127 lines
3.1 KiB
Markdown
127 lines
3.1 KiB
Markdown
# cox
|
|
[](https://travis-ci.org/didactic-drunk/cox)
|
|
|
|
Updated Crystal bindings for the [libsodium API](https://libsodium.gitbook.io/doc/)
|
|
|
|
Given a recipients public key, you can encrypt and sign a message for them. Upon
|
|
receipt, they can decrypt and authenticate the message as having come from you.
|
|
|
|
## Installation
|
|
|
|
**[Install libsodium](https://download.libsodium.org/doc/installation/)**, then:
|
|
|
|
Add this to your application's `shard.yml`:
|
|
|
|
```yaml
|
|
dependencies:
|
|
cox:
|
|
github: didactic-drunk/cox
|
|
```
|
|
|
|
## Usage
|
|
|
|
```crystal
|
|
require "cox"
|
|
|
|
data = "Hello World!"
|
|
|
|
# Alice is the sender
|
|
alice = Cox::KeyPair.new
|
|
|
|
# Bob is the recipient
|
|
bob = Cox::KeyPair.new
|
|
|
|
# Encrypt a message for Bob using his public key, signing it with Alice's
|
|
# secret key
|
|
nonce, encrypted = Cox.encrypt(data, bob.public, alice.secret)
|
|
|
|
# Decrypt the message using Bob's secret key, and verify its signature against
|
|
# Alice's public key
|
|
decrypted = Cox.decrypt(encrypted, nonce, alice.public, bob.secret)
|
|
|
|
String.new(decrypted) # => "Hello World!"
|
|
```
|
|
|
|
## Public key signing
|
|
```crystal
|
|
message = "Hello World!"
|
|
|
|
signing_pair = Cox::SignKeyPair.new
|
|
|
|
# Sign the message
|
|
signature = Cox.sign_detached(message, signing_pair.secret)
|
|
|
|
# And verify
|
|
Cox.verify_detached(signature, message, signing_pair.public) # => true
|
|
```
|
|
|
|
## Secret Key Encryption
|
|
```crystal
|
|
key = Cox::SecretKey.random
|
|
|
|
message = "foobar"
|
|
encrypted, nonce = key.encrypt_easy message
|
|
|
|
# On the other side.
|
|
key = Cox::SecretKey.new key
|
|
message = key.decrypt_easy encrypted, nonce
|
|
```
|
|
|
|
## Blake2b
|
|
```crystal
|
|
key = Bytes.new Cox::Blake2B::KEY_SIZE
|
|
salt = Bytes.new Cox::Blake2B::SALT_SIZE
|
|
personal = Bytes.new Cox::Blake2B::PERSONAL_SIZE
|
|
out_size = 64 # bytes between Cox::Blake2B::OUT_SIZE_MIN and Cox::Blake2B::OUT_SIZE_MAX
|
|
data = "data".to_slice
|
|
|
|
# output_size, key, salt, and personal are optional.
|
|
digest = Cox::Blake2b.new out_size, key: key, salt: salt, personal: personal
|
|
digest.update data
|
|
output = d.hexdigest
|
|
|
|
digest.reset # Reuse existing object to hash again.
|
|
digest.update data
|
|
output = d.hexdigest
|
|
```
|
|
|
|
## Key derivation
|
|
```crystal
|
|
kdf = Cox::Kdf.new
|
|
|
|
# kdf.derive(8_byte_context, subkey_size, subkey_id)
|
|
subkey1 = kdf.derive "context1", 16, 0
|
|
subkey2 = kdf.derive "context1", 16, 1
|
|
subkey3 = kdf.derive "context2", 32, 0
|
|
subkey4 = kdf.derive "context2", 64, 1
|
|
```
|
|
|
|
## Password Hashing
|
|
```crystal
|
|
pwhash = Cox::Pwhash.new
|
|
|
|
pwhash.memlimit = Cox::Pwhash::MEMLIMIT_MIN
|
|
pwhash.opslimit = Cox::Pwhash::OPSLIMIT_MIN
|
|
|
|
pass = "1234"
|
|
hash = pwhash.hash_str pass
|
|
pwhash.verify hash, pass
|
|
```
|
|
|
|
Use `examples/pwhash_selector.cr` to help choose ops/mem limits.
|
|
|
|
|
|
## Contributing
|
|
|
|
1. Fork it ( https://github.com/didactic-drunk/cox/fork )
|
|
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
|
|
|
|
- [andrewhamon](https://github.com/andrewhamon) Andrew Hamon - creator, former maintainer
|
|
- [dorkrawk](https://github.com/dorkrawk) Dave Schwantes - contributor
|
|
- [didactic-drunk](https://github.com/didactic-drunk) - current maintainer
|