Converting a md5 hash byte array to a string

c# hash cryptography md5 cryptographic-hash-function

87,440

Solution 1

   public static string ToHex(this 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();
    }

You can then call it as an extension method:

string hexString = byteArray.ToHex(false);

Solution 2

I always found this to be the most convenient:

string hashPassword = BitConverter.ToString(byteHashedPassword).Replace("-","");

For some odd reason BitConverter likes to put dashes between bytes, so the replace just removes them.

Update: If you prefer "lowercase" hex, just do a .ToLower() and boom.

Do note that if you are doing this as a tight loop and many ops this could be expensive since there are at least two implicit string casts and resizes going on.

Solution 3

You can use Convert.ToBase64String and Convert.FromBase64String to easily convert byte arrays into strings.

Solution 4

If you're in the 'Hex preference' camp you can do this. This is basically a minimal version of the answer by Philippe Leybaert.

string.Concat(hash.Select(x => x.ToString("X2")))

B1DB2CC0BAEE67EA47CFAEDBF2D747DF

Solution 5

Well as it is a hash, it has possibly values that cannot be shown in a normal string, so the best bet is to convert it to Base64 encoded string.

string s = Convert.ToBase64String(bytes);

and use

byte[] bytes = Convert.FromBase64(s);

to get the bytes back.

View more solutions

87,440

Blankman

... .. . blank

Updated on May 29, 2020

Comments

Blankman almost 4 years
How can I convert the hashed result, which is a byte array, to a string?
```
byte[] bytePassword = Encoding.UTF8.GetBytes(password);

using (MD5 md5 = MD5.Create())
{
    byte[] byteHashedPassword = md5.ComputeHash(bytePassword);
} 
```
I need to convert byteHashedPassword to a string.
- Kerrmiter about 3 years
  
  MD5 is deprecated. It is inherently broken as it does not reach the standards of collision or preimage resistance. For passwords, it's better to use iterated key-derivation functions such as Argon2 or PDKDF2.
Blankman about 14 years

what is the significance of upper casing?
Philippe Leybaert about 14 years

a matter of preference. That's why I added a parameter to my method, so the caller can choose
John Kugelman about 14 years

It's the difference between c0de and C0DE, that's all.
Eric Petroelje about 14 years

No need to reinvent the wheel when you already have Convert.ToBase64String()
Blankman about 14 years

oh ok, I thought there was more too it! how does your answer differ from Convert.ToBase64String(bytes)?
Philippe Leybaert about 14 years

A Base64 string is shorter. It uses all letters of the alphabet, digits and a few punctuation characters, so it's not hexadecimal. Base64 uses 4 characters for 3 bytes, while a hex string uses 6 characters for 3 bytes.
Philippe Leybaert about 14 years

@Eric: there are situations where Base64 is not a good choice because of the extra punctuation characters that are used (passing it in a URL for example)
sonjz almost 11 years

does the same as @PhilippeLeybaert solution, but in one-line.