swap64

Multi-threaded, scalable, x64 CBC 4096-bit block cipher that performs 7 rounds per block w/ an NLFSR key schedule, key dependant movements, and a 512-bit OTP key seed masked w/ passphrase hash.

Currently, this only works on Linux(Maybe Mac) as it uses /dev/random for seeding but I will probably update this to crypto-rand later so that it works on all OSs.

Build with

chmod +x build && ./build

Run with

./swap64 fileName

Alternatively you can run without any arguments or with -h/--help to show the usage information.

Encrypted files have a .sp extension and swap64 will default to fwd and rev operating modes (-o/--opmode) based on the extension unless otherwise specified in case you want to encrypt something multiple times.

You can specify threads with -t/--threads otherwise it will default to 0 which uses the number of CPUs.

The number of rounds per block can also be specified via -r/--rounds (defaults to 7) but be aware that this value is not stored in the file anywhere so you MUST specify it at encryption AND decryption time. Also, due to the design of the cipher, increasing the rounds doesn't necessarily make it any more secure as the shuffle still only happens one time and the rounds are a shift of that shuffled block so since it shifts 512 bits per round, the 8th round would circle back to the original placement. It may add "some" additional security but just be aware that the blocks are not actually being cycled through the entire cipher each round.

Note: There is no hash checking of the passphrase so you can decrypt with any passphrase you like and it will process the file but you will end up with a binary blob of nothing. XD