(CkPython) Convert RSA Private Key to Public Key

Demonstrates how to get a public RSA key from a private RSA key.

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

import sys
import chilkat

key = chilkat.CkPrivateKey()

# Step 1: Load the private key from a source.
# (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
# see the online reference documentation for more options.)
success = key.LoadPemFile("qa_data/pem/VP_Private.pem")
if (success != True):
    print(key.lastErrorText())
    sys.exit()

# Step 2: Get the public key object from the private key object.
# pubKey is a CkPublicKey
pubKey = key.GetPublicKey()
if (key.get_LastMethodSuccess() != True):
    print(key.lastErrorText())
    sys.exit()

# Step 3: Save the public key in a desired format. 
# (Chilkat can load or save public and private keys in many different formats.  See
# the online reference documentation for more options.)

# Saves to a PKCS8 PEM file.
bPreferPkcs1 = False
success = pubKey.SavePemFile(bPreferPkcs1,"qa_data/pem/VP_Public.pem")
if (pubKey.get_LastMethodSuccess() != True):
    print(pubKey.lastErrorText())
    sys.exit()

print("Extracted and saved public key from private key.")