(PowerShell) JWE with Binary Data

Demonstrates how to create a JWE that contains a binary payload (such as a JPG image).

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.

# Load a JPG file that will be the JWE payload.
$jpgBytes = New-Object Chilkat.BinData
$success = $jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")
# Make sure your app checks the success/failure of the call to LoadFile..
$("Original JPG size = " + $jpgBytes.NumBytes)

$jwe = New-Object Chilkat.Jwe

$jweProtHdr = New-Object Chilkat.JsonObject
$jweProtHdr.AppendString("alg","A128KW")
$jweProtHdr.AppendString("enc","A128CBC-HS256")
$jwe.SetProtectedHeader($jweProtHdr)

$aesWrappingKey = "GawgguFyGrWKav7AX4VKUg"
$jwe.SetWrappingKey(0,$aesWrappingKey,"base64url")

# Encrypt and return the JWE in sbJwe:
$sbJwe = New-Object Chilkat.StringBuilder
$success = $jwe.EncryptBd($jpgBytes,$sbJwe)
if ($success -ne $true) {
    $($jwe.LastErrorText)
    exit
}

# Show the JWE:
$($sbJwe.GetAsString())
$("size of JWE: " + $sbJwe.Length)

# ---------------------------------------------------------
# Decrypt to get the original JPG file..

$jwe2 = New-Object Chilkat.Jwe
$success = $jwe2.LoadJweSb($sbJwe)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

# Set the AES wrap key.
$jwe2.SetWrappingKey(0,$aesWrappingKey,"base64url")

# Decrypt.
$jpgOriginal = New-Object Chilkat.BinData
$success = $jwe2.DecryptBd(0,$jpgOriginal)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$("Decrypted JPG size = " + $jpgOriginal.NumBytes)

# Save the decrypted JPG to a file.
$success = $jpgOriginal.WriteFile("qa_output/jwe_decrypted_starfish.jpg")

$("success = " + $success)

# The output of this program, when tested, was:
# Original JPG size = 6229
# eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.9YFz_wteV ... 7Et3hKhpxnKEXw
# size of JWE: 8473
# Decrypted JPG size = 6229
# success = True