mcencrypt

MCENCRYPT is abbreviated from "MCeliece8192128 ENCRYPTion tool".

About

Post-quantum public-key encryption/decryption tool which uses public key to encrypt and secret key to decrypt message. It contains mckeypair,mcencrypt,mcdecrypt. The tool in inspirated in https://libpqcrypto.org/command.html (encryption systems), uses same commandline interface.

mckeypair is used to generate a key pair:

mckeypair 5>publickey 9>secretkey

mcencrypt is used to encrypt a message:

mcencrypt <message 4<publickey >ciphertext

mcdecrypt is used to decrypt a ciphertext and recover the original message:

mcdecrypt <ciphertext 8<secretkey >message

How it works

mckeypair creates randomly generated a mceliece8192128 secret key, a corresponding public key, writes public key on filedescriptor 5 and also writes secret key on filedescriptor 9.

14080 BYTES mceliece8192128 secret key

1357824 BYTES mceliece8192128 public key

mcencrypt reads mceliece8192128 public key from filedescriptor 4, uses KEM (key encapsulation mode) to compute symetric session key and ciphertext. Then reads n-BYTES message from standard input, uses chacha20-poly1305 to encrypt and authenticate the message and writes ciphertext on standard output.

240 BYTES mceliece8192128 ciphertext
n BYTES chacha20 encrypted message
16 BYTES poly1305 authenticator

mcdecrypt reads mceliece8192128 secret key from filedescriptor 8, uses ciphertext/secret key to compute session key. Then reads ciphertext,encrypted message from standard input, uses chacha20-poly1305 to verify,decrypt and write the decrypted message on standard output. If decryption fails, mcdecrypt produces an empty output, prints an error message on stderr, and exits 100.

Crypto

mcencrypt uses post-quantum safe crypto-algorithms:

• mceliece8192128 public-key code-based crypto-system, see mceliece-20171129.pdf
• chacha20-poly1305 symetric encryption/authentication, see chacha-20080128.pdf, poly1305-20041101.pdf

Example

#create key-pair
umask 077
mckeypair 5>pk 9>sk

#encrypt tarball
(cd somewhere; tar -vjcf - *) | mcencrypt 4<pk >data.tar.bz2.mc8

#decrypt tarball
mcdecrypt 8<sk <data.tar.bz2.mc8 | (cd somewhere; tar -vjxf -)

Implementation notes

mceliece8192128 public-domain implementation taken from https://classic.mceliece.org/software.html, files benes.c, benes.h, bm.c, bm.h, controlbits.c, controlbits.h, decrypt.c, decrypt.h, encrypt.c, encrypt.h, gf.c, gf.h, operations.c, params.h, root.c, root.h, sk_gen.c, sk_gen.h, synd.c, synd.h, transpose.c, transpose.h, util.c, util.h and modified to use SHA512 instead of SHA3256.
poly1305 public-domain implementation based on https://github.com/floodyberry/poly1305-donna

1TB test

computer

cat /proc/cpuinfo | grep 'model name' | sort | uniq -c
     32 model name	: Intel(R) Xeon(R) CPU E5-2630L v3 @ 1.80GHz

df -h | grep sda5
/dev/sda5        11T  1.6T  9.4T  14% /

create keys

time -p mckeypair 5>pk 9>sk
real 1.44
user 1.24
sys 0.20

create 1TB file

dd if=/dev/urandom of=data bs=1 count=1099511627789 2>/dev/null

encrypt

time -p mcencrypt <data 4<pk >data.mc8
real 8650.60
user 4030.29
sys 1003.61

decrypt

time -p mcdecrypt <data.mc8 8<sk >data.new
real 12071.66
user 5544.74
sys 1394.20

compare checksums

test "`shasum < data`" = "`shasum < data.new`" 

result

encryption 121MB/s
decryption 86MB/s