Precrypt: Rust CLI for proxy-based re-encryption.

This is a CLI wrapper for the umbral-pre proxy-based re-encryption library. It adds parallel processing for encryption and decryption making it possible to process large files.

Usage

1) Encrypt your file

Generate a keypair that will be used to encrypt the file. Keep this key private, anyone who has access to it can decrypt your file.

precrypt keygen key.json

Encrypt your target file with your keypair and generate a re-encryption key..

precrypt encrypt secret.txt key.json recrypt.json out.txt

encrypt uses 10 threads by default, you can adjust this with the -t argument.

Note: We did not need a recipients public key when encrypting the file. This is the magic of proxy re-encryption, you can re-encrypt the file to a new public key at any point using a re-encryption key! This saves compute resources because you only need to encrypt the file once.

2) Recrypt your file to a public key

To give someone access to a file you will need their public key (they can generate one using the keygen command).

precrypt recrypt recrypt.json <pubkey> decrypt.json

This will create a decryption key that they can combine with their secret key to decrypt the file.

3) Decrypt the file

The recipient can now decrypt the file using their private key and the decryption key.

precrypt decrypt out.txt decrypt.json recipient_key.json decrypted_secret.txt