sodium.cr/README.md

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# sodium.cr
[![Build Status](https://travis-ci.org/didactic-drunk/sodium.cr.svg?branch=master)](https://travis-ci.org/didactic-drunk/sodium.cr)
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Crystal bindings for the [libsodium API](https://libsodium.gitbook.io/doc/)
## Goals
* Provide the most commonly used libsodium API's.
* Provide an easy to use API based on reviewing most other [libsodium bindings](https://libsodium.gitbook.io/doc/bindings_for_other_languages).
* Test for compatibility against other libsodium bindings to ensure interoperability.
* Always provide a stream interface to handle arbitrarily sized data when one is available.
* Drop in replacement classes compatible with OpenSSL::{Digest,Cipher} when possible.
* Use the newest system packaged libsodium or download the most recent stable version without manual configuration.
## Features
- [Public-Key Cryptography](https://libsodium.gitbook.io/doc/public-key_cryptography)
- [x] ☑ [Crypto Box Easy](https://libsodium.gitbook.io/doc/public-key_cryptography/authenticated_encryption)
- [x] [Sealed Box](https://libsodium.gitbook.io/doc/public-key_cryptography/sealed_boxes)
- [ ] [Combined Signatures](https://libsodium.gitbook.io/doc/public-key_cryptography/public-key_signatures)
- [x] ☑ [Detached Signatures](https://libsodium.gitbook.io/doc/public-key_cryptography/public-key_signatures)
- [ ] [Pre-hashed Signatures](https://libsodium.gitbook.io/doc/public-key_cryptography/public-key_signatures)
- [Secret-Key Cryptography](https://libsodium.gitbook.io/doc/secret-key_cryptography)
- Secret Box
- [x] ☑ [Combined mode](https://libsodium.gitbook.io/doc/secret-key_cryptography/authenticated_encryption)
- [ ] [Detached mode](https://libsodium.gitbook.io/doc/secret-key_cryptography/authenticated_encryption)
- [x] [Secret Stream](https://libsodium.gitbook.io/doc/secret-key_cryptography/secretstream)
- [AEAD](https://libsodium.gitbook.io/doc/secret-key_cryptography/aead)
- [ ] AES256-GCM (Requires hardware acceleration)
- [x] ☑ [XChaCha20-Poly1305-IETF](https://libsodium.gitbook.io/doc/secret-key_cryptography/aead/chacha20-poly1305/xchacha20-poly1305_construction)
- [ ] [ChaCha20-Poly1305-IETF](https://libsodium.gitbook.io/doc/secret-key_cryptography/aead/chacha20-poly1305/ietf_chacha20-poly1305_construction)
- [ ] [ChaCha20-Poly1305](https://libsodium.gitbook.io/doc/secret-key_cryptography/aead/chacha20-poly1305)
- [x] Combined and detached mode
- [Hashing](https://libsodium.gitbook.io/doc/hashing)
- [x] ☑ [Blake2b](https://libsodium.gitbook.io/doc/hashing/generic_hashing)
- [x] Complete libsodium implementation including `key`, `salt`, `personal` and fully selectable output sizes.
- [ ] [SipHash](https://libsodium.gitbook.io/doc/hashing/short-input_hashing)
- [Password Hashing](https://libsodium.gitbook.io/doc/password_hashing)
- [x] ☑ [Argon2](https://libsodium.gitbook.io/doc/password_hashing/the_argon2i_function) (Use for new applications)
- [ ] [Scrypt](https://libsodium.gitbook.io/doc/advanced/scrypt) (For compatibility with older applications)
- Other
- [x] [Key Derivation](https://libsodium.gitbook.io/doc/key_derivation)
- [ ] [Key Exchange](https://libsodium.gitbook.io/doc/key_exchange)
- [Advanced](https://libsodium.gitbook.io/doc/advanced)
- [Stream Ciphers](https://libsodium.gitbook.io/doc/advanced/stream_ciphers)
- [x] XSalsa20
- [x] Salsa20
- [x] XChaCha20
- [x] ChaCha20 Ietf
- [x] ChaCha20
- [x] Easy to use methods available for use as a CSPRNG that are faster and safer than Crystal's. See `benchmarks/rand.out`.
- [ ] [One time auth](https://libsodium.gitbook.io/doc/advanced/poly1305)
- [ ] Padding
- Library features
- [x] Faster builds by requiring what you need (`require "sodium/secret_box"`)
- [x] Nonce reuse detection.
- [x] All SecretKey's held in libsodium guarded memory.
- [x] No heap allocations after #initialize when possible.
- [x] Fast. Benchmarks available in `benchmarks`.
