Imports System.Text.RegularExpressions

Public Class HashValidator
    Public Enum ALGO As Integer
        CRC16 = 4
        CRC32 = 8
        MD5 = 32
        SHA1 = 40
        SHA256 = 64
        SHA384 = 96
        SHA512 = 128
    End Enum

    Public Shared Function IsValid(ByVal Expression As String, ByVal Algorythm As ALGO) As Boolean
        Dim Validator As Regex = Nothing

        Select Case Algorythm
            Case ALGO.CRC16 : Validator = New Regex("^([a-fA-F0-9]){4}$")
            Case ALGO.CRC32 : Validator = New Regex("^([a-fA-F0-9]){8}$")
            Case ALGO.MD5 : Validator = New Regex("^([a-fA-F0-9]){32}$")
            Case ALGO.SHA1 : Validator = New Regex("^([a-fA-F0-9]){40}$")
            Case ALGO.SHA256 : Validator = New Regex("^([a-fA-F0-9]){64}$")
            Case ALGO.SHA384 : Validator = New Regex("^([a-fA-F0-9]){96}$")
            Case ALGO.SHA512 : Validator = New Regex("^([a-fA-F0-9]){128}$")
        End Select

        Return Validator.IsMatch(Expression)
    End Function

    Public Shared Function IsValid(ByVal Expression() As Byte, ByVal Algorythm As ALGO) As Boolean
        Dim TmpValue As String = ""
        Dim HashString As String = ""

        For i As Integer = 0 To Expression.Length - 1
            TmpValue = Hex(Expression(i))
            If Len(TmpValue) = 1 Then TmpValue = "0" & TmpValue
            HashString &= TmpValue
        Next

        Return IsValid(HashString, Algorythm)
    End Function
End Class