(CkPython) 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.

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.

# Load a JPG file that will be the JWE payload.
jpgBytes = chilkat.CkBinData()
success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")
# Make sure your app checks the success/failure of the call to LoadFile..
print("Original JPG size = " + str(jpgBytes.get_NumBytes()))

jwe = chilkat.CkJwe()

jweProtHdr = chilkat.CkJsonObject()
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 = chilkat.CkStringBuilder()
success = jwe.EncryptBd(jpgBytes,sbJwe)
if (success != True):
    print(jwe.lastErrorText())
    sys.exit()

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

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

jwe2 = chilkat.CkJwe()
success = jwe2.LoadJweSb(sbJwe)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

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

# Decrypt.
jpgOriginal = chilkat.CkBinData()
success = jwe2.DecryptBd(0,jpgOriginal)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

print("Decrypted JPG size = " + str(jpgOriginal.get_NumBytes()))

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

print("success = " + str(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