Modules/CertificateDsc.Common/CertificateDsc.Common.psm1

# Import the Networking Resource Helper Module
Import-Module -Name (Join-Path -Path (Split-Path -Path $PSScriptRoot -Parent) `
        -ChildPath (Join-Path -Path 'CertificateDsc.ResourceHelper' `
            -ChildPath 'CertificateDsc.ResourceHelper.psm1'))

# Import Localization Strings
$localizedData = Get-LocalizedData `
    -ResourceName 'CertificateDsc.Common' `
    -ResourcePath $PSScriptRoot

<#
    .SYNOPSIS
    Validates the existence of a file at a specific path.
 
    .PARAMETER Path
    The location of the file. Supports any path that Test-Path supports.
 
    .PARAMETER Quiet
    Returns $false if the file does not exist. By default this function throws
    an exception if the file is missing.
 
    .EXAMPLE
    Test-CertificatePath -Path '\\server\share\Certificates\mycert.cer'
 
    .EXAMPLE
    Test-CertificatePath -Path 'C:\certs\my_missing.cer' -Quiet
 
    .EXAMPLE
    'D:\CertRepo\a_cert.cer' | Test-CertificatePath
 
    .EXAMPLE
    Get-ChildItem -Path D:\CertRepo\*.cer |
        Test-CertificatePath
#>

function Test-CertificatePath
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true,
            ValueFromPipeline)]
        [System.String[]]
        $Path,

        [Parameter()]
        [Switch]
        $Quiet
    )

    Process
    {
        foreach ($pathNode in $Path)
        {
            if ($pathNode | Test-Path -PathType Leaf)
            {
                $true
            }
            elseif ($Quiet)
            {
                $false
            }
            else
            {
                New-InvalidArgumentException `
                    -Message ($LocalizedData.FileNotFoundError -f $pathNode) `
                    -ArgumentName 'Path'
            }
        }
    }
} # end function Test-CertificatePath

<#
    .SYNOPSIS
    Validates whether a given certificate is valid based on the hash algoritms available on the
    system.
 
    .PARAMETER Thumbprint
    One or more thumbprints to Test.
 
    .PARAMETER Quiet
    Returns $false if the thumbprint is not valid. By default this function throws an exception if
    validation fails.
 
    .EXAMPLE
    Test-Thumbprint `
        -Thumbprint fd94e3a5a7991cb6ed3cd5dd01045edf7e2284de
 
    .EXAMPLE
    Test-Thumbprint `
        -Thumbprint fd94e3a5a7991cb6ed3cd5dd01045edf7e2284de,0000e3a5a7991cb6ed3cd5dd01045edf7e220000 `
        -Quiet
 
    .EXAMPLE
    Get-ChildItem -Path Cert:\LocalMachine -Recurse |
        Where-Object -FilterScript { $_.Thumbprint } |
        Select-Object -Expression Thumbprint |
        Test-Thumbprint -Verbose
#>

function Test-Thumbprint
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true,
            ValueFromPipeline)]
        [ValidateNotNullOrEmpty()]
        [System.String[]]
        $Thumbprint,

        [Parameter()]
        [Switch]
        $Quiet
    )

    Begin
    {
        # Get FIPS registry key
        $fips = [System.Int32] (Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Lsa\FipsAlgorithmPolicy' -ErrorAction SilentlyContinue).Enabled

        <#
            Get a list of Hash Providers, but exclude assemblies that set DefinedTypes to null instead of an empty array.
            Otherwise, the call to GetTypes() fails.
        #>

        $allHashProviders = ([System.AppDomain]::CurrentDomain.GetAssemblies() | Where-Object { $null -ne $_.DefinedTypes}).GetTypes()

        if ($fips -eq $true)
        {
            # Support only FIPS compliant Hash Algorithms
            $hashProviders = $allHashProviders | Where-Object -FilterScript {
                    $_.BaseType.BaseType -eq [System.Security.Cryptography.HashAlgorithm] -and
                    ($_.Name -cmatch 'Provider$' -and $_.Name -cnotmatch 'MD5')
            }
        }
        else
        {
            $hashProviders = $allHashProviders | Where-Object -FilterScript {
                    $_.BaseType.BaseType -eq [System.Security.Cryptography.HashAlgorithm] -and
                    ($_.Name -cmatch 'Managed$' -or $_.Name -cmatch 'Provider$')
            }
        }

