(PowerShell) Adyen HMAC Signature Calculation for Hosted Payment Pages

Demonstrates how to do the HMAC Signature Calculation for a hosted payment page (HPP) in Adyen.

For a C# ASP.NET Razor Pages example showing the HTML Form with HMAC signature code, see Adyen HMAC Signature Calculation in C#

For more information, see https://docs.adyen.com/classic-integration/hosted-payment-pages/hmac-signature-calculation/

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$strHtml = "<table class=`"od`"><tr><th>Description</th><th>Quantity</th><th>Amount</th></tr><tr><td>1 Digital Camera</td><td class=`"r`">1</td><td class=`"r`">100 GBP</td></tr><tr><td class=`"b`">Total</td><td class=`"r`"></td><td class=`"b r`">100.00 GBP</td></tr></table>"

$gzip = New-Object Chilkat.Gzip
$gzOrderData = $gzip.CompressStringENC($strHtml,"utf-8","base64")

$xml = New-Object Chilkat.Xml
$xml.Tag = "keyValuePairs"

$xml.NewChild2("orderData",$gzOrderData)

# required, The payment deadline; the payment needs to occur within the specified time value.
$sessionValidity = "2019-08-11T10:30:00Z"
$xml.NewChild2("sessionValidity",$sessionValidity)

# optional.  Normally we'll let Adyen automatically know the country based on the IP address.
# By default, the payment methods offered to a shopper are filtered based on the country the shopper's IP address is mapped to. 
# In this way, shoppers are not offered payment methods that are not available in the country they are carrying out the transaction from. 
# This IP-to-country mapping is not 100% accurate, so if you have already established the country of the shopper, you can set it explicitly 
# in the countryCode parameter.
$countryCode = "GB"
$xml.NewChild2("countryCode",$countryCode)

# optional
$shopperLocale = "en_GB"
# If not specified, the locale preference is set to en_GB   by default.
# When it is not necessary to include the country-specific part, use only the language code.
# For example: it instead of it_IT to set the locale preferences to Italian.
$xml.NewChild2("shopperLocale",$shopperLocale)

# required, A reference to uniquely identify the payment. This reference is used in all communication with you about the payment status. 
# We recommend using a unique value per payment; however, it is not a requirement. If you need to provide multiple references for a transaction, 
# you can enter them in this field. Separate each reference value with a hyphen character ("-"). This field has a length restriction: 
# you can enter max. 80 characters.
$merchantReference = "paymentTest1234"
$xml.NewChild2("merchantReference",$merchantReference)

# required, The merchant account identifier you want to process the (transaction) request with.
$merchantAccount = "ChilkatSoftwareIncCOM"
$xml.NewChild2("merchantAccount",$merchantAccount)

# required.  10000 for $100.00
$paymentAmount = "10000"
$xml.NewChild2("paymentAmount",$paymentAmount)

# required, The three-character ISO currency code
$currencyCode = "GBP"
$xml.NewChild2("currencyCode",$currencyCode)

# required.
$skinCode = "S7uWsvfB"
$xml.NewChild2("skinCode",$skinCode)

# optional, A unique identifier for the shopper, for example, a customer ID.
# We recommend providing this information, as it is used in velocity fraud checks. It is also the key in recurring payments.
# This field is mandatory in recurring payments.  
$shopperReference = "somebody@example.com"
$xml.NewChild2("shopperReference",$shopperReference)

# optional
$shopperEmail = "somebody@example.com"
$xml.NewChild2("shopperEmail",$shopperEmail)

# optional, An integer value that adds up to the normal fraud score.
# The value can be either a positive or negative integer.
$xml.NewChild2("offset","0")

# Apparently this is a required field.
$shipBeforeDate = "2019-06-04"
$xml.NewChild2("shipBeforeDate",$shipBeforeDate)

$xml.SortByTag($true)

# Encode...
#  "\" (backslash) as "\\"
#  ":" (colon) as "\:"

$sbTags = New-Object Chilkat.StringBuilder
$sbValues = New-Object Chilkat.StringBuilder

$sbContent = New-Object Chilkat.StringBuilder
$n = $xml.NumChildren
$i = 0
while ($i -lt $n) {
    if ($i -gt 0) {
        $sbTags.Append(":")
        $sbValues.Append(":")
    }

    $xml.GetChild2($i)
    $sbTags.Append($xml.Tag)

    $sbContent.SetString($xml.Content)
    $numReplaced = $sbContent.Replace("\`","\\\`")
    $numReplaced = $sbContent.Replace(":","\\:")
    $sbValues.AppendSb($sbContent)
    $xml.GetParent2()

    $i = $i + 1
}

$sbSigningStr = New-Object Chilkat.StringBuilder
$sbSigningStr.AppendSb($sbTags)
$sbSigningStr.Append(":")
$sbSigningStr.AppendSb($sbValues)

$crypt = New-Object Chilkat.Crypt2
$crypt.HashAlgorithm = "sha256"
$crypt.MacAlgorithm = "hmac"

$hmacKey = "934D1E806DDD99595EB430076FD7F8E4D12D0A3F51243A4C0C3897703118E739"
$crypt.SetMacKeyEncoded($hmacKey,"hex")

$crypt.EncodingMode = "base64"
$merchantSig = $crypt.HmacStringENC($sbSigningStr.GetAsString())

$($merchantSig)