A tiny helper C# class that converts an arbitrary string to an hex encoded SHA1 hash.

Sha1Hasher.cs

using System;
using System.Security.Cryptography;

namespace MyNamespace
{
	public class Sha1Hasher
	{
		public static string sha1Hash (string plaintext)
		{
			SHA1 sh1 = SHA1.Create ();
			String hash = "mySaltHere" + plaintext;
			System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
			byte[] bytes = encoding.GetBytes (hash); 
			String hashed = byteArrayToHexString (sh1.ComputeHash (bytes));
			return hashed;
		}

		public static string byteArrayToHexString (byte[] b)
		{
			string result = "";
			for (int i = 0; i < b.Length; i++) {
				result +=
					((b [i] & 0xff) + 0x100).ToString ("x").Substring (1);
			}
			return result;
		}
	}
}