- [x] [Most classes are safe to share between threads.](THREAD_SAFETY.md)
- [x] Tested with real crystal threads and will continue to work when crystal officially supports threading.
- [x] Most classes are safe to share between threads. Even
- [ ] Controlled memory wiping (by calling `.close`)
☑ Indicate specs are compared against test vectors from another source.
Several features in libsodium are already provided by Crystal:
* Random (Use [Random::Secure](https://crystal-lang.org/api/latest/Random/Secure.html))
* SHA-2 (Use [OpenSSL::Digest](https://crystal-lang.org/api/latest/OpenSSL/Digest.html))
* HMAC SHA-2 (Use [OpenSSL::HMAC](https://crystal-lang.org/api/latest/OpenSSL/HMAC.html))
* Hex conversion (Use [String#hexbytes](https://crystal-lang.org/api/latest/String.html#hexbytes%3ABytes-instance-method))
## What should I use for my application?
| Class | |
| --- | --- |
| Only use `CryptoBox::SecretKey` `Sign::SecretKey` `SecretBox` | I don't know much about crypto. |
| [`Sodium::CryptoBox::SecretKey`](https://didactic-drunk.github.io/sodium.cr/Sodium/CryptoBox/SecretKey.html) .box | I want to encrypt + authenticate data using public key encryption. |
| [`Sodium::CryptoBox::SecretKey`](https://didactic-drunk.github.io/sodium.cr/Sodium/CryptoBox/PublicKey.html) .encrypt | I want anonymously send encrypted data. (No signatures) |
| [`Sodium::Sign::SecretKey`](https://didactic-drunk.github.io/sodium.cr/Sodium/Sign/SecretKey.html) | I want to sign or verify messages. (No encryption) |
| [`Sodium::SecretBox`](https://didactic-drunk.github.io/sodium.cr/Sodium/SecretBox.html) | I have a shared key and want to encrypt + authenticate data. |
| [`Sodium::Cipher::Aead::XChaCha20Poly1305Ietf`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/Aead/XChaCha20Poly1305Ietf.html) | I have a shared key and want to encrypt + authenticate data and authentication additional plaintext data. |
| [`Sodium::Cipher::SecretStream`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/SecretStream/XChaCha20Poly1305.html) | I have a shared key and want encrypt + authenticate streamed data. |
| [`Sodium::Digest::Blake2b`](https://didactic-drunk.github.io/sodium.cr/Sodium/Digest/Blake2b.html) | I want to hash data fast and securely. |
| `Sodium::Digest::SipHash` | I want to hash data really fast and less securely. (Not implemented yet) |
| [`Sodium::Password::Hash`](https://didactic-drunk.github.io/sodium.cr/Sodium/Password/Hash.html) | I want to hash a password and store it. |
| [`Sodium::Password::Key`](https://didactic-drunk.github.io/sodium.cr/Sodium/Password/Key.html) | I want to derive a key from a password. |
| [`Sodium::Kdf`](https://didactic-drunk.github.io/sodium.cr/Sodium/Kdf.html) | I have a high quality master key and want to make subkeys. |
| [`Sodium::Cipher::Chalsa`](https://didactic-drunk.github.io/sodium.cr/Sodium/Cipher/Chalsa.html) | What goes with guacamole? |
| Everything else | I want to design my own crypto protocol and probably do it wrong. |
## Installation
**[Optionally Install libsodium.](https://download.libsodium.org/doc/installation/)**
A recent version of libsodium is automatically downloaded and compiled if you don't install your own version.
Add this to your application's `shard.yml`:
```yaml
dependencies:
sodium:
github: didactic-drunk/sodium.cr
```
## Usage
See `examples` for help on using these classes in a complete application.
The `specs` provide the best examples of how to use or misuse individual classes.
```
### CryptoBox authenticated easy encryption
```crystal
require "sodium"
data = "Hello World!"
# Alice is the sender
alice = Sodium::CryptoBox::SecretKey.new
# Bob is the recipient
bob = Sodium::CryptoBox::SecretKey.new
# Precompute a shared secret between alice and bob.
box = alice.box bob.public_key
# Encrypt a message for Bob using his public key, signing it with Alice's
# secret key
encrypted, nonce = box.encrypt data
# Precompute within a block. The shared secret is wiped when the block exits.
bob.box alice.public_key do |box|
# Decrypt the message using Bob's secret key, and verify its signature against
# Alice's public key
decrypted = box.decrypt encrypted, nonce: nonce
String.new(decrypted) # => "Hello World!"
end
```
### Unauthenticated public key encryption
```crystal
data = "Hello World!"
