PowerShell

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

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

PowerShell

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.

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

$plaintext = "Live long and prosper."

$jwe = New-Object Chilkat.Jwe

# First build the JWE Protected Header..
$jweProtHdr = New-Object Chilkat.JsonObject
$jweProtHdr.AppendString("alg","dir")
$jweProtHdr.AppendString("enc","A128GCM")

# Don't forget to actually provide the protected header to the JWE object:
$jwe.SetProtectedHeader($jweProtHdr)

# The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
# Given that the "alg" = "dir", we are to directly specify the AES GCM key.
# (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

# Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

# The SetWrappingKey method is also used for "dir" direct keys.
# However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
# which is specified by calling SetWrappingKey with an index of 0.

$recipientIndex = 0
$jwe.SetWrappingKey($recipientIndex,"000102030405060708090A0B0C0D0E0F","hex")

# Encrypt and return the JWE:
$strJwe = $jwe.Encrypt($plaintext,"utf-8")
if ($jwe.LastMethodSuccess -ne $true) {
    $($jwe.LastErrorText)
    exit
}

# Show the JWE we just created:
$($strJwe)

# Decrypt the JWE.
$jwe2 = New-Object Chilkat.Jwe
$success = $jwe2.LoadJwe($strJwe)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex")

# Decrypt.
$originalPlaintext = $jwe2.Decrypt(0,"utf-8")
if ($jwe2.LastMethodSuccess -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$("original text: ")
$($originalPlaintext)

# Sample output:
# eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
# original text: 
# Live long and prosper.