Computing hash SHA1 in C# [duplicate]

Question

This question already has answers here:

How do I calculate the equivalent to SQL Server (hashbytes('SHA1',[ColumnName])) in C#? (4 answers)

Closed 9 years ago.

In a legacy system we have a password made by the following in SQL Server.

select HashBytes('SHA1' , Convert(nvarchar(4000),'MyPassword'))

Now, cause a lot of non-functional requirements, we have to compute the same password in C#.

My best try was:

public static byte[] CalculateSHA1(string text)
{
    byte[] buffer = UTF8Encoding.Default.GetBytes(text);
    SHA1CryptoServiceProvider cryptoTransformSHA1 = new SHA1CryptoServiceProvider();
    return cryptoTransformSHA1.ComputeHash(buffer);
}

But it returns a different array of bytes than the SQL Code returns.

Someone could help me?

Answer 1

Change UTF8Encoding.Default to Encoding.Unicode and the results will match. SQL Server HashBytes function uses UTF16 when converting NCHARs and NVARCHARs to bytes before performing the actual hash.