Character generated from SHA-512 hash does not get saved to database - algorithm

Question

I'm hashing a password using SHA512. I'm using Entity Framework Code-First for my ORM.
Hashing Algorithm
public static string CreateSHA512Hash(string pwd, string salt)
{
string saltAndPwd = String.Concat(pwd, salt);
var ae = new ASCIIEncoding();
byte[] hashValue, messageBytes = ae.GetBytes(saltAndPwd);
var sHhash = new SHA512Managed();
hashValue = sHhash.ComputeHash(messageBytes);
sHhash.Dispose();
return ae.GetString(hashValue);
}
Code for generating salt:
//Generate a cryptographic random number.
var rng = new RNGCryptoServiceProvider();
var buff = new byte[size];
rng.GetBytes(buff);
rng.Dispose();
// Return a Base64 string representation of the random number.
return Convert.ToBase64String(buff);
Problem:
For some reason, it seems the hash function would randomly generate some characters, which the ones after those are not saved to the database. In this case (I'm not sure if there are other characters that does this), but it is \0.
For eg. Password: testuser. Salt: uvq5i4CfMcOMjKPkwhhqxw==
Hash generated: ????j???7?o\0?dE??????:???s?x??u?',Vj?mNB??c???4H???vF\bd?T? (copied during dubug mode in visual studio).
But EF actually saves ????j???7?o to the database. If I try to use the text visualizer in debug mode, it cuts it off also. If you noticed, it gets cut off right at the \0. All I could find about it is that its a null character.
Question
How can I save this null character in the database using Entity Framework Code-First? If this can't be saved, how can I prevent the SHA512 from generating these characters for me?

Answer 1

I recommend encoding the hash with Base64 before saving. On the other hand, encoding the salt with Base64 before adding to the password sounds strange.

Answer 2

A SHA-256 hash does not generate characters, it generates bytes. If you want to have a character string, as opposed to a byte array, you need to convert the bytes into a character format. As #wRAR has suggested, Base64 is one common way to do it or else you could just use a hex string.

Answer 3

What you should probably do:
Return the array of bytes for the SHA512 hash not a string.
Use a BINARY(64) database column to hold your hash value.
Why your method doesn't work:
These ASCII strings are NULL terminated
NULL is as you said \0
SHA512 creates a byte array and any byte can be NULL
To answer your specific question:
wRAR above was saying.
return Convert.ToBase64String(hashValue);