79 lines
2.0 KiB
Markdown
79 lines
2.0 KiB
Markdown
# cox
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[](https://travis-ci.org/andrewhamon/cox)
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Crystal bindings for the [libsodium box API](https://download.libsodium.org/doc/public-key_cryptography/authenticated_encryption.html)
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Given a recipients public key, you can encrypt and sign a message for them. Upon
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receipt, they can decrypt and authenticate the message as having come from you.
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## Installation
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**[Install libsodium](https://download.libsodium.org/doc/installation/)**, then:
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Add this to your application's `shard.yml`:
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```yaml
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dependencies:
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cox:
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github: andrewhamon/cox
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```
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## Usage
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```crystal
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require "cox"
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data = "Hello World!"
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# Alice is the sender
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alice = Cox::KeyPair.new
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# Bob is the recipient
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bob = Cox::KeyPair.new
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# Encrypt a message for Bob using his public key, signing it with Alice's
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# secret key
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nonce, encrypted = Cox.encrypt(data, bob.public, alice.secret)
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# Decrypt the message using Bob's secret key, and verify its signature against
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# Alice's public key
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decrypted = Cox.decrypt(encrypted, nonce, alice.public, bob.secret)
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String.new(decrypted) # => "Hello World!"
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# Public key signing
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message = "Hello World!"
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signing_pair = Cox::SignKeyPair.new
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# Sign the message
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signature = Cox.sign_detached(message, signing_pair.secret)
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# And verify
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Cox.verify_detached(signature, message, signing_pair.public) # => true
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```
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# Key derivation
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kdf = Cox::Kdf.new
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# kdf.derive(8_byte_context, subkey_size, subkey_id)
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subkey1 = kdf.derive "context1", 16, 0
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subkey2 = kdf.derive "context1", 16, 1
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subkey3 = kdf.derive "context2", 32, 0
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subkey4 = kdf.derive "context2", 64, 1
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## Contributing
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1. Fork it ( https://github.com/andrewhamon/cox/fork )
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2. Create your feature branch (git checkout -b my-new-feature)
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3. Commit your changes (git commit -am 'Add some feature')
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4. Push to the branch (git push origin my-new-feature)
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5. Create a new Pull Request
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## Contributors
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- [andrewhamon](https://github.com/andrewhamon) Andrew Hamon - creator, maintainer
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- [dorkrawk](https://github.com/dorkrawk) Dave Schwantes - contributor
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