        # Get a list of all Valid Hash types and lengths into an array
        $validHashes = @()

        foreach ($hashProvider in $hashProviders)
        {
            $bitSize = ( New-Object -TypeName $hashProvider ).HashSize
            $validHash = New-Object `
                -TypeName PSObject `
                -Property @{
                Hash      = $hashProvider.BaseType.Name
                BitSize   = $bitSize
                HexLength = $bitSize / 4
            }
            $validHashes += @( $validHash )
        }
    }

    Process
    {
        foreach ($hash in $Thumbprint)
        {
            $isValid = $false

            foreach ($algorithm in $validHashes)
            {
                if ($hash -cmatch "^[a-fA-F0-9]{$($algorithm.HexLength)}$")
                {
                    $isValid = $true
                }
            }

            if ($Quiet -or $isValid)
            {
                $isValid
            }
            else
            {
                New-InvalidOperationException `
                    -Message ($LocalizedData.InvalidHashError -f $hash)
            }
        }
    }
} # end function Test-Thumbprint

<#
    .SYNOPSIS
    Locates one or more certificates using the passed certificate selector parameters.
 
    If more than one certificate is found matching the selector criteria, they will be
    returned in order of descending expiration date.
 
    .PARAMETER Thumbprint
    The thumbprint of the certificate to find.
 
    .PARAMETER FriendlyName
    The friendly name of the certificate to find.
 
    .PARAMETER Subject
    The subject of the certificate to find.
 
    .PARAMETER DNSName
    The subject alternative name of the certificate to export must contain these values.
 
    .PARAMETER Issuer
    The issuer of the certificate to find.
 
    .PARAMETER KeyUsage
    The key usage of the certificate to find must contain these values.
 
    .PARAMETER EnhancedKeyUsage
    The enhanced key usage of the certificate to find must contain these values.
 
    .PARAMETER Store
    The Windows Certificate Store Name to search for the certificate in.
    Defaults to 'My'.
 
    .PARAMETER AllowExpired
    Allows expired certificates to be returned.
 
#>

function Find-Certificate
{
    [CmdletBinding()]
    [OutputType([System.Security.Cryptography.X509Certificates.X509Certificate2[]])]
    param
    (
        [Parameter()]
        [System.String]
        $Thumbprint,

        [Parameter()]
        [System.String]
        $FriendlyName,

        [Parameter()]
        [System.String]
        $Subject,

        [Parameter()]
        [System.String[]]
        $DNSName,

        [Parameter()]
        [System.String]
        $Issuer,

        [Parameter()]
        [System.String[]]
        $KeyUsage,

        [Parameter()]
        [System.String[]]
        $EnhancedKeyUsage,

        [Parameter()]
        [System.String]
        $Store = 'My',

        [Parameter()]
        [Boolean]
        $AllowExpired = $false
    )

    $certPath = Join-Path -Path 'Cert:\LocalMachine' -ChildPath $Store

    if (-not (Test-Path -Path $certPath))
    {
        # The Certificte Path is not valid
        New-InvalidArgumentException `
            -Message ($LocalizedData.CertificatePathError -f $certPath) `
            -ArgumnentName 'Store'
    } # if

    # Assemble the filter to use to select the certificate
    $certFilters = @()

    if ($PSBoundParameters.ContainsKey('Thumbprint'))
    {
        $certFilters += @('($_.Thumbprint -eq $Thumbprint)')
    } # if

    if ($PSBoundParameters.ContainsKey('FriendlyName'))
    {
        $certFilters += @('($_.FriendlyName -eq $FriendlyName)')
    } # if

    if ($PSBoundParameters.ContainsKey('Subject'))
    {
        $certFilters += @('($_.Subject -eq $Subject)')
    } # if

    if ($PSBoundParameters.ContainsKey('Issuer'))
    {
        $certFilters += @('($_.Issuer -eq $Issuer)')
    } # if

