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Chilkat2-Python

RSA Encrypt/Decrypt Bytes

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Demonstrates how to RSA encrypt and decrypt byte data.

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Chilkat2-Python
import sys
import chilkat2

success = False

# The RSA public key is used for encryption, and the private key for decryption.

# The public key's role is to make encryption accessible to anyone while ensuring that
# only the private key holder can decrypt the messages.
# The public key is designed to be widely distributed so anyone can use it to encrypt messages
# intended for the owner of the private key.

# Load our 2048-bit RSA public key.
pubKey = chilkat2.PublicKey()
# In all Chilkat methods expecting a path, you pass either absolute or relative paths.
success = pubKey.LoadFromFile("qa_data/rsaKeys/myTestRsaPublic.pem")
if (success == False):
    print(pubKey.LastErrorText)
    sys.exit()

rsa = chilkat2.Rsa()

# Tell RSA to use the public key.
rsa.UsePublicKey(pubKey)

# RSA encryption is for small amounts of data, on the order of 200 bytes or less.
# The maximum number of bytes that can be RSA encrypted depends
# on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
# For specific limits, see: RSA Encryption Maximum Number of Bytes

# A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
prng = chilkat2.Prng()

# keyBytes is a memoryview
keyBytes = prng.GenRandomBytes(32)

# encBytes is a memoryview
encBytes = rsa.EncryptBytes(keyBytes,False)

# ------------------------------------------------------------------------------------------------------------------------
# Let's decrypt, which requires the matching private key...

# Load the matching 2048-bit RSA private key.
privKey = chilkat2.PrivateKey()
password = "secret"
success = privKey.LoadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem",password)
if (success == False):
    print(privKey.LastErrorText)
    sys.exit()

# Tell the RSA object to use the private key.
rsa.UsePrivateKey(privKey)

# decBytes is a memoryview
decBytes = rsa.DecryptBytes(encBytes,True)
if (success == False):
    print(rsa.LastErrorText)
    sys.exit()

print("Success.")