(CkPython) JWE with DEFLATE Compression

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

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

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux, Solaris

import sys
import chilkat

# 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 = chilkat.CkStringBuilder()
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:
print(sbPlainText.getAsString())

jwe = chilkat.CkJwe()

# 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 = chilkat.CkJsonObject()
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 = chilkat.CkStringBuilder()
success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweCompressed)
if (success != True):
    print(jwe.lastErrorText())
    sys.exit()

# Show the compressed JWE:
print(sbJweCompressed.getAsString())
print("size of compressed JWE: " + str(sbJweCompressed.get_Length()))

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

sbJweUncompressed = chilkat.CkStringBuilder()
success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweUncompressed)
if (success != True):
    print(jwe.lastErrorText())
    sys.exit()

# Show the uncompressed JWE:
print(sbJweUncompressed.getAsString())
print("size of uncompressed JWE: " + str(sbJweUncompressed.get_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 = chilkat.CkJwe()
success = jwe2.LoadJweSb(sbJweCompressed)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

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

# Decrypt (also automatically decompresses).
sbOriginalText = chilkat.CkStringBuilder()
success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

print("original text from compressed JWE: ")
print(sbOriginalText.getAsString())

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

success = jwe2.LoadJweSb(sbJweUncompressed)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

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

# Decrypt.
sbOriginalText.Clear()
success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

print("original text from uncompressed JWE: ")
print(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.
#