    if (-not $AllowExpired)
    {
        $certFilters += @('(((Get-Date) -le $_.NotAfter) -and ((Get-Date) -ge $_.NotBefore))')
    } # if

    if ($PSBoundParameters.ContainsKey('DNSName'))
    {
        $certFilters += @('(@(Compare-Object -ReferenceObject $_.DNSNameList.Unicode -DifferenceObject $DNSName | Where-Object -Property SideIndicator -eq "=>").Count -eq 0)')
    } # if

    if ($PSBoundParameters.ContainsKey('KeyUsage'))
    {
        $certFilters += @('(@(Compare-Object -ReferenceObject ($_.Extensions.KeyUsages -split ", ") -DifferenceObject $KeyUsage | Where-Object -Property SideIndicator -eq "=>").Count -eq 0)')
    } # if

    if ($PSBoundParameters.ContainsKey('EnhancedKeyUsage'))
    {
        $certFilters += @('(@(Compare-Object -ReferenceObject ($_.EnhancedKeyUsageList.FriendlyName) -DifferenceObject $EnhancedKeyUsage | Where-Object -Property SideIndicator -eq "=>").Count -eq 0)')
    } # if

    # Join all the filters together
    $certFilterScript = '(' + ($certFilters -join ' -and ') + ')'

    Write-Verbose `
        -Message ($LocalizedData.SearchingForCertificateUsingFilters -f $store, $certFilterScript) `
        -Verbose

    $certs = Get-ChildItem -Path $certPath |
        Where-Object -FilterScript ([ScriptBlock]::Create($certFilterScript))

    # Sort the certificates
    if ($certs.count -gt 1)
    {
        $certs = $certs | Sort-Object -Descending -Property 'NotAfter'
    } # if

    return $certs
} # end function Find-Certificate

<#
    .SYNOPSIS
    Get CDP container.
 
    .DESCRIPTION
    Gets the configuration data partition from the active directory configuration
    naming context.
 
    .PARAMETER DomainName
    The domain name.
#>

function Get-CdpContainer
{
    [cmdletBinding()]
    [OutputType([psobject])]
    param
    (
        [Parameter()]
        [System.String]
        $DomainName
    )

    if (-not $DomainName)
    {
        $configContext = ([ADSI]'LDAP://RootDSE').configurationNamingContext

        if (-not $configContext)
        {
            # The computer is not domain joined
            New-InvalidOperationException `
                -Message ($LocalizedData.DomainNotJoinedError)
        }
    }
    else
    {
        $ctx = New-Object -TypeName System.DirectoryServices.ActiveDirectory.DirectoryContext('Domain', $DomainName)
        $configContext = 'CN=Configuration,{0}' -f ([System.DirectoryServices.ActiveDirectory.Domain]::GetDomain($ctx).GetDirectoryEntry().distinguishedName[0])
    }

    Write-Verbose `
        -Message ($LocalizedData.ConfigurationNamingContext -f $configContext.toString()) `
        -Verbose

    $cdpContainer = [ADSI]('LDAP://CN=CDP,CN=Public Key Services,CN=Services,{0}' -f $configContext.toString())

    return $cdpContainer
} # end function Get-CdpContainer

<#
    .SYNOPSIS
    Automatically locate a certificate authority in Active Directory
 
    .DESCRIPTION
    Automatically locates a certificate autority in Active Directory environments
    by leveraging ADSI to look inside the container CDP and subsequently trying to
    certutil -ping every located CA until one is found.
 
