Plasm is a simple PyNaCl abstraction module to easily integrate file encryption into python projects. It makes key generation and file encryption/decryption very simple. Plasm uses the sealedBox construct. The sealedBox uses key pairs of public and private keys. This allows encrypt using only a public key. That way the private key required for decryption can be stored in a safe place away from the machine that does the encryption. The private key is also encrypted itself using a password. This password is specified during the creation of the key pair. During decryption of a file encrypted with the public key, the private key is first decrypted using the password specified before it's creation and then used to decrypt the file.

If you are willing to dive deeper or want to customize more than what plasm allows to, feel free to check out PyNaCl's documentation and use it directly.

• memlimit is optional and specifies the amount of RAM occupied for encrypting the private key in bytes. It's set to 1073741824 bytes (1,07 gigabytes) by default, because that's the memlimit for sensitive data libsodium suggests. If you specify a memlimit exceeding the free RAM your device can offer, creating the key will fail. If your encrypting device (e.g. a Raspberry Pi with ~500 megabytes of RAM) can't offer the default, I suggest creating the keys on a device that does and transferring them to the other device instead of weakening the encryption of your private key by creating it with a lower memlimit.

from plasm import gen_keys

gen_keys.generate_key_pair(private_key_location, public_key_location, password, memlimit=1073741824)

• remove_input_file is optional and False by default.

from plasm import encrypt

encrypt.encrypt_file(my_file, public_key_location, remove_input_file=True)

• outfile_extension is optional and set to ".crypt" by default
• remove_input_file is optional and False by default.

from plasm import encrypt

encrypt.encrypt_files_in_dir(directory, public_key_location, outfile_extension=".crypt", remove_input_file=False):

from plasm import decrypt

decrypt.decrypt_file(encrypted_file, private_key_location, password)

• infile_extension is optional and set to ".crypt" by default

from plasm import decrypt

decrypt.decrypt_files_in_dir(directory, private_key_location, password, infile_extension=".crypt"):

plasm offers a test suite based on pytest. To run all tests, move to the root directory of plasm and run pytest:

python -m pytest tests

If you want a coverage report, use this command:

python -m pytest --cov=plasm --cov-report term-missing tests