.UTF8.GetBytes(data)), hash);
}
public static bool Verify(FileStream data, string hash)
{
using (var md5 = MD5.Create())
return VerifyMd5Hash(md5.ComputeHash(data), hash);
}
}
Idk anything about 16 character hex strings....
using System;
using System.Security.Cryptography;
using System.Text;
But here is mine for creating MD5 hash in one line.
string hash = BitConverter.ToString(MD5.Create().ComputeHash(Encoding.ASCII.GetBytes("THIS STRING TO MD5"))).Replace("-","");
This solution requires c# 8 and takes advantage of Span<T>. Note, you would still need to call .Replace("-", string.Empty).ToLowerInvariant() to format the result if necessary.
public static string CreateMD5(ReadOnlySpan<char> input)
{
var encoding = System.Text.Encoding.UTF8;
var inputByteCount = encoding.GetByteCount(input);
using var md5 = System.Security.Cryptography.MD5.Create();
Span<byte> bytes = inputByteCount < 1024
? stackalloc byte[inputByteCount]
: new byte[inputByteCount];
Span<byte> destination = stackalloc byte[md5.HashSize / 8];
encoding.GetBytes(input, bytes);
// checking the result is not required because this only returns false if "(destination.Length < HashSizeValue/8)", which is never true in this case
md5.TryComputeHash(bytes, destination, out int _bytesWritten);
return BitConverter.ToString(destination.ToArray());
}
Here is my utility function for UTF8, which can be replaced with ASCII if desired:
public static byte[] MD5Hash(string message)
{
return MD5.Create().ComputeHash(Encoding.UTF8.GetBytes(message));
}
A MD5 hash is 128 bits, so you can't represent it in hex with less than 32 characters...
System.Text.StringBuilder hash = new System.Text.StringBuilder();
System.Security.Cryptography.MD5CryptoServiceProvider md5provider = new System.Security.Cryptography.MD5CryptoServiceProvider();
byte[] bytes = md5provider.ComputeHash(new System.Text.UTF8Encoding().GetBytes(YourEntryString));
for (int i = 0; i < bytes.Length; i++)
{
hash.Append(bytes[i].ToString("x2")); //lowerCase; X2 if uppercase desired
}
return hash.ToString();
A faster alternative of existing answer for .NET Core 2.1 and higher:
public static string CreateMD5(string s)
{
using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
{
var encoding = Encoding.ASCII;
var data = encoding.GetBytes(s);
Span<byte> hashBytes = stackalloc byte[16];
md5.TryComputeHash(data, hashBytes, out int written);
if(written != hashBytes.Length)
throw new OverflowException();
Span<char> stringBuffer = stackalloc char[32];
for (int i = 0; i < hashBytes.Length; i++)
{
hashBytes[i].TryFormat(stringBuffer.Slice(2 * i), out _, "x2");
}
return new string(stringBuffer);
}
}
You can optimize it even more if you are sure that your strings are small enough and replace encoding.GetBytes by unsafe int GetBytes(ReadOnlySpan chars, Span bytes) alternative.
Extending Anant Dabhi's answer
a helper method:
using System.Text;
namespace XYZ.Helpers
{
public static class EncryptionHelper
{
public static string ToMD5(this string input)
{
// Use input string to calculate MD5 hash
using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
{
byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
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"));
}
return sb.ToString();
}
}
}
}
I'd like to offer an alternative that appears to perform at least 10% faster than craigdfrench's answer in my tests (.NET 4.7.2):
public static string GetMD5Hash(string text)
{
using ( var md5 = MD5.Create() )
{
byte[] computedHash = md5.ComputeHash( Encoding.UTF8.GetBytes(text) );
return new System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary(computedHash).ToString();
}
}
If you prefer to have using System.Runtime.Remoting.Metadata.W3cXsd2001; at the top, the method body can be made an easier to read one-liner:
using ( var md5 = MD5.Create() )
{
return new SoapHexBinary( md5.ComputeHash( Encoding.UTF8.GetBytes(text) ) ).ToString();
}
Obvious enough, but for completeness, in OP's context it would be used as:
sSourceData = "MySourceData";
tmpHash = GetMD5Hash(sSourceData);
https://learn.microsoft.com/en-us/dotnet/api/system.security.cryptography.md5?view=netframework-4.7.2
using System;
using System.Security.Cryptography;
using System.Text;
static string GetMd5Hash(string input)
{
using (MD5 md5Hash = MD5.Create())
{
// Convert the input string to a byte array and compute the hash.
byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));
// Create a new Stringbuilder to collect the bytes
// and create a string.
StringBuilder sBuilder = new StringBuilder();
// Loop through each byte of the hashed data
// and format each one as a hexadecimal string.
for (int i = 0; i < data.Length; i++)
{
sBuilder.Append(data[i].ToString("x2"));
}
// Return the hexadecimal string.
return sBuilder.ToString();
}
}
// Verify a hash against a string.
static bool VerifyMd5Hash(string input, string hash)
{
// Hash the input.
string hashOfInput = GetMd5Hash(input);
// Create a StringComparer an compare the hashes.
StringComparer comparer = StringComparer.OrdinalIgnoreCase;
return 0 == comparer.Compare(hashOfInput, hash);
}
StringBuilder sb= new StringBuilder();
for (int i = 0; i < tmpHash.Length; i++)
{
sb.Append(tmpHash[i].ToString("x2"));
}
public static string GetMD5(string encryptString)
{
var passByteCrypt = new MD5CryptoServiceProvider().ComputeHash(Encoding.UTF8.GetBytes(encryptString));
return ByteArrayToString(passByteCrypt);
}
public static string ByteArrayToString(byte[] bytes)
{
var output = new StringBuilder(bytes.Length);
foreach (var t in bytes)
{
output.Append(t.ToString("X2"));
}
return output.ToString().ToLower();
}
this is simple md5 ByteCrypt
If you are using a version lower than .NET5 this is a neat way to write it
string.Concat(yourHashBytes.Select(x => x.ToString("X2")))
Here is a condensed version.
private string CreateMD5(string myText)
{
var hash = System.Security.Cryptography.MD5.Create()
.ComputeHash(System.Text.Encoding.ASCII.GetBytes(myText ?? ""));
return string.Join("", Enumerable.Range(0, hash.Length).Select(i => hash[i].ToString("x2")));
}
Related
How to Hex Encode a SHA-256 hash properly in C#?
private static string ToHex(byte[] bytes, bool upperCase)
{
StringBuilder result = new StringBuilder(bytes.Length * 2);
for (int i = 0; i < bytes.Length; i++)
result.Append(bytes[i].ToString(upperCase ? "X2" : "x2"));
return result.ToString();
}
private string hashRequestBody(string reqBody)
{
string hashString;
using (var sha256 = SHA256Managed.Create())
{
var hash = sha256.ComputeHash(Encoding.Default.GetBytes(reqBody));
hashString = ToHex(hash, false);
}
MessageBox.Show(hashString);
return hashString;
}
I did this, but the result is different with bank's sandbox I worked with.
TEST DATA:
{"CorporateID":"BCAAPI2016","SourceAccountNumber":"0201245680","TransactionID":"00000001","TransactionDate":"2017-09-13","ReferenceID":"refID","CurrencyCode":"IDR","Amount":"10000","BeneficiaryAccountNumber":"0201245681","Remark1":"Transfer Test","Remark2":"Online Transfer"}
Bank's sandbox result: e9d06986c1ed6b063bf59aa873030013725c518631deef2b2147e614017c2141
Mine: 1c83acc42cf905ca8afba27ef0640c70ad2856a366b57c17cf16f2894327676e
I've seen several solutions to this problem, but your code is the most elegant. I slightly re-factored it and tested it for this answer. I also get the hash:
1c83acc42cf905ca8afba27ef0640c70ad2856a366b57c17cf16f2894327676e
See working fiddle here: https://dotnetfiddle.net/QbsKTc
Perhaps this hash is different to the bank's because you changed the JSON string to remove private data?
