(PowerShell) JWS Using HMAC SHA-256

Creates a JSON Web Signatures (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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

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

# Note: This example requires Chilkat v9.5.0.66 or greater.

# First create the JWS Protected Header
$jwsProtHdr = New-Object Chilkat.JsonObject
$jwsProtHdr.AppendString("typ","JWT")
$jwsProtHdr.AppendString("alg","HS256")
$("JWS Protected Header: " + $jwsProtHdr.Emit())

# Output:
# JWS Protected Header: {"typ":"JWT","alg":"HS256"}

$jws = New-Object Chilkat.Jws

# Set the HMAC key:
$hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
$signatureIndex = 0
$jws.SetMacKey($signatureIndex,$hmacKey,"base64url")

# Set the protected header:
$jws.SetProtectedHeader($signatureIndex,$jwsProtHdr)

# Set the payload.
$bIncludeBom = $false
$payloadStr = "In our village, folks say God crumbles up the old moon into stars."
$jws.SetPayload($payloadStr,"utf-8",$bIncludeBom)

# Create the JWS
# By default, the compact serialization is used.
$jwsCompact = $jws.CreateJws()
if ($jws.LastMethodSuccess -ne $true) {
    $($jws.LastErrorText)
    exit
}

$("JWS: " + $jwsCompact)

# sample output:
# JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

# Now load the JWS, validate, and recover the original text.
$jws2 = New-Object Chilkat.Jws

# Load the JWS.
$success = $jws2.LoadJws($jwsCompact)

# Set the MAC key used for validation.
$signatureIndex = 0
$jws2.SetMacKey($signatureIndex,$hmacKey,"base64url")

# Validate the 1st (and only) signature at index 0..
$v = $jws2.Validate($signatureIndex)
if ($v -lt 0) {
    # Perhaps Chilkat was not unlocked or the trial expired..
    $("Method call failed for some other reason.")
    $($jws2.LastErrorText)
    exit
}

if ($v -eq 0) {
    $("Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.")
    exit
}

# If we get here, the signature was validated..
$("Signature validated.")

# Recover the original content:
$($jws2.GetPayload("utf-8"))

# Examine the protected header:
$joseHeader = $jws2.GetProtectedHeader($signatureIndex)
if ($jws2.LastMethodSuccess -ne $true) {
    $("No protected header found at the given index.")
    exit
}

$joseHeader.EmitCompact = $false

$("Protected (JOSE) header:")
$($joseHeader.Emit())

# Output:

# 	Signature validated.
# 	In our village, folks say God crumbles up the old moon into stars.
# 	Protected (JOSE) header:
# 	{ 
# 	  "typ": "JWT",
# 	  "alg": "HS256"
# 	}