# crypto
A crypto library for the Odin language

## Supported
This library offers various algorithms available in either native Odin or via bindings to the [Botan](https://botan.randombit.net/) crypto library.
Please see the chart below for the options.  
**Note:** All crypto hash algorithms, offered by [Botan\'s FFI](https://botan.randombit.net/handbook/api_ref/hash.html), have been added.

## Hashing algorithms
| Algorithm                                                                                                    | Odin             | Botan                |
|:-------------------------------------------------------------------------------------------------------------|:-----------------|:---------------------|
| [BLAKE](https://web.archive.org/web/20190915215948/https://131002.net/blake)                                 | ✔️ |                      |
| [BLAKE2B](https://datatracker.ietf.org/doc/html/rfc7693)                                                     | ✔️ | ✔️     |
| [BLAKE2S](https://datatracker.ietf.org/doc/html/rfc7693)                                                     | ✔️ |                      |
| [GOST](https://datatracker.ietf.org/doc/html/rfc5831)                                                        | ✔️ | ✔️     |
| [Grøstl](http://www.groestl.info/Groestl.zip)                                                                | ✔️ |                      |
| [HAVAL](https://web.archive.org/web/20150111210116/http://labs.calyptix.com/haval.php)                       | ✔️ |                      |
| [JH](https://www3.ntu.edu.sg/home/wuhj/research/jh/index.html)                                               | ✔️ |                      |
| [Keccak](https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf)                                           | ✔️ | ✔️     |
| [MD2](https://datatracker.ietf.org/doc/html/rfc1319)                                                         | ✔️ |                      |
| [MD4](https://datatracker.ietf.org/doc/html/rfc1320)                                                         | ✔️ | ✔️     |
| [MD5](https://datatracker.ietf.org/doc/html/rfc1321)                                                         | ✔️ | ✔️     |
| [RIPEMD](https://homes.esat.kuleuven.be/~bosselae/ripemd160.html)                                            | ✔️ | ✔️\*   |
| [SHA-1](https://datatracker.ietf.org/doc/html/rfc3174)                                                       | ✔️ | ✔️     |
| [SHA-2](https://csrc.nist.gov/csrc/media/publications/fips/180/2/archive/2002-08-01/documents/fips180-2.pdf) | ✔️ | ✔️     |
| [SHA-3](https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf)                                            | ✔️ | ✔️     |
| [SHAKE](https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf)                                            | ✔️ | ✔️     |
| [Skein](https://www.schneier.com/academic/skein/)                                                            |                  | ✔️\*\* |
| [SM3](https://datatracker.ietf.org/doc/html/draft-sca-cfrg-sm3-02)                                           | ✔️ | ✔️     |
| [Streebog](https://datatracker.ietf.org/doc/html/rfc6986)                                                    | ✔️ | ✔️     |
| [Tiger](https://www.cs.technion.ac.il/~biham/Reports/Tiger/)                                                 | ✔️ | ✔️     |
| [Tiger2](https://www.cs.technion.ac.il/~biham/Reports/Tiger/)                                                | ✔️ |                      |
| [Whirlpool](https://web.archive.org/web/20171129084214/http://www.larc.usp.br/~pbarreto/WhirlpoolPage.html)  | ✔️ | ✔️     |

\* Only `RIPEMD-160`  
\*\* Only `SKEIN-512`

#### High level API
Each hash algorithm contains a procedure group named `hash`, or if the algorithm provides more than one digest size `hash_<size>`\*\*\*.  
Included in these groups are four procedures.
* `hash_string` - Hash a given string and return the computed hash. Just calls `hash_bytes` internally
* `hash_bytes` - Hash a given byte slice and return the computed hash
* `hash_stream` - Takes a stream from io.Stream and returns the computed hash from it
* `hash_file` - Takes a file handle and returns the computed hash from it. A second optional boolean parameter controls if the file is streamed (this is the default) or read at once (set to true)

\*\*\* On some algorithms there is another part to the name, since they might offer control about additional parameters.  
For instance, `HAVAL` offers different sizes as well as three different round amounts.  
Computing a 256-bit hash with 3 rounds is therefore achieved by calling `haval.hash_256_3(...)`.

#### Low level API
The above mentioned procedures internally call three procedures: `init`, `update` and `final`.
You may also directly call them, if you wish.

#### Context system
The library uses a context system internally to be able to switch between Odin / Botan implementations freely.  
When an Odin implementation is available, it is the default.
You may change what is used during runtime by calling `foo.use_botan()` or `foo.use_odin()`.  
It is also possible to set this during compile time via `USE_BOTAN_LIB=true`.  
Internally a vtable is used to set the appropriate procedures when switching. This works for all the procedures mentioned in the APIs above.

#### Example
```odin
package crypto_example

// Import the desired package
import "core:crypto/md4"

main :: proc() {
    input := "foo"
    // Compute the hash via Odin implementation
    computed_hash := md4.hash(input)
    // Switch to Botan
    md4.use_botan()
    // Compute the hash via Botan bindings
    computed_hash_botan := md4.hash(input)
}
```
For example uses of all available algorithms, please see the tests within `tests/core/crypto`.

#### Thread safety
The crypto package is not thread-safe at the moment. This may change in the future.

### Disclaimer
The algorithms were ported out of curiosity and due to interest in the field.
We have not had any of the code verified by a third party or tested/fuzzed by any automatic means.
Whereever we were able to find official test vectors, those were used to verify the implementation.
We do not recommend using them in a production environment, without any additional testing and/or verification.

### ToDo
* Ciphers (Symmetric, Asymmetric)
* MACs (Message Authentication Code)
* CSPRNGs (Cryptographically Secure PseudoRandom Number Generator)
* KDFs (Key Derivation Function)
* KEAs (Key Exchange Algorithm)

### License
This library is made available under the BSD-3 license.