SecurityFever

3.0.0

Helpers/Common/Convert-Base32ToByte.ps1

<#
    .SYNOPSIS
        Convert a Base32 (RFC 4648) based string to a byte array.
#>
function Convert-Base32ToByte
{
    [CmdletBinding()]
    [OutputType([System.Byte])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $Base32
    )

    # RFC 4648 Base32 alphabet
    $rfc4648 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'

    $bits = ''

    # Convert each Base32 character to the binary value between starting at
    # 00000 for A and ending with 11111 for 7.
    foreach ($char in $Base32.ToUpper().ToCharArray())
    {
        $bits += [Convert]::ToString($rfc4648.IndexOf($char), 2).PadLeft(5, '0')
    }

    # Convert 8 bit chunks to bytes, ignore the last bits.
    for ($i = 0; $i -le ($bits.Length - 8); $i += 8)
    {
        [Byte] [Convert]::ToInt32($bits.Substring($i, 8), 2)
    }
}