    .PARAMETER DomainName
    The domain name of the domain that will be used to locate the CA. Can be left
    empty to use the current domain.
#>

function Find-CertificateAuthority
{
    [cmdletBinding()]
    [OutputType([System.Management.Automation.PSObject])]
    param
    (
        [Parameter()]
        [System.String]
        $DomainName
    )

    Write-Verbose `
        -Message ($LocalizedData.StartLocateCAMessage) `
        -Verbose

    $cdpContainer = Get-CdpContainer @PSBoundParameters -ErrorAction Stop

    $caFound = $false

    foreach ($item in $cdpContainer.Children)
    {
        if (-not $caFound)
        {
            $caServerFQDN = ($item.distinguishedName -split '=|,')[1]
            $caRootName = ($item.Children.distinguishedName -split '=|,')[1]

            $certificateAuthority = [PSObject] @{
                CARootName   = $caRootName
                CAServerFQDN = $caServerFQDN
            }

            if (Test-CertificateAuthority `
                    -CARootName $caRootName `
                    -CAServerFQDN $caServerFQDN)
            {
                $caFound = $true
                break
            }
        }
    }

    if ($caFound)
    {
        Write-Verbose `
            -Message ($LocalizedData.CaFoundMessage -f $certificateAuthority.CAServerFQDN, $certificateAuthority.CARootName) `
            -Verbose

        return $certificateAuthority
    }
    else
    {
        New-InvalidOperationException `
            -Message ($LocalizedData.NoCaFoundError)
    }
} # end function Find-CertificateAuthority

<#
    .SYNOPSIS
    Wraps a single ADSI command to get the domain naming context so it can be mocked.
#>

function Get-DirectoryEntry
{
    [CmdletBinding()]
    param ()

    return ([adsi] 'LDAP://RootDSE').Get('rootDomainNamingContext')
}

<#
    .SYNOPSIS
    Test to see if the specified ADCS CA is available.
 
    .PARAMETER CAServerFQDN
    The FQDN of the ADCS CA to test for availability.
 
    .PARAMETER CARootName
    The name of the ADCS CA to test for availability.
#>

function Test-CertificateAuthority
{
    [cmdletBinding()]
    [OutputType([System.Boolean])]
    param
    (
        [Parameter()]
        [System.String]
        $CAServerFQDN,

        [Parameter()]
        [System.String]
        $CARootName
    )

    Write-Verbose `
        -Message ($LocalizedData.StartPingCAMessage) `
        -Verbose

    $locatorInfo = New-Object -TypeName System.Diagnostics.ProcessStartInfo
    $locatorInfo.FileName = 'certutil.exe'
    $locatorInfo.Arguments = ('-ping "{0}\{1}"' -f $CAServerFQDN, $CARootName)

    # Certutil does not make use of standard error stream
    $locatorInfo.RedirectStandardError = $false
    $locatorInfo.RedirectStandardOutput = $true
    $locatorInfo.UseShellExecute = $false
    $locatorInfo.CreateNoWindow = $true

    $locatorProcess = New-Object -TypeName System.Diagnostics.Process
    $locatorProcess.StartInfo = $locatorInfo

    $null = $locatorProcess.Start()
    $locatorOut = $locatorProcess.StandardOutput.ReadToEnd()
    $null = $locatorProcess.WaitForExit()

    Write-Verbose `
        -Message ($LocalizedData.CaPingMessage -f $locatorProcess.ExitCode, $locatorOut) `
        -Verbose

    if ($locatorProcess.ExitCode -eq 0)
    {
        Write-Verbose `
            -Message ($LocalizedData.CaOnlineMessage -f $CAServerFQDN, $CARootName) `
            -Verbose

        return $true
    }
    else
    {
        Write-Verbose `
            -Message ($LocalizedData.CaOfflineMessage -f $CAServerFQDN, $CARootName) `
            -Verbose

        return $false
    }
} # end function Test-CertificateAuthority

<#
    .SYNOPSIS
    Get certificate template names from Active Directory for x509 certificates.
 
    .DESCRIPTION
    Gets the certificate templates from Active Directory by using a
    DirectorySearcher object to find all objects with an objectClass
    of pKICertificateTemplate from the search root of
    CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration
 
    .NOTES
    The domain variable is populated based on the domain of the user running the
    function. When run as System this will return the domain of computer.
    Normally this won't make any difference unless the user is from a foreign
    domain.
#>

function Get-CertificateTemplatesFromActiveDirectory
{
    [CmdletBinding()]
    [OutputType([PSCustomObject[]])]
    param ()

    try
    {
        $domain   = Get-DirectoryEntry
        $searcher = New-Object -TypeName DirectoryServices.DirectorySearcher

