(Chilkat2-Python) JWE using RSAES-PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256

This example duplicates the example A.2 in RFC 7516 for JSON Web Encryption (JWE).

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

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS, Solaris

import sys
import chilkat2

# 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."

# First build the JWE Protected Header.
# We want to build this: {"alg":"RSA1_5","enc":"A128CBC-HS256"}
jweProtHdr = chilkat2.JsonObject()
jweProtHdr.AppendString("alg","RSA1_5")
jweProtHdr.AppendString("enc","A128CBC-HS256")
print("JWE Protected Header: " + jweProtHdr.Emit())
print("--")

# The specific RSA key used in the A.2 example is the following JWK:
sbJwk = chilkat2.StringBuilder()
sbJwk.Append("{\"kty\":\"RSA\",")
sbJwk.Append("\"n\":\"sXchDaQebHnPiGvyDOAT4saGEUetSyo9MKLOoWFsueri23bOdgWp4Dy1Wl")
sbJwk.Append("UzewbgBHod5pcM9H95GQRV3JDXboIRROSBigeC5yjU1hGzHHyXss8UDpre")
sbJwk.Append("cbAYxknTcQkhslANGRUZmdTOQ5qTRsLAt6BTYuyvVRdhS8exSZEy_c4gs_")
sbJwk.Append("7svlJJQ4H9_NxsiIoLwAEk7-Q3UXERGYw_75IDrGA84-lA_-Ct4eTlXHBI")
sbJwk.Append("Y2EaV7t7LjJaynVJCpkv4LKjTTAumiGUIuQhrNhZLuF_RJLqHpM2kgWFLU")
sbJwk.Append("7-VTdL1VbC2tejvcI2BlMkEpk1BzBZI0KQB0GaDWFLN-aEAw3vRw\",")
sbJwk.Append("\"e\":\"AQAB\",")
sbJwk.Append("\"d\":\"VFCWOqXr8nvZNyaaJLXdnNPXZKRaWCjkU5Q2egQQpTBMwhprMzWzpR8Sxq")
sbJwk.Append("1OPThh_J6MUD8Z35wky9b8eEO0pwNS8xlh1lOFRRBoNqDIKVOku0aZb-ry")
sbJwk.Append("nq8cxjDTLZQ6Fz7jSjR1Klop-YKaUHc9GsEofQqYruPhzSA-QgajZGPbE_")
sbJwk.Append("0ZaVDJHfyd7UUBUKunFMScbflYAAOYJqVIVwaYR5zWEEceUjNnTNo_CVSj")
sbJwk.Append("-VvXLO5VZfCUAVLgW4dpf1SrtZjSt34YLsRarSb127reG_DUwg9Ch-Kyvj")
sbJwk.Append("T1SkHgUWRVGcyly7uvVGRSDwsXypdrNinPA4jlhoNdizK2zF2CWQ\",")
sbJwk.Append("\"p\":\"9gY2w6I6S6L0juEKsbeDAwpd9WMfgqFoeA9vEyEUuk4kLwBKcoe1x4HG68")
sbJwk.Append("ik918hdDSE9vDQSccA3xXHOAFOPJ8R9EeIAbTi1VwBYnbTp87X-xcPWlEP")
sbJwk.Append("krdoUKW60tgs1aNd_Nnc9LEVVPMS390zbFxt8TN_biaBgelNgbC95sM\",")
sbJwk.Append("\"q\":\"uKlCKvKv_ZJMVcdIs5vVSU_6cPtYI1ljWytExV_skstvRSNi9r66jdd9-y")
sbJwk.Append("BhVfuG4shsp2j7rGnIio901RBeHo6TPKWVVykPu1iYhQXw1jIABfw-MVsN")
sbJwk.Append("-3bQ76WLdt2SDxsHs7q7zPyUyHXmps7ycZ5c72wGkUwNOjYelmkiNS0\",")
sbJwk.Append("\"dp\":\"w0kZbV63cVRvVX6yk3C8cMxo2qCM4Y8nsq1lmMSYhG4EcL6FWbX5h9yuv")
sbJwk.Append("ngs4iLEFk6eALoUS4vIWEwcL4txw9LsWH_zKI-hwoReoP77cOdSL4AVcra")
sbJwk.Append("Hawlkpyd2TWjE5evgbhWtOxnZee3cXJBkAi64Ik6jZxbvk-RR3pEhnCs\",")
sbJwk.Append("\"dq\":\"o_8V14SezckO6CNLKs_btPdFiO9_kC1DsuUTd2LAfIIVeMZ7jn1Gus_Ff")
sbJwk.Append("7B7IVx3p5KuBGOVF8L-qifLb6nQnLysgHDh132NDioZkhH7mI7hPG-PYE_")
sbJwk.Append("odApKdnqECHWw0J-F0JWnUd6D2B_1TvF9mXA2Qx-iGYn8OVV1Bsmp6qU\",")
sbJwk.Append("\"qi\":\"eNho5yRBEBxhGBtQRww9QirZsB66TrfFReG_CcteI1aCneT0ELGhYlRlC")
sbJwk.Append("tUkTRclIfuEPmNsNDPbLoLqqCVznFbvdB7x-Tl-m0l_eFTj2KiqwGqE9PZ")
sbJwk.Append("B9nNTwMVvH3VRRSLWACvPnSiwP8N5Usy-WRXS-V7TbpxIhvepTfE0NNo\"")
sbJwk.Append("}")

