(CkPython) JWE using "dir" Direct use of Shared Symmetric Key

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

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.

plaintext = "Live long and prosper."

jwe = chilkat.CkJwe()

# First build the JWE Protected Header..
jweProtHdr = chilkat.CkJsonObject()
jweProtHdr.AppendString("alg","dir")
jweProtHdr.AppendString("enc","A128GCM")

# Don't forget to actually provide the protected header to the JWE object:
jwe.SetProtectedHeader(jweProtHdr)

# The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
# Given that the "alg" = "dir", we are to directly specify the AES GCM key.
# (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

# Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

# The SetWrappingKey method is also used for "dir" direct keys.
# However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
# which is specified by calling SetWrappingKey with an index of 0.

recipientIndex = 0
jwe.SetWrappingKey(recipientIndex,"000102030405060708090A0B0C0D0E0F","hex")

# Encrypt and return the JWE:
strJwe = jwe.encrypt(plaintext,"utf-8")
if (jwe.get_LastMethodSuccess() != True):
    print(jwe.lastErrorText())
    sys.exit()

# Show the JWE we just created:
print(strJwe)

# Decrypt the JWE.
jwe2 = chilkat.CkJwe()
success = jwe2.LoadJwe(strJwe)
if (success != True):
    print(jwe2.lastErrorText())
    sys.exit()

jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex")

# Decrypt.
originalPlaintext = jwe2.decrypt(0,"utf-8")
if (jwe2.get_LastMethodSuccess() != True):
    print(jwe2.lastErrorText())
    sys.exit()

print("original text: ")
print(originalPlaintext)

# Sample output:
# eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
# original text: 
# Live long and prosper.