Hash Functions

GetHash returns the hash value of a byte array.
GetHashStr returns the hash value of a string.

These functions can use any of the hash classes from the System.Security.Cryptography namespace, e.g. MD5, SHA1, SHA256, SHA512.

//C#
using System;
using System.Security.Cryptography;
using System.Text;

namespace ExpressionSoftware.Security.Crypt
{
    public static class Hash
    {
        public static byte[] GetHash(byte[] bs, Type hashType)
        {
            return HashAlgorithm.Create(hashType.Name).ComputeHash(bs);
        }
        
        public static byte[] GetHashStr(string input, Type hashType)
        {
            byte[] bs = Encoding.UTF8.GetBytes(input);
            return GetHash(bs, hashType);
        }
    }
}

//F# v1.9.7.8
namespace ExpressionSoftware.Security.Crypt
open System
open System.Security.Cryptography
open System.Text

module Hash =
  let GetHash(bs:byte[], hashType:Type) =
    HashAlgorithm.Create(hashType.Name).ComputeHash bs

  let GetHashStr(input:string, hashType:Type) =
    Encoding.UTF8.GetBytes input
    |> (fun bs -> GetHash(bs, hashType))

#PowerShell
function getHash($bs, $hashType)
{
  $hashType::create().computeHash($bs)
}

function getHashStr($inputStr, $hashType)
{
  getHash ([system.text.encoding]::utf8.getBytes($inputStr)) $hashType
}

Examples

//C#
byte[] bs = Encoding.UTF8.GetBytes("foo");
byte[] hash = Hash.GetHash(bs, typeof(SHA1));
Debug.WriteLine(Byte.BytesToString(hash, "{0} "));
11 238 199 181 234 63 15 219 201 93 13 212 127 60 91 194 117 218 138 51  //output

//F#
let hash = Hash.GetHashStr("foo", typeof<SHA1>)
Byte.BytesToString(hash, "{0:x} ")
|> (fun s -> printfn "%s" s)
b ee c7 b5 ea 3f f db c9 5d d d4 7f 3c 5b c2 75 da 8a 33  //output

#PowerShell
$hashType = [system.security.cryptography.SHA1]
$hash = getHashStr 'foo' $hashType
bytesToString $hash '{0:X}'
BEEC7B5EA3FFDBC95DDD47F3C5BC275DA8A33  #output

Bytes to String Function

BytesToString returns a byte array as a formatted string.

02-05-10 This function has been replaced with a generic version - Generic Array to String Function.

//C#
using System.Text;

namespace ExpressionSoftware.System
{
    public static class Byte
    {
        public static string BytesToString(byte[] bs, string format)
        {
            var sb = new StringBuilder(bs.Length * 4);
            foreach (byte b in bs)
            {
                sb.AppendFormat(format, b);
            }
            return sb.ToString();
        }
    }
}

//F# v1.9.7.8
namespace ExpressionSoftware.System
open System.Text

module Byte =
  let BytesToString(bs:byte[], format:string) =
    let sb = new StringBuilder(bs.Length * 4)
    bs |> Array.iter(fun b -> sb.AppendFormat(format, b) |> ignore)
    sb.ToString()

#PowerShell
function bytesToString($bs, $format)
{
  $bs | %{$result += ($format -f $_)}
  $result
}

Examples

//C#
byte[] bs = { 102, 111, 111 };
Debug.WriteLine(Byte.BytesToString(bs, "{0}"));  //default format
102111111  //output

//F#
let bs = [|102uy; 111uy; 111uy|]
Byte.BytesToString(bs, "{0:d4}-")  //4 digit width format
|> (fun s -> printfn "%s" s)
0102-0111-0111-  //output

#PowerShell
[byte[]]$bs = 102,111,111
bytesToString $bs '{0:x} ' #hex format
66 6f 6f  #output

Listing Users From the Windows Event Log

GetEventLogUsers returns a list of users from the Windows EventLogs, e.g. Application, Security, System. This function returns the entire dataset, unsorted. See examples for sorting and returning distinct lists.

Note: This function works on Windows XP, but not Window Server 2008.

//C#
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace ExpressionSoftware.EventLogs
{
    public static class EventLogQuery
    {
        public static IEnumerable GetEventLogUsers(string logName)
        {
            EventLog log = new EventLog(logName);
            var users = from e in log.Entries.Cast()
                        select e.UserName;
            return users;
        }
    }
}

//F# v1.9.7.8
namespace ExpressionSoftware.EventLogs
open System.Diagnostics

module EventLogQuery =
  let GetEventLogUsers logName =
    let log = new EventLog(logName)
    log.Entries
    |> Seq.cast
    |> Seq.map (fun x -> x.UserName)

#PowerShell
function getEventLogUsers($logName)
{
  $log = new-object system.diagnostics.eventLog($logName)
  $log.entries | %{$_.username}
}

Examples

//C#
var users = EventLogQuery.GetEventLogUsers("security");
users = users.Distinct().OrderBy(u => u);
foreach (string user in users)
{
    Debug.WriteLine(user);
}

//F#
let users = EventLogQuery.GetEventLogUsers "security" |> Seq.distinct |> Seq.sort
for user in users do
  printfn "%s" user

#PowerShell
getEventLogUsers 'security' | sort-object | get-unique

Output

DEV\john
NT AUTHORITY\ANONYMOUS LOGON
NT AUTHORITY\LOCAL SERVICE
NT AUTHORITY\NETWORK SERVICE
NT AUTHORITY\SYSTEM