Chilkat2-Python

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. Chilkat2-Python

import sys
import chilkat2

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 = chilkat2.Prng()
eccClient = chilkat2.Ecc()
privKeyClient = chilkat2.PrivateKey()
success = eccClient.GenKey("secp256r1",prngClient,privKeyClient)
if (success == False):
    print(eccClient.LastErrorText)
    sys.exit()

pubKeyClient = chilkat2.PublicKey()
privKeyClient.ToPublicKey(pubKeyClient)
pubKeyClient.SavePemFile(False,"qa_output/eccClientPub.pem")

# -----------------------------------------------------------------
# (Server-Side) Generate an ECC key, save the public part to a file.
# -----------------------------------------------------------------
prngServer = chilkat2.Prng()
eccServer = chilkat2.Ecc()
privKeyServer = chilkat2.PrivateKey()
eccServer.GenKey("secp256r1",prngServer,privKeyServer)

pubKeyServer = chilkat2.PublicKey()
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 = chilkat2.PublicKey()
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 = chilkat2.PublicKey()
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)