SHA1 hashing in SQLite: how?

There is no such function built into SQLite3.

But you could define a user function e.g. with sqlite3_create_function if you're using the C interface, and implement SHA-1 with that. (But if you're having a programmable interface perhaps you could just SHA-1 the password outside of the SQL engine.)

You could also try to find / create an extension and load with the load_extension function, but I don't have experience on that.

Edit:

• See this answer on SQLiteFunction Simple Not Working for how to define a custom function with System.Data.SQLite in C#.
• Use System.Security.Cryptography.SHA1 to compute the SHA-1 hash.

SQLite does not come with SHA1, but it is relatively easily to add. You didn't say what language, you're using, but you can look at the C documentation for create_function and sqlite3_result. You can also take a look at this example of how to add SHA1 to SQLite using Ruby.

With System.Data.SQLite, they're called user-defined functions. You can look at this example on the main site.

You can create a custom function for SHA1 in C# like this:

[SQLiteFunction(Name = "Sha1", Arguments = 1, FuncType = FunctionType.Scalar)]
public class Sha1 : SQLiteFunction
{
    public override object Invoke(object[] args)
    {
        var buffer = args[0] as byte[];

        if ( buffer == null )
        {
            var s = args[0] as string;

            if ( s != null )
                buffer = Encoding.Unicode.GetBytes(s);
        }

        if ( buffer == null )
            return null;

        using ( var sha1 = SHA1.Create() )
        {
            return sha1.ComputeHash(buffer);
        }
    }
}

This function can be called for binary data or strings. Strings are hashed in their Unicode representation. This should match SQL Server.

The function can be called like this:

select sha1('abc')
select sha1(x'010203')