Public/ConvertFrom-Base64ToString.ps1

<#
    .SYNOPSIS
        Converts a base64 encoded string to a string.
     
    .DESCRIPTION
        Converts a base64 encoded string to a string.
     
    .PARAMETER String
        A Base64 Encoded String
     
    .PARAMETER Encoding
        The encoding to use for conversion.
        Defaults to UTF8.
        Valid options are ASCII, BigEndianUnicode, Default, Unicode, UTF32, UTF7, and UTF8.
     
    .EXAMPLE
        ConvertFrom-Base64ToString -String 'QSBzdHJpbmc='
 
        A string
     
    .EXAMPLE
        ConvertTo-Base64 -String 'A string','Another string'
 
        QSBzdHJpbmc=
        QW5vdGhlciBzdHJpbmc=
     
    .EXAMPLE
        'QSBzdHJpbmc=' | ConvertFrom-Base64ToString
 
        A string
 
    .EXAMPLE
        'QSBzdHJpbmc=','QW5vdGhlciBzdHJpbmc=' | ConvertFrom-Base64ToString
 
        A string
        Another string
     
    .OUTPUTS
        [String[]]
 
    .LINK
        http://convert.readthedocs.io/en/latest/functions/ConvertFrom-Base64ToString/
#>

function ConvertFrom-Base64ToString
{
    [CmdletBinding(HelpUri = 'http://convert.readthedocs.io/en/latest/functions/ConvertFrom-Base64ToString/')]
    [OutputType('String')]
    param
    (
        [Parameter(
            Mandatory = $true,
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true)]
        [ValidateNotNullOrEmpty()]
        [String[]]
        $String,

        [ValidateSet('ASCII', 'BigEndianUnicode', 'Default', 'Unicode', 'UTF32', 'UTF7', 'UTF8')]
        [String]
        $Encoding = 'UTF8'
    )
    
    begin
    {
        $userErrorActionPreference = $ErrorActionPreference
    }

    process
    {
        foreach ($s in $String)
        {
            try
            {
                $bytes = [System.Convert]::FromBase64String($s)
                [System.Text.Encoding]::$Encoding.GetString($bytes)    
            }
            catch
            {
                Write-Error -ErrorRecord $_ -ErrorAction $userErrorActionPreference
            }
        }
    }
}