# Load this JWK into a Chilkat private key object.
rsaPrivKey = chilkat2.PrivateKey()
success = rsaPrivKey.LoadJwk(sbJwk.GetAsString())
if (success != True):
    print(rsaPrivKey.LastErrorText)
    sys.exit()

# The public key is used to encrypt (i.e. create the JWE), 
# and the private key is used to decrypt.
# The RSA public key is simply a subset of the private key.  The RSA public key
# is composed of the "n" and "e" members shown above.  These are also known as the
# modulus and exponent.
# We can simply get the public key object from the private key object
# rsaPubKey is a CkPublicKey
rsaPubKey = rsaPrivKey.GetPublicKey()

# Create the JWE...
jwe = chilkat2.Jwe()
jwe.SetProtectedHeader(jweProtHdr)
jwe.SetPublicKey(0,rsaPubKey)

strJwe = jwe.Encrypt(plaintext,"utf-8")
if (jwe.LastMethodSuccess != True):
    print(jwe.LastErrorText)
    sys.exit()

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

# Note: The RSA PKCS1_V1_5 padding uses random value, and the results
# will be different each time.  However, each result should be successfully
# decrypting if using the correct RSA private key.

# Let's decrypt the JWE that was just produced.
# Do the following to decrypt a JWE:
# 1) Load the JWE.
# 2) Set the private key for decryption.
# 3) Decrypt.
jwe2 = chilkat2.Jwe()
success = jwe2.LoadJwe(strJwe)
if (success != True):
    print(jwe2.LastErrorText)
    sys.exit()

# Provide the RSA private key for decryption.
# (The JWE was encrypted for a single recipient at index 0.)
jwe2.SetPrivateKey(0,rsaPrivKey)

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

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

# ---------------------------------------------------------------------------------
# It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.2.7
# because it was produced using the same RSA key.

sbJwe = chilkat2.StringBuilder()
sbJwe.Append("eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.")
sbJwe.Append("UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm")
sbJwe.Append("1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc")
sbJwe.Append("HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF")
sbJwe.Append("NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8")
sbJwe.Append("rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv")
sbJwe.Append("-B3oWh2TbqmScqXMR4gp_A.")
sbJwe.Append("AxY8DCtDaGlsbGljb3RoZQ.")
sbJwe.Append("KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.")
sbJwe.Append("9hH0vgRfYgPnAHOd8stkvw")

success = jwe2.LoadJweSb(sbJwe)
if (success != True):
    print(jwe2.LastErrorText)
    sys.exit()

# Provide the RSA private key for decryption.
jwe2.SetPrivateKey(0,rsaPrivKey)

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

print(originalPlaintext)