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https://github.com/threez/rfc8439.cr
Crystal implementation ChaCha20 stream cipher as well as the Poly1305 authenticator and the AEAD mode defined in rfc8439.
https://github.com/threez/rfc8439.cr
aead chacha20 crystal poly1305 rfc8439
Last synced: 16 days ago
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Crystal implementation ChaCha20 stream cipher as well as the Poly1305 authenticator and the AEAD mode defined in rfc8439.
- Host: GitHub
- URL: https://github.com/threez/rfc8439.cr
- Owner: threez
- License: mit
- Created: 2024-07-17T19:54:45.000Z (4 months ago)
- Default Branch: main
- Last Pushed: 2024-07-21T10:33:04.000Z (4 months ago)
- Last Synced: 2024-10-08T21:40:59.117Z (about 1 month ago)
- Topics: aead, chacha20, crystal, poly1305, rfc8439
- Language: Crystal
- Homepage: https://threez.github.io/rfc8439.cr/
- Size: 67.4 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# rfc8439
Pure* crystal implementation **ChaCha20** stream cipher as well as the **Poly1305** authenticator defined in rfc8439.
(* uses BigInt and therefore `gmp`)
## Installation
1. Add the dependency to your `shard.yml`:
```yaml
dependencies:
rfc8439:
github: threez/rfc8439.cr
```
2. Run `shards install`
## Usage
### ChaCha20
```crystal
require "rfc8439"
# key and nonce are usually given using Bytes,
# but for convinience can be done as a hex string
key = "00:01:02:03:04:05:06:07:08:09:0a:0b:0c:0d:0e:0f:10:11:12:13:14:15:16:17:18:19:1a:1b:1c:1d:1e:1f"
nonce = "00:00:00:09:00:00:00:4a:00:00:00:00"
msg = "Hello World".to_slice
cipher = Crypto::ChaCha20.new(key, nonce)
encrypted = cipher.encrypt(msg)
# encryption is done using XOR so decryption is done
# by encrypting the cypher text
cipher = Crypto::ChaCha20.new(key, nonce)
plaintext = cipher.encrypt(encrypted)
puts plaintext
```
### Poly1305
```crystal
require "rfc8439"
key = "85:d6:be:78:57:55:6d:33:7f:44:52:fe:42:d5:06:a8:01:03:80:8a:fb:0d:b2:fd:4a:bf:f6:af:41:49:f5:1b"
msg = "Cryptographic Forum Research Group".to_slice
mac = Crypto::Poly1305.new(key)
mac.update(msg)
tag = mac.final
puts tag
```
### AEADChaCha20Poly1305
Writes the cipher text to `ciphertext` an `IO` target and returns the
16 byte (128 bit) Tag for the text.
```crystal
require "rfc8439"
key = Crypto::Hex.bytes("00:01:02:03:04:05:06:07:08:09:0a:0b:0c:0d:0e:0f:10:11:12:13:14:15:16:17:18:19:1a:1b:1c:1d:1e:1f")
nonce = Crypto::Hex.bytes("00:00:00:09:00:00:00:4a:00:00:00:00")
ciphertext = IO::Memory.new
aead = Crypto::AeadChacha20Poly1305.new(key, nonce, ciphertext)
aead.aad("Header".to_slice)
aead.update("Hello World!".to_slice)
tag = aead.final
puts tag
```
## Contributing
1. Fork it ()
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request
## Contributors
- [Vincent Landgraf](https://github.com/threez) - creator and maintainer