CkPython

JWE with Binary Data

See more JSON Web Encryption (JWE) Examples

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.

CkPython

import sys
import chilkat

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.

# 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