(PowerShell) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Note: This example requires Chilkat v11.0.0 or greater.

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

$success = $false

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

# Load the certificate from a smart card.
$cert = New-Object Chilkat.Cert
$success = $cert.LoadFromSmartcard("")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

# Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
# such as selecting a certificate if the card contains multiple certificates with private keys,
# or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

# If the associated private key was present on the smartcard, then you can simply
# get it from the Chilkat cert object:
$privKey = New-Object Chilkat.PrivateKey
$success = $cert.GetPrivateKey($privKey)
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

# You can check the key type to make sure it's RSA.
# This will output "rsa" if the key is RSA.
$("Key type = " + $privKey.KeyType)

# Create the JWS Protected Header
$jwsProtHdr = New-Object Chilkat.JsonObject
$jwsProtHdr.AppendString("alg","RS256")

$jws = New-Object Chilkat.Jws

# Set the protected header:
$signatureIndex = 0
$jws.SetProtectedHeader($signatureIndex,$jwsProtHdr)

# Set the RSA key:
$jws.SetPrivateKey($signatureIndex,$privKey)

# 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 -eq $false) {
    $($jws.LastErrorText)
    exit
}

$("JWS: " + $jwsCompact)

# sample output:
# JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

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

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

$rsaPubKey = New-Object Chilkat.PublicKey
$privKey.ToPublicKey($rsaPubKey)

# Set the RSA public key used for validation.
$signatureIndex = 0
$jws2.SetPublicKey($signatureIndex,$rsaPubKey)

# 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 RSA 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 = New-Object Chilkat.JsonObject
$success = $jws2.GetProtectedH($signatureIndex,$joseHeader)
if ($success -eq $false) {
    $($jws2.LastErrorText)
    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:
# 	{ 
# 	  "alg": "RS256"
# 	}