        $searcher.Filter     = '(objectclass=pKICertificateTemplate)'
        $searcher.SearchRoot = 'LDAP://CN=Certificate Templates,CN=Public Key Services,CN=Services,CN=Configuration,{0}' -f $domain

        $searchResults = $searcher.FindAll()
    }
    catch
    {
        Write-Verbose -Message $_.Exception.Message
        Write-Warning -Message $LocalizedData.ActiveDirectoryTemplateSearch
    }

    $adTemplates = @()

    foreach ($searchResult in $searchResults)
    {
        $templateData = @{}
        $properties   =  New-Object -TypeName Object[] -ArgumentList $searchResult.Properties.Count

        $searchResult.Properties.CopyTo($properties, 0)
        $properties.ForEach({
            $templateData[$_.Name] = ($_.Value | Out-String).Trim()
        })

        $adTemplates += [PSCustomObject] $templateData
    }

    return $adTemplates
}

<#
    .SYNOPSIS
    Gets information about the certificate template.
 
    .DESCRIPTION
    This function returns the information about the certificate template by retreiving
    the available templates from Active Directory and matching the formatted certificate
    template name against this list.
    In addition to the template name the display name, template OID, the major version
    and minor version is also returned.
 
    .PARAMETER FormattedTemplate
    The text from the certificate template extension, retrieved from
    Get-CertificateTemplateText.
#>

function Get-CertificateTemplateInformation
{
    [OutputType([PSCustomObject])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $FormattedTemplate
    )

    $templateInformation = @{}

    switch -Regex ($FormattedTemplate)
    {
        <#
            Example of the certificate extension template text
 
            Template=Display Name 1(1.3.6.1.4.1.311.21.8.5734392.6195358.14893705.12992936.3444946.62.3384218.1234567)
            Major Version Number=100
            Minor Version Number=5
 
            If the Display Name of the template has not been found then FormattedText would like something like this.
 
            Template=1.3.6.1.4.1.311.21.8.5734392.6195358.14893705.12992936.3444946.62.3384218.1234567
            Major Version Number=100
            Minor Version Number=5
 
            The Name of the template is found by matching the OID or the Display Name against the list of temples in AD.
        #>


        'Template=(?:(?<DisplayName>.+)\((?<Oid>[\d.]+)\))|(?<Oid>[\d.]+)\s*Major\sVersion\sNumber=(?<MajorVersion>\d+)\s*Minor\sVersion\sNumber=(?<MinorVersion>\d+)'
        {
            [Array] $adTemplates = Get-CertificateTemplatesFromActiveDirectory

            if ([System.String]::IsNullOrEmpty($Matches.DisplayName))
            {
                $template = $adTemplates.Where({
                    $_.'msPKI-Cert-Template-OID' -eq $Matches.Oid
                })

                $Matches['DisplayName'] = $template.DisplayName
            }
            else
            {
                $template = $adTemplates.Where({
                    $_.'DisplayName' -eq $Matches.DisplayName
                })
            }

            $Matches['Name'] = $template.Name

            if ($template.Count -eq 0)
            {
                Write-Warning -Message ($LocalizedData.TemplateNameResolutionError -f ('{0}({1})' -f $Matches.DisplayName, $Matches.Oid))
            }

            $templateInformation['Name']         = $Matches.Name
            $templateInformation['DisplayName']  = $Matches.DisplayName
            $templateInformation['Oid']          = $Matches.Oid
            $templateInformation['MajorVersion'] = $Matches.MajorVersion
            $templateInformation['MinorVersion'] = $Matches.MinorVersion
        }

        # The certificate extension template text just contains the name of the template so return that.

        '^(?<TemplateName>\w+)\s?$'
        {
            $templateInformation['Name'] = $Matches.TemplateName
        }

        default
        {
            Write-Warning -Message ($LocalizedData.TemplateNameNotFound -f $FormattedTemplate)
        }
    }

    return [PSCustomObject] $templateInformation
}

<#
    .SYNOPSIS
    Returns one or more matching extensions matching the requested Oid.
 
    .DESCRIPTION
    This function finds all extensions matching one of the specified Oid values
    and returns one or more of them.
 
