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https://github.com/ivan-guerra/caesar_cipher
Caesar Cipher encrypt/decrypt/cracking utilities
https://github.com/ivan-guerra/caesar_cipher
caesar-cipher cryptography password-cracking
Last synced: 17 days ago
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Caesar Cipher encrypt/decrypt/cracking utilities
- Host: GitHub
- URL: https://github.com/ivan-guerra/caesar_cipher
- Owner: ivan-guerra
- License: unlicense
- Created: 2024-04-05T06:07:00.000Z (10 months ago)
- Default Branch: master
- Last Pushed: 2024-11-10T17:00:52.000Z (3 months ago)
- Last Synced: 2024-11-10T18:17:01.295Z (3 months ago)
- Topics: caesar-cipher, cryptography, password-cracking
- Language: Rust
- Homepage: https://programmador.com/posts/2024/caesar-cipher/
- Size: 97.7 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Caesar Cipher Tools
This repo contains [Caesar Cipher][1] encode, decode, and cracking utilities.
These utilities only support the ASCII character set.
### Encoding/Decoding Messages
The `ccipher` utility encodes/decodes messages. Below is the `ccipher` usage
message:
```text
Caesar Cipher encryption/decryption utility.
Usage: ccipher [OPTIONS]
Arguments:
encryption/decryption key
Options:
-i, --input-file input plaintext/ciphertext file
-o, --output-file output plaintext/ciphertext file
-h, --help Print help
-V, --version Print version
```
`ccipher` accepts input from `STDIN` or from a file if one is specified via the
`--input-file` option. Ciphertext is output to `STDOUT` by default but can also
be written to file via shell redirection or the `--output-file` option.
In the example below, we encrypt the contents of a file, `plaintext`, containing
the string `hello` using the key `27`. The output of the encrypt operation is
sent to the file `ciphertext`. Another call to `ccipher` with a key of `-27`
decrypts the contents of `ciphertext` to `STDOUT`.
```text
echo "hello" > plaintext
./ccipher -k 27 -i plaintext -o ciphertext
./ccipher -k -27 -i ciphertext
```
### Code Cracking
The `ccracker` utility takes as input ciphertext produced by a Caesar Cipher and
outputs the key that most probably decrypts the text. You can take the
ciphertext and the key output by `ccracker` and use them as input to `ccipher`
to retrieve the secret message.
Below is the `ccracker` usage message:
```
Caesar cipher cracker.
Usage: ccracker [OPTIONS]
Options:
-i, --ciphertext-file
file containing ciphertext
-a, --attack
attack type [default: dictionary] [possible values: dictionary, frequency]
-h, --help
Print help (see more with '--help')
-V, --version
Print versiontext
```
`ccracker` reads ciphertext input from `STDIN` by default. Optionally, you can
supply the ciphertext in a file using the `--ciphertext-file` option. `ccracker`
implements two cracking algorithms: a dictionary attack and a frequency analysis
attack. The dictionary attack is the default option. You can chose to run a
frequency attack with the `--attack frequency` option.
Below is an example of cracking a message using the dictionary attack:
```text
echo "**-H" | ./ccracker
```
The output of the above command is `candidate key: 66`. We can apply this key to
the ciphertext using `ccipher`:
```text
echo "**-H" | ./ccipher -k 66
```
The output will be the plaintext message `hello`!
### References
- [Popular English Words Dictionary][2]
- [ASCII Character Frequency Table][3]
[1]: https://en.wikipedia.org/wiki/Caesar_cipher#
[2]: https://github.com/dolph/dictionary
[3]: https://github.com/piersy/ascii-char-frequency-english?tab=readme-ov-file