arcipher

arcipher

A Go library and CLI tool for classical cryptography and cryptanalysis. Provides implementations of historical ciphers with file processing and concurrent operations.

Overview

Library: Core cipher implementations and cryptanalysis algorithms for use in Go projects.

CLI: arcipher command-line tool for encrypting, decrypting, and analyzing text and files with support for concurrent block processing.

Ciphers

Analyzers

Padding

Math Utilities

Matrix operations and modular arithmetic utilities for classical cipher implementations.

Installation

Prerequisites

• Go 1.25.5 or later

As a Library

go get github.com/ItakawaM/arcipher

As a CLI Tool

macOS / Linux:

go build -o arcipher ./cmd/arcipher

or

make build BINARY=arcipher

Windows:

go build -o arcipher.exe ./cmd/arcipher

or

make build

Library Usage

package main

import "github.com/ItakawaM/arcipher/ciphers"

func main() {
 // Create a new cipher
 cipher, err := ciphers.NewCaesarCipher(12)
 if err != nil {
  // Process error
 }

 // Create source and destination buffers
 src := []byte("HelloWorld")
 dst := make([]byte, len(src))

 // Perform action
 if err := cipher.EncryptBlock(dst, src); err != nil {
  // Process error
 }

 // Alternatively, you can alias buffers if the desired cipher allows it
 if cipher.IsInPlace() {
  if err := cipher.EncryptBlock(src, src); err != nil {
   // Process error
  }
 }
}

CLI Usage

Basic pattern:

arcipher <CIPHER> <ACTION> <ARGS> [FLAGS]

Getting help:

arcipher <COMMAND> --help

Verbose output:

arcipher <COMMAND> --verbose

Railfence

Message Encryption/Decryption with key 3

arcipher railfence encrypt 3 "helloworld" 
arcipher railfence decrypt 3 "loelwrdhol"

File Encryption/Decryption with key 10 using 4 threads and blocks of size 1024KB and verbose output

arcipher railfence encrypt 10 ./example/SunPoem ./example/SunPoem.enc --block 1024 --threads 4 -v
arcipher railfence decrypt 10 ./example/SunPoem.enc ./example/SunPoem --block 1024 --threads 4 -v

Caesar

Message Encryption/Decryption with key 15

arcipher caesar encrypt 15 "helloworld"
arcipher caesar decrypt 15 "wtaadldgas"

Message Bruteforce and Frequency Analysis

arcipher caesar bruteforce "wtaadldgas"
arcipher caesar analyze "wtaadldgas"

File Encryption/Decryption with key 5 using 2 threads and blocks of size 256KB

arcipher caesar encrypt 5 ./example/SunPoem ./example/SunPoem.enc --block 256 --threads 2
arcipher caesar decrypt 5 ./example/SunPoem.enc ./example/SunPoem --block 256 --threads 2

File Bruteforce using 6 threads and blocks of size 2048KB and Frequency Analysis

arcipher caesar bruteforce ./example/SunPoem /example/SunPoem_Directory -t 6 -b 2048
arcipher caesar analyze ./example/SunPoem

Cardan

Message Encryption/Decryption via interactive browser UI and key export

arcipher cardan encrypt "helloworld" --export key.json
arcipher cardan decrypt "h lowd e ol  lr "

Message Encryption/Decryption with exported/generated key

arcipher cardan encrypt ./key.json "helloworld"
arcipher cardan decrypt ./key.json "h lowd e ol  lr "

Generate a key for a 5x5 grid

arcipher cardan generate-key 5 key.json

File Encryption/Decryption with key and 4 threads

arcipher cardan encrypt key.json ./example/SunPoem ./example/SunPoem.enc --threads 4 -v
arcipher cardan decrypt key.json ./example/SunPoem.enc ./example/SunPoem --threads 4 -v

Vigenere

Message Encryption/Decryption with key "Secret"

arcipher vigenere encrypt "Secret" "helloworld"
arcipher vigenere decrypt "Secret" "zincspgvnu"

Message Dictionary Bruteforce and Kasiski-Frequency Analysis

arcipher vigenere bruteforce ./example/dict.txt "zincspgvnu"
arcipher vigenere analyze "zincspgvnu"

File Encryption/Decryption with key "Keyword" using 4 threads and blocks of size 512KB

arcipher vigenere encrypt "Keyword" ./example/SunPoem ./example/SunPoem.enc --block 512 --threads 4
arcipher vigenere decrypt "Keyword" ./example/SunPoem.enc ./example/SunPoem --block 512 --threads 4

File Dictionary Bruteforce using 4 threads and Kasiski-Frequency Analysis

arcipher vigenere bruteforce ./example/dict.txt ./example/SunPoem /example/SunPoem_Directory --threads 4
arcipher vigenere analyze ./example/SunPoem.enc

Message Encryption/Decryption with Autokey variant using -a flag

arcipher vigenere encrypt "Secret" "helloworld" -a
arcipher vigenere decrypt "Secret" "zincspvvwo" -a

File Encryption/Decryption with Autokey variant using 4 threads

arcipher vigenere encrypt "Keyword" ./example/SunPoem ./example/SunPoem.enc --block 512 --threads 4 -a
arcipher vigenere decrypt "Keyword" ./example/SunPoem.enc ./example/SunPoem --block 512 --threads 4 -a

Affine

Generate an Affine cipher key

arcipher affine generate-key 3 key.json
arcipher affine generate-key 25 key.json --template

Message Encryption/Decryption with key

arcipher affine encrypt ./key.json "HELLOWORLD"
arcipher affine decrypt ./key.json "ZICVTWQNGRZGVTWAVZHCQYGLMGJ"

File Encryption/Decryption with key and 4 threads

arcipher affine encrypt key.json ./example/input ./example/input.enc --threads 4 -v
arcipher affine decrypt key.json ./example/input.enc ./example/output --threads 4 -v

Options

• -v, --verbose — Show performance metrics
• -b, --block — Block size in KB for file processing (default: 64)
• -t, --threads — Worker threads for file processing (default: CPU cores / 2)

Testing

go test ./tests/...

or

make test

License

MIT License — see LICENSE