# Bob is the recipient
bob = Sodium::CryptoBox::SecretKey.new
# Encrypt a message for Bob using his public key
encrypted = bob.public_key.encrypt data
# Decrypt the message using Bob's secret key
decrypted = bob.decrypt encrypted
String.new(decrypted) # => "Hello World!"
```
### Public key signing
```crystal
message = "Hello World!"
secret_key = Sodium::Sign::SecretKey.new
# Sign the message
signature = secret_key.sign_detached message
# Send secret_key.public_key to the recipient
# On the recipient
public_key = Sodium::Sign::PublicKey.new key_bytes
# raises Sodium::Error::VerificationFailed on failure.
public_key.verify_detached message, signature
```
### Secret Key Encryption
```crystal
box = Sodium::SecretBox.new
message = "foobar"
encrypted, nonce = box.encrypt message
# On the other side.
box = Sodium::SecretKey.new key
message = box.decrypt encrypted, nonce: nonce
```
### Blake2b
```crystal
key = Bytes.new Sodium::Digest::Blake2B::KEY_SIZE
salt = Bytes.new Sodium::Digest::Blake2B::SALT_SIZE
personal = Bytes.new Sodium::Digest::Blake2B::PERSONAL_SIZE
out_size = 64 # bytes between Sodium::Digest::Blake2B::OUT_SIZE_MIN and Sodium::Digest::Blake2B::OUT_SIZE_MAX
data = "data".to_slice
# output_size, key, salt, and personal are optional.
digest = Sodium::Digest::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 = Sodium::Kdf.new
# kdf.derive(8_byte_context, subkey_id, subkey_size)
subkey1 = kdf.derive "context1", 0, 16
subkey2 = kdf.derive "context1", 1, 16
subkey3 = kdf.derive "context2", 0, 32
subkey4 = kdf.derive "context2", 1, 64
```
### Password based keys
```crystal
pwcreate = Sodium::Password::Key::Create.new
# Take approximately 1 second to derive a key.
pwcreate.tcost = 1.0
pass = "1234"
key, params = pwcreate.create_key pass
# Store `params` or `params.to_h` for later.
# Derive the same key from the stored params.
pwkey = Sodium::Password::Key.from_params params.to_h
key = pekey.derive_key pass
```
### Password Hashing
```crystal
pwhash = Sodium::Password::Hash.new
pwhash.mem = Sodium::Password::MEMLIMIT_MIN
pwhash.ops = Sodium::Password::OPSLIMIT_MIN
pass = "1234"
hash = pwhash.create pass
pwhash.verify hash, pass
```
Use `examples/pwhash_selector.cr` to help choose ops/mem limits.
Example output:
Ops limit →
| | 1 | 4 | 16 | 64 | 256 | 1024 | 4096 | 16384 | 65536 | 262144 | 1048576 |
| -------- | ------- | ------- | ------- | ------- | ------- | ------- | ------- | ------- | ------- | ------- | ------- |
| 8K | | | | | | | | | | 0.542s | 2.114s |
| 32K | | | | | | | | | 0.513s | 2.069s |
| 128K | | | | | | | | 0.530s | 2.121s |
| 512K | | | | | | | 0.566s | 2.237s |
| 2048K | | | | | | 0.567s | 2.290s |
| 8192K | | | | | 0.670s | 2.542s |
| 32768K | | | | 0.684s | 2.777s |
| 131072K | | | 0.805s | 3.106s |
| 524288K | 0.504s | 1.135s | 3.661s |
| 2097152K | 2.119s |
| Memory |
## Contributing
1. Fork it ( https://github.com/didactic-drunk/sodium.cr/fork )
2. **Install a formatting check git hook (ln -sf ../../scripts/git/pre-commit .git/hooks)**
3. Create your feature branch (git checkout -b my-new-feature)
4. Commit your changes (git commit -am 'Add some feature')
5. Push to the branch (git push origin my-new-feature)
6. Create a new Pull Request
## Project History
* Originally created by [Andrew Hamon](https://github.com/andrewhamons/cox)
* Forked by [Didactic Drunk](https://github.com/didactic-drunk/cox) for lack of updates in the original project.
* Complaints about the name being too controversial. Project name changed from "cox" to a more libsodium related name of "salty seaman".
* ~50% complete libsodium API.
* More complaints about the name. Dead hooker jokes added.
* None of the original API is left.
* More complaints threatening a boycott. Told them "Go ahead, I own Coca Cola and Water".
* Account unsuspended.
* Unrelated to the boycott the project name changed to "libsodium" because sodium happens to be a tasty byproduct of the two earlier names.
* Account unsuspended.
* Dead hooker jokes (mostly) removed.
## 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