Publickey Key : How to

Instantiate a public key object

With the configuration defaults:

from cryptopyutils.publickey import PublicKey
# create the PublicKey object with the configuration defaults
pubk = PublicKey()

or with your own configuration:

from cryptopyutils.publickey import PublicKey
from cryptopyutils.config import PublicKeyCconfig
myconfig = PublicKeyCconfig()
# you can then modify your configuration

# create the PublicKey object with your configuration
pubk = PublicKey(config=myconfig)

Generate a public key

Prior to the generation of a public key we must create or load a private key.

Example : loading a private key

from cryptopyutils.privatekey import PrivateKey
privk_filepath = "/tmp/myexample.com.pem"
privk = PrivateKey()
privk.load(filepath)

from cryptopyutils.publickey import PublicKey
# create the PublicKey object with the configuration defaults
pubk = PublicKey(private_key=privk)
# generate the RSA public key
pubk.gen()
# alternative: generate use ED25519 private key
# pubk.gen("ED25519")

Save the public key

pubk_filepath = "/tmp/myexample.com.pub"
pubk.save(pubk_filepath)

>> True

If saved it returns True, otherwise False.

Load the public key

pubk_filepath = "/tmp/mykey/myexample.com.pub"
pubk.load(pubk_filepath)

Display the public key in PEM PKCS8 format

print(pubk.keytext)

Verify a message with your public key

This example assumes you already have loaded your public key.

#Copy a valid signature (this one is invalid)
signature = b'638QWTOjdT712NOmpPi+nLBGdZ6zQ64+ZNQcOTSpyZDQv7k3mO4piHNNVHxz7L3scQgThcp1QBQR7fyrAep7Ys2ozB6bAvCI6wUSF8achgTt69HY...'
message_to_verify = b'my message to sign'
# Verify
verif = pubk.verify(signature, message_to_verify)

>> True

If verified it returns True, otherwise False.

Encrypt a message with your public key

RSA is the encryption / decryption technique supported by cryptopyutils.

This example assumes you already have loaded your public key.

# Choose the message to encrypt
message_to_encrypt = b'my message to encrypt'
# Encrypt
ciphertext = pubk.encrypt(message_to_encrypt)
# print the message
print(ciphertext)

>>  b'e83JOPUT7e6syGGoJeAyU128cde0Ck4V7/lwo+0OHu/SXB2N/e5/JEdTdvbUY+j8...'