using System;
using System.Security.Cryptography;
using System.Text;
public class Program
{
public static void Main()
{
Console.WriteLine(SHA256HexHashString("{\"CorporateID\":\"BCAAPI2016\",\"SourceAccountNumber\":\"0201245680\",\"TransactionID\":\"00000001\",\"TransactionDate\":\"2017-09-13\",\"ReferenceID\":\"refID\",\"CurrencyCode\":\"IDR\",\"Amount\":\"10000\",\"BeneficiaryAccountNumber\":\"0201245681\",\"Remark1\":\"Transfer Test\",\"Remark2\":\"Online Transfer\"}"));
}
private static string ToHex(byte[] bytes, bool upperCase)
{
StringBuilder result = new StringBuilder(bytes.Length * 2);
for (int i = 0; i < bytes.Length; i++)
result.Append(bytes[i].ToString(upperCase ? "X2" : "x2"));
return result.ToString();
}
private static string SHA256HexHashString(string StringIn)
{
string hashString;
using (var sha256 = SHA256Managed.Create())
{
var hash = sha256.ComputeHash(Encoding.Default.GetBytes(StringIn));
hashString = ToHex(hash, false);
}
return hashString;
}
}
More simple solution
public string SHA256HexHashString(string input)
{
using var sha256 = SHA256.Create();
var bytes = Encoding.UTF8.GetBytes(input);
var hash = sha256.ComputeHash(bytes);
var hex = BitConverter.ToString(hash).Replace("-", "").ToLower();
return hex;
}
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.
I have tried hashing a string in PHP using MD5 and the same in C#, but the results are different if the string contains special characters. Can someone explain me how to get this matched?
Here is my code in C#:
MD5 md5 = new MD5CryptoServiceProvider();
//compute hash from the bytes of text
md5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(text));
//get hash result after compute it
byte[] result = md5.Hash;
StringBuilder strBuilder = new StringBuilder();
for (int i = 0; i < result.Length; i++)
{
//change it into 2 hexadecimal digits
//for each byte
strBuilder.Append(result[i].ToString("x2"));
}
return strBuilder.ToString();
My string is "Samuel2989&*" as a string.
Outputs:
PHP: 957915b9c9a8fb65e13fe1dc9a8b86d4
C# : f5ee451f7eb4587da00d4aa31ae1c378
Can you try with this method and tell me if it worked out for you?
public static string MD5Hash(string input)
{
System.Security.Cryptography.MD5CryptoServiceProvider x = new System.Security.Cryptography.MD5CryptoServiceProvider();
byte[] bs = System.Text.Encoding.UTF8.GetBytes(input);
bs = x.ComputeHash(bs);
System.Text.StringBuilder s = new System.Text.StringBuilder();
foreach (byte b in bs)
{
s.Append(b.ToString("x2").ToLower());
}
string password = s.ToString();
return password;
}
I'd like to ask for the equivalents of the following VB6 code in C#
As you can see here, I'm trying to make a basic encryption code which converts each letter to bytes and then again convert to Hexadecimal...
Public Function Encrypt(s As String) As String
Dim bytArray() As Byte
bytArray = StrConv(s, vbFromUnicode)
For i = LBound(bytArray) To UBound(bytArray)
Encrypt = Encrypt & Hex(bytArray(i))
Next i
End Function
I've tried a little bit of C# but I can't figure it out...
private string encrypt(string s, byte[] bytArray, string t)
{
bytArray = ????;
for(int i = 0; i < s.Length ????; i++{
t += Hex(bytArray[i]); ????
}
return t;
}
I'm sorry I am really a novice in C# and I've gotten so adapted in BASIC that I don't know how to get used in other languages... please help... thanks!
if you want to encrypt the string i think you'd better use XOR (^ in C#) than &.