    .PARAMETER Certificate
    The X509 certificate to return the extensions from.
 
    .PARAMETER Oid
    The list of Oid's to extract extensions from.
 
    .PARAMETER First
    The number of matching extensions to return.
#>

function Get-CertificateExtension
{
    [CmdletBinding()]
    [OutputType([System.Security.Cryptography.X509Certificates.X509Extension[]])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Object]
        $Certificate,

        [Parameter(Mandatory = $true)]
        [System.String[]]
        $Oid,

        [Parameter()]
        [System.Int32]
        $First = 1
    )

    $extensions = $certificate.Extensions | Where-Object -FilterScript {
        $_.Oid.value -in $Oid
    } | Select-Object -First $First

    return $extensions
}

<#
    .SYNOPSIS
    Gets the formatted text output from an X509 certificate template extension.
 
    .DESCRIPTION
    Looks up the extensions with either the Oid "1.3.6.1.4.1.311.21.7" or
    "1.3.6.1.4.1.311.20.2" and returns the formatted extension value.
 
    .PARAMETER Certificate
    The x509 certificate to return the template extension from.
#>

function Get-CertificateTemplateExtensionText
{
    [CmdletBinding()]
    [OutputType([System.String])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Security.Cryptography.X509Certificates.X509Certificate2]
        $Certificate
    )

    $templateOidNames = '1.3.6.1.4.1.311.21.7', '1.3.6.1.4.1.311.20.2'
    $firstTemplateExtension = Get-CertificateExtension @PSBoundParameters `
        -Oid $templateOidNames

    if ($null -ne $firstTemplateExtension)
    {
        return $firstTemplateExtension.Format($true)
    }
}

<#
    .SYNOPSIS
    Get a certificate template name from an x509 certificate.
 
    .DESCRIPTION
    Gets the name of the template used for the certificate that is passed to
    this cmdlet by translating the OIDs "1.3.6.1.4.1.311.21.7" or
    "1.3.6.1.4.1.311.20.2".
 
    .PARAMETER Certificate
    The x509 certificate to return the formatted template extension from.
#>

function Get-CertificateTemplateName
{
    [cmdletBinding()]
    [OutputType([System.String])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Object]
        $Certificate
    )

    if ($Certificate -isnot [System.Security.Cryptography.X509Certificates.X509Certificate2])
    {
        return
    }

    $templateExtensionText = Get-CertificateTemplateExtensionText @PSBoundParameters

    if ($null -ne $templateExtensionText)
    {
        return Get-CertificateTemplateInformation -FormattedTemplate $templateExtensionText |
            Select-Object -ExpandProperty Name
    }
}

<#
    .SYNOPSIS
    Get the first Subject Alternative Name entry for a certificate.
 
    .DESCRIPTION
    Gets the first entry in the Subject Alternative Name extension from the
    certificate provided.
 
    .PARAMETER Certificate
    The certificate to return the Subject Alternative Name from.
#>

function Get-CertificateSubjectAlternativeName
{
    [cmdletBinding()]
    [OutputType([System.String])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Object]
        $Certificate
    )

    if ($Certificate -isnot [System.Security.Cryptography.X509Certificates.X509Certificate2])
    {
        return
    }

    $list = Get-CertificateSubjectAlternativeNameList -Certificate $Certificate

    if ($null -ne $list)
    {
        $firstSubjectAlternativeName = Get-CertificateSubjectAlternativeNameList -Certificate $Certificate |
            Select-Object -First 1

        return $firstSubjectAlternativeName.Split('=')[1]
    }
}

<#
    .SYNOPSIS
    Get the list of Subject Alternative Name entries in a Certificate.
 
    .DESCRIPTION
    Gets the list of Subject Alternative Name entries in the extension
    with Oid 2.5.29.17 from the certificate provided.
 
