CkPython Requires Chilkat v11.5.0+

Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card. CkPython

import sys
import chilkat

success = False

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

#  Load the certificate from a smart card.
cert = chilkat.CkCert()

#  Set the smarcard PIN prior to loading
cert.put_SmartCardPin("123456")

#  Detect the connected smartcard or USB security token and load the default certificate.
success = cert.LoadFromSmartcard("")
if (success == False):
    print(cert.lastErrorText())
    sys.exit()

#  Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
#  such as selecting a certificate if the card contains multiple certificates with private keys,
#  or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

#  Create the JWS Protected Header
jwsProtHdr = chilkat.CkJsonObject()

if (cert.IsEcdsa() == True):
    jwsProtHdr.AppendString("alg","ES256")
else:
    jwsProtHdr.AppendString("alg","RS256")

jws = chilkat.CkJws()

#  Set the protected header:
signatureIndex = 0
jws.SetProtectedHeader(signatureIndex,jwsProtHdr)

#  Provide the private key via the certificate.
#  This requires Chilkat v11.5.0 or greater.
jws.SetSigningCert(signatureIndex,cert)

#  Set the payload.
bIncludeBom = False
payloadStr = "In our village, folks say God crumbles up the old moon into stars."
jws.SetPayload(payloadStr,"utf-8",bIncludeBom)

#  Create the JWS
#  By default, the compact serialization is used.
jwsCompact = jws.createJws()
if (jws.get_LastMethodSuccess() == False):
    print(jws.lastErrorText())
    sys.exit()

print("JWS: " + jwsCompact)

#  sample output:
#  JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

#  Now load the JWS, validate, and recover the original text.
jws2 = chilkat.CkJws()

#  Load the JWS.
success = jws2.LoadJws(jwsCompact)

pubKey = chilkat.CkPublicKey()
cert.GetPublicKey(pubKey)

#  Set the public key used for validation.
signatureIndex = 0
jws2.SetPublicKey(signatureIndex,pubKey)

#  Validate the 1st (and only) signature at index 0..
v = jws2.Validate(signatureIndex)
if (v < 0):
    #  Perhaps Chilkat was not unlocked or the trial expired..
    print("Method call failed for some other reason.")
    print(jws2.lastErrorText())
    sys.exit()

if (v == 0):
    print("Invalid signature.  The key was incorrect, the JWS was invalid, or both.")
    sys.exit()

#  If we get here, the signature was validated..
print("Signature validated.")

#  Recover the original content:
print(jws2.getPayload("utf-8"))

#  Examine the protected header:

joseHeader = chilkat.CkJsonObject()
success = jws2.GetProtectedH(signatureIndex,joseHeader)
if (success == False):
    print(jws2.lastErrorText())
    sys.exit()

joseHeader.put_EmitCompact(False)

print("Protected (JOSE) header:")
print(joseHeader.emit())

#  Output:

#  	Signature validated.
#  	In our village, folks say God crumbles up the old moon into stars.
#  	Protected (JOSE) header:
#  	{ 
#  	  "alg": "RS256"
#  	}