Converting a md5 hash byte array to a string

问题:

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.

回答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);

回答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.

回答3:

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

回答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

回答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.

回答6:

Well, you could use the string constructor that takes bytes and an encoding, but you'll likely get a difficult to manage string out of that since it could contain lots of fun characters (null bytes, newlines, control chars, etc)

The best way to do this would be to encode it with base 64 to get a nice string that's easy to work with:

string s = Convert.ToBase64String(bytes);

And to go from that string back to a byte array:

byte[] bytes = Convert.FromBase64String(s);

回答7:

For anyone interested a Nuget package I created called CryptoStringify allows you to convert a string to a hashed string using a nice clean syntax, without having to play around with byte arrays:

using (MD5 md5 = MD5.Create())
{
    string strHashedPassword = md5.Hash(password);
}

It's an extension method on HashAlgorithm and KeyedHashAlgorithm so works on SHA1, HMACSHA1, SHA256 etc too.

https://www.nuget.org/packages/cryptostringify