CkPython Requires Chilkat v11.0.0+

How to Generate an Elliptic Curve Shared Secret

See more ECC Examples

Demonstrates how to generate an ECC (Elliptic Curve Cryptography) shared secret. Imagine a cilent has one ECC private key, the server has another. A shared secret is computed by each side providing it's public key to the other. The private keys are kept private. CkPython

import sys
import chilkat

success = False

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

#  This example includes both client-side and server-side code.
#  Each code segment is marked as client-side or server-side.
#  Imagine these segments are running on separate computers...

#  -----------------------------------------------------------------
#  (Client-Side) Generate an ECC key, save the public part to a file.
#  -----------------------------------------------------------------
prngClient = chilkat.CkPrng()
eccClient = chilkat.CkEcc()
privKeyClient = chilkat.CkPrivateKey()
success = eccClient.GenKey("secp256r1",prngClient,privKeyClient)
if (success == False):
    print(eccClient.lastErrorText())
    sys.exit()

pubKeyClient = chilkat.CkPublicKey()
privKeyClient.ToPublicKey(pubKeyClient)
pubKeyClient.SavePemFile(False,"qa_output/eccClientPub.pem")

#  -----------------------------------------------------------------
#  (Server-Side) Generate an ECC key, save the public part to a file.
#  -----------------------------------------------------------------
prngServer = chilkat.CkPrng()
eccServer = chilkat.CkEcc()
privKeyServer = chilkat.CkPrivateKey()
eccServer.GenKey("secp256r1",prngServer,privKeyServer)

pubKeyServer = chilkat.CkPublicKey()
privKeyServer.ToPublicKey(pubKeyServer)
pubKeyServer.SavePemFile(False,"qa_output/eccServerPub.pem")

#  -----------------------------------------------------------------
#  (Client-Side) Generate the shared secret using our private key, and the other's public key.
#  -----------------------------------------------------------------

#  Imagine that the server sent the public key PEM to the client.
#  (This is simulated by loading the server's public key from the file.
pubKeyFromServer = chilkat.CkPublicKey()
pubKeyFromServer.LoadFromFile("qa_output/eccServerPub.pem")
sharedSecret1 = eccClient.sharedSecretENC(privKeyClient,pubKeyFromServer,"base64")

#  -----------------------------------------------------------------
#  (Server-Side) Generate the shared secret using our private key, and the other's public key.
#  -----------------------------------------------------------------

#  Imagine that the client sent the public key PEM to the server.
#  (This is simulated by loading the client's public key from the file.
pubKeyFromClient = chilkat.CkPublicKey()
pubKeyFromClient.LoadFromFile("qa_output/eccClientPub.pem")
sharedSecret2 = eccServer.sharedSecretENC(privKeyServer,pubKeyFromClient,"base64")

#  ---------------------------------------------------------
#  Examine the shared secrets.  They should be the same.
#  Both sides now have a secret that only they know.
#  ---------------------------------------------------------
print(sharedSecret1)
print(sharedSecret2)