PowerShell

JWE with DEFLATE Compression

See more JSON Web Encryption (JWE) Examples

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

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.

# Create some plaintext to be encrypted.
# This example will demonstrate with and without DEFLATE (zip) compression.
$sbPlainText = New-Object Chilkat.StringBuilder
$bCrLf = $true
$line = "Live long and prosper."
$sbPlainText.AppendLine($line,$bCrLf)
$sbPlainText.AppendLine($line,$bCrLf)
$sbPlainText.AppendLine($line,$bCrLf)
$sbPlainText.AppendLine($line,$bCrLf)

# The text to be encrypted:
$($sbPlainText.GetAsString())

$jwe = New-Object Chilkat.Jwe

# Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
# The "zip":"DEF" parameter indicates that the plaintext payload should
# be compressed prior to encryption.
$jweProtHdr = New-Object Chilkat.JsonObject
$jweProtHdr.AppendString("alg","A128KW")
$jweProtHdr.AppendString("enc","A128CBC-HS256")
$jweProtHdr.AppendString("zip","DEF")
$jwe.SetProtectedHeader($jweProtHdr)

# Set the AES key wrap key:
$aesWrappingKey = "GawgguFyGrWKav7AX4VKUg"
$jwe.SetWrappingKey(0,$aesWrappingKey,"base64url")

# Encrypt and return the JWE in sbJweCompressed:
$sbJweCompressed = New-Object Chilkat.StringBuilder
$success = $jwe.EncryptSb($sbPlainText,"utf-8",$sbJweCompressed)
if ($success -ne $true) {
    $($jwe.LastErrorText)
    exit
}

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

# Now create a JWE without compression.
$jweProtHdr.Delete("zip")
# Make sure to update the shared protected header:
$jwe.SetProtectedHeader($jweProtHdr)

$sbJweUncompressed = New-Object Chilkat.StringBuilder
$success = $jwe.EncryptSb($sbPlainText,"utf-8",$sbJweUncompressed)
if ($success -ne $true) {
    $($jwe.LastErrorText)
    exit
}

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

# Decrypting is the same whether compression is used or not.
# The "zip" header in the JWE indicates that the payload should be 
# automatically decompressed (inflated) after decrypting.
$jwe2 = New-Object Chilkat.Jwe
$success = $jwe2.LoadJweSb($sbJweCompressed)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

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

# Decrypt (also automatically decompresses).
$sbOriginalText = New-Object Chilkat.StringBuilder
$success = $jwe2.DecryptSb(0,"utf-8",$sbOriginalText)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$("original text from compressed JWE: ")
$($sbOriginalText.GetAsString())

# -----------------------------------------------------------
# Do the same with the uncompressed JWE

$success = $jwe2.LoadJweSb($sbJweUncompressed)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

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

# Decrypt.
$sbOriginalText.Clear()
$success = $jwe2.DecryptSb(0,"utf-8",$sbOriginalText)
if ($success -ne $true) {
    $($jwe2.LastErrorText)
    exit
}

$("original text from uncompressed JWE: ")
$($sbOriginalText.GetAsString())

# ------------------------------------------------
# The output of this example is:
# (Note: Your output data will be different because the content encryption key is randomly generated.)

# eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
# size of compressed JWE: 212
# eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
# size of uncompressed JWE: 303
# original text from compressed JWE: 
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# 
# original text from uncompressed JWE: 
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
# Live long and prosper.
#