Cloaking.jl

OVERVIEW

This project constitutes a file cloaking utility that provides password-based security of a single file or a single file system archive file (E.g. .tar.gz). The utility is probably most useful in the following situations:

• Storing backups of sensitive information on the Internet
• Transporting sensitive information electronically (E.g. email) or manually (E.g. using a flash drive)

This project is dependent on Nettle.jl, using:

• Password-based Key Derivation Function version 2 (PBKDF2)
• AES256 data cryptography in Cipher-Block Chaining (CBC) mode
• Hash-based Message Authentication Code (HMAC) function SHA512

Nettle.jl reference: https://github.com/JuliaCrypto/Nettle.jl

REQUIREMENTS

• Julia JIT Compiler
• Nettle.jl

INSTALLATION

#!/usr/bin/bash

cat <<EOF | julia
import Pkg
Pkg.add(url = "https://github.com/texadactyl/Cloaking.jl")
EOF

LICENSING

This is NOT commercial software; instead, usage is covered by the GNU General Public License version 3 (2007). In a nutshell, please feel free to use the project and share it as you will but please don't sell it. Thank you!

See the LICENSE file for the GNU licensing information.

API DEMONSTRATION

Julia source code:

println("demo_cloaking: Install Cloaking.jl from github .....")
import Pkg
Pkg.add(url = "https://github.com/texadactyl/Cloaking.jl")
println("demo_cloaking: Installation completed.")

using Printf
using Cloaking

SECRET = "/etc/hosts"

CLEARTEXT_1 = "/etc/mime.types"
CIPHERTEXT = "/tmp/ciphertext.tiff"
CLEARTEXT_2 = "/tmp/recovered_cleartext.txt"

password = open(SECRET) do file
    read(file, String)
end

println("demo_cloaking: Cloaking .....")
et, ncipherbytes = cloak_file(password, CLEARTEXT_1, CIPHERTEXT)
@printf("cloak_file E.T. = %d s, # of encrypted bytes = %d\n", et, ncipherbytes)

println("demo_cloaking: Uncloaking .....")
et, nclearbytes = uncloak_file(password, CIPHERTEXT, CLEARTEXT_2)
@printf("uncloak_file E.T. = %d s, # of decrypted bytes = %d\n", et, nclearbytes)

println("demo_cloaking: Compare newly recovered cleartext to the original cleartext .....")
cmd = `cmp $CLEARTEXT_1 $CLEARTEXT_2`
if success(cmd)
    println("demo_cloaking: Successful comparison.")
else
    println("*** demo_cloaking: FAILED comparison.")
end
println("demo_cloaking: End.")

Standard output:

demo_cloaking: Install Cloaking.jl from github .....
    Updating git-repo `https://github.com/texadactyl/Cloaking.jl`
    Updating registry at `~/.julia/registries/General`
   Resolving package versions...
  No Changes to `~/.julia/environments/v1.6/Project.toml`
  No Changes to `~/.julia/environments/v1.6/Manifest.toml`
demo_cloaking: Installation completed.
demo_cloaking: Cloaking .....
cloak_file E.T. = 0 s, # of encrypted bytes = 70496
demo_cloaking: Uncloaking .....
uncloak_file E.T. = 0 s, # of decrypted bytes = 70496
demo_cloaking: Compare newly recovered cleartext to the original cleartext .....
demo_cloaking: Successful comparison.
demo_cloaking: End.

CIPHERTEXT FILE ANATOMY

The ciphertext file created by cloak_file() has the following layout:

TIFF prefix to make the file appear as a TIFF (112 bytes)
Initialization Vector (16 bytes)
Original file size as a binary Big Endian Unsigned Long Long (8 bytes)
"BOUNDARY" as a UInt8 bytearray (8 bytes)
Encrypted file data 
    (last cleartext block is padded if necessary to a 16-byte boundary)
HMAC bytearray (64 bytes)
==========================
Total overhead = 208 bytes

Feel free to add an issue for inquiries and bugs. I'll respond as soon as I can.

Richard Elkins

Dallas, Texas, USA, 3rd Rock, Sol, ...