(CkPython) Verify a JWT Created by the Amazon Cognito Service

Demonstrates how to verify a JWT created by the Amazon Cognito Service.

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 example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# The public keys for this example are at https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json
# Let's get them:

http = chilkat.CkHttp()
sbJsonKeys = chilkat.CkStringBuilder()
success = http.QuickGetSb("https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json",sbJsonKeys)
if (success == False):
    print(http.lastErrorText())
    sys.exit()

jsonKeys = chilkat.CkJsonObject()
jsonKeys.LoadSb(sbJsonKeys)
jsonKeys.put_EmitCompact(False)
print(jsonKeys.emit())

# Here are the keys:

# {
#   "keys": [
#     {
#       "alg": "RS256",
#       "e": "AQAB",
#       "kid": "1A/L5Fsb2EsEwxy5E0cmCMS1BnMe6Jl6NXiMig4iNwU=",
#       "kty": "RSA",
#       "n": "y0w7BJrIJYi ... jKG27z2P3OKw",
#       "use": "sig"
#     },
#     {
#       "alg": "RS256",
#       "e": "AQAB",
#       "kid": "mos6VTJnvDwurY3ghJg6IAPUq+dMwl6CL/iThzJOkzg=",
#       "kty": "RSA",
#       "n": "qbIEH-7tg6yrT ... 3Fj94ooTd0w",
#       "use": "sig"
#     }
#   ]
# }

# Try the 1st key.
# jsonKey1 is a CkJsonObject
jsonKey1 = jsonKeys.ObjectOf("keys[0]")
if (jsonKeys.get_LastMethodSuccess() == False):
    print("Did not get the 1st JSON public key.")
    sys.exit()

pubKey1 = chilkat.CkPublicKey()
success = pubKey1.LoadFromString(jsonKey1.emit())
if (success == False):
    print(pubKey1.lastErrorText())
    sys.exit()

print("Success")

jwt = chilkat.CkJwt()

# I did not include the an actual AWS Cognito token here because our test sample used customer-provided data..
token = "eyJ..asXg"

# First verify the signature.
sigVerified = jwt.VerifyJwtPk(token,pubKey1)
print("verified: " + str(sigVerified))

# Let's see if the time constraints, if any, are valid.
# The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
# If the current system time is before the "nbf" time, or after the "exp" time,
# then IsTimeValid will return false/0.
# Also, we'll allow a leeway of 60 seconds to account for any clock skew.
# Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
leeway = 60
bTimeValid = jwt.IsTimeValid(token,leeway)
print("time constraints valid: " + str(bTimeValid))

# Now let's recover the original claims JSON (the payload).
payload = jwt.getPayload(token)
# The payload will likely be in compact form:
print(payload)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
json = chilkat.CkJsonObject()
success = json.Load(payload)
json.put_EmitCompact(False)
print(json.emit())

# We can recover the original JOSE header in the same way:
joseHeader = jwt.getHeader(token)
# The payload will likely be in compact form:
print(joseHeader)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
success = json.Load(joseHeader)
json.put_EmitCompact(False)
print(json.emit())