    .PARAMETER Certificate
    The certificate to return the Subject Alternative Name entry list from.
#>

function Get-CertificateSubjectAlternativeNameList
{
    [cmdletBinding()]
    [OutputType([System.String[]])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Object]
        $Certificate
    )

    $subjectAlternateNameExtensions = Get-CertificateExtension -Certificate $Certificate -Oid '2.5.29.17'
    $subjectAlternateNames = @()

    if ($null -ne $subjectAlternateNameExtensions)
    {
        $subjectAlternateNames = ($subjectAlternateNameExtensions.Format($false) -split ',').Trim()
    }

    return $subjectAlternateNames
}

<#
    .SYNOPSIS
    Tests whether or not the command with the specified name exists.
 
    .PARAMETER Name
    The name of the command to test for.
#>

function Test-CommandExists
{
    [OutputType([System.Boolean])]
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true)]
        [ValidateNotNullOrEmpty()]
        [System.String]
        $Name
    )

    $command = Get-Command -Name $Name -ErrorAction 'SilentlyContinue'
    return ($null -ne $command)
}

<#
    .SYNOPSIS
    This function imports a 509 public key certificate to the specific Store.
 
    .PARAMETER FilePath
    The path to the certificate file to import.
 
    .PARAMETER CertStoreLocation
    The Certificate Store and Location Path to import the certificate to.
#>

function Import-CertificateEx
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $FilePath,

        [Parameter(Mandatory = $true)]
        [System.String]
        $CertStoreLocation
    )

    $location = Split-Path -Path (Split-Path -Path $CertStoreLocation -Parent) -Leaf
    $store = Split-Path -Path $CertStoreLocation -Leaf

    $cert = New-Object -TypeName System.Security.Cryptography.X509Certificates.X509Certificate2Collection
    $cert.Import($FilePath)

    $certStore = New-Object `
        -TypeName System.Security.Cryptography.X509Certificates.X509Store `
        -ArgumentList ($store, $location)

    $certStore.Open('MaxAllowed')
    $certStore.AddRange($cert)
    $certStore.Close()
}

<#
    .SYNOPSIS
    This function imports a Pfx public - private certificate to the specific
    Certificate Store Location.
 
    .PARAMETER FilePath
    The path to the certificate file to import.
 
    .PARAMETER CertStoreLocation
    The Certificate Store and Location Path to import the certificate to.
 
    .PARAMETER Exportable
    The parameter controls if certificate will be able to export the private key.
 
    .PARAMETER Password
    The password that the certificate located at the FilePath needs to be imported.
  #>

function Import-PfxCertificateEx
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $FilePath,

        [Parameter(Mandatory = $true)]
        [System.String]
        $CertStoreLocation,

        [Parameter()]
        [Switch]
        $Exportable,

        [Parameter()]
        [System.Security.SecureString]
        $Password
    )

    $location = Split-Path -Path (Split-Path -Path $CertStoreLocation -Parent) -Leaf
    $store = Split-Path -Path $CertStoreLocation -Leaf

    $cert = New-Object -TypeName System.Security.Cryptography.X509Certificates.X509Certificate2

    $flags = [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::PersistKeySet

    if ($Exportable)
    {
        $flags = $flags -bor [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::Exportable
    }

    if ($Password)
    {
        $cert.Import($FilePath, $Password, $flags)
    }
    else
    {
        $cert.Import($FilePath, $flags)
    }

    $certStore = New-Object `
        -TypeName System.Security.Cryptography.X509Certificates.X509Store `
        -ArgumentList @($store, $location)

    $certStore.Open('MaxAllowed')
    $certStore.Add($cert)
    $certStore.Close()
}

<#
    .SYNOPSIS
    This function generates the path to a Windows Certificate Store.
 
    .PARAMETER Location
    The Windows Certificate Store Location.
 
    .PARAMETER Store
    The Windows Certificate Store Name.
#>

function Get-CertificateStorePath
{
    [CmdletBinding()]
    [OutputType([System.String])]
    param
    (
        [Parameter(Mandatory = $true)]
        [ValidateSet('CurrentUser', 'LocalMachine')]
        [System.String]
        $Location,

        [Parameter(Mandatory = $true)]
        [ValidateNotNullOrEmpty()]
        [System.String]
        $Store
    )

    return 'Cert:' |
        Join-Path -ChildPath $Location |
        Join-Path -ChildPath $Store
}