Here is the example of something like you've wrote:
using System.IO;
using System;
using System.Text;
class Program
{
static void Main()
{
string input = "test input";
byte[] key = new byte[input.Length];
Random r = new Random(DateTime.Now.Millisecond);
for (int i = 0; i < key.Length; i++)
{
key[i] = (byte)r.Next();
}
var result = Encrypt(input, key);
Console.WriteLine(result);
}
static string Encrypt(string inp, byte[] key){
StringBuilder sb = new StringBuilder();
for (int i = 0; i < inp.Length; i++)
{
sb.Append(inp[i] & key[i]);
}
return sb.ToString();
}
}
you will not be able to decode the string using &
C# has System.Security.Cryptography namespace with encryption algorithms
Define "encrypt". Do you really just mean "obfuscate"? Are you trying to replicate the original VB6 exactly? Or simply achieve a similar effect?
One possible approach (this will encode to Unicode bytes):
using System.Text;
string Encrypt(string text)
{
return string.Concat(
Encoding.Unicode.GetBytes(text).Select(b => b.ToString("x2")));
}
Another possibility (this will be exactly the same result as the VB6 code):
using System.Text;
string Encrypt(string text)
{
return string.Concat(
Encoding.Default.GetBytes(text).Select(b => b.ToString("x2")));
}
The only difference between the two is which text encoding is used to convert to bytes.
exact version
VB.NET
Public Function Encrypt(s As String) As String
Encrypt = String.Empty
Dim byteArray() As Byte = System.Text.Encoding.Unicode.GetBytes(s)
For Each b As Byte In byteArray
Encrypt &= Hex(b)
Next
End Function
C#
static string Encrypt(string s)
{
string encrypt = "";
byte[] byteArray = System.Text.Encoding.Unicode.GetBytes(s);
foreach (byte b in byteArray)
{
encrypt += String.Format("{0:x}", System.Convert.ToInt64(b));
}
return encrypt;
}
short version - requires string formatting
VB.NET
Public Function Encrypt(s As String) As String
Dim byteArray() As Byte = System.Text.Encoding.Unicode.GetBytes(s)
Encrypt = BitConverter.ToString(byteArray)
End Function
C#
static string Encrypt(string s)
{
byte[] byteArray = System.Text.Encoding.Unicode.GetBytes(s);
string encrypt = BitConverter.ToString(byteArray);
return encrypt;
}
this is my problem,
i have this code that accepts clean text with passwords and returns Base64MD5 hashes
private static string GetMd5Base64Pass(string userpwd)
{
MD5 md5 = new MD5CryptoServiceProvider();
return Convert.ToBase64String(md5.ComputeHash(Encoding.ASCII.GetBytes(userpwd)));
}
And i need to reuse it to accept MD5 string hashes and return in Base64MD5.
i tried to do this:
private static string GetMd5Base64PassMD5(string userpwd)
{
MD5 md5 = new MD5CryptoServiceProvider();
return Convert.ToBase64String(Encoding.ASCII.GetBytes(userpwd));
}
but the returns are completely different.
already tried to convert the string to bytearray, didn't work.
I need to insert one string with 32bits MD5, and return it in Base64String.
thks
------------------------------ Edited
Example:
Password is 123123:
MD5 is: 4297f44b13955235245b2497399d7a93
Base64String of MD5 is: Qpf0SxOVUjUkWySXOZ16kw==
I need to get
this: Qpf0SxOVUjUkWySXOZ16kw==
from
this hash string
4297f44b13955235245b2497399d7a93
public static string ConvertHexStringToBase64(string hexString)
{
byte[] buffer = new byte[hexString.Length / 2];
for (int i = 0; i < hexString.Length; i++)
{
buffer[i / 2] = Convert.ToByte(Convert.ToInt32(hexString.Substring(i, 2), 16));
i += 1;
}
string res = Convert.ToBase64String(buffer);
return res;
}
this receives md5 string hashes and transforms it to Base64 Hex