# Secret Contract Development Toolkit - Crypto Tools

⚠️ This package is a sub-package of the `secret-toolkit` package. Please see its crate page for more context.

This crate contains common cryptography tools used in the development of Secret Contracts
running on the Secret Network.

Note: It has a deep dependency tree and increases compilation times significantly.

Add the following to your `cargo.toml` file:

```toml
[dependencies]
secret-toolkit = { version = "0.10.1", features = ["crypto"] }
secret-toolkit-crypto = { version = "0.10.1", features = ["hash", "rand", "ecc-secp256k1"] }
```

## Example usage

```rust
# extern crate secret_toolkit_crypto;

# use secret_toolkit_crypto::{sha_256, ContractPrng, secp256k1::{PrivateKey, PublicKey, Signature}};
# use base64;
# use cosmwasm_std::{StdError, testing::mock_dependencies};

# fn main() -> Result<(), StdError> {
let deps = mock_dependencies();
let entropy: String = "secret".to_owned();
let prng_seed: Vec<u8> = sha_256(base64::encode(&entropy.clone()).as_bytes()).to_vec();

let mut rng = ContractPrng::new(&prng_seed, entropy.as_bytes());

let private_key: PrivateKey = PrivateKey::parse(&rng.rand_bytes())?;
let public_key: PublicKey = private_key.pubkey();

let message: &[u8] = b"message";
let signature: Signature = private_key.sign(message, deps.api);
# Ok(())
# }
```

### Cargo Features

- `["hash"]` - Provides an easy-to-use `sha256` function. Uses [sha2](https://crates.io/crates/sha2).
- `["rand"]` - Used to generate pseudo-random numbers. Uses [rand_chacha] and [rand_core].
- `["ecc-secp256k1"]` - Contains types and methods for working with secp256k1 keys and signatures,
  as well as standard constants for key sizes. Uses [secp256k1](https://crates.io/crates/secp256k1).