Make crate publishable (#18)

* Add About section to README

* Expand package description in Cargo.toml

* Rename rust-secp256k1 -> secp256k1

* Make NULL_LABEL const public

Cargo.toml

@@ -1,7 +1,14 @@
 [package]
 name = "silentpayments"
 version = "0.1.0"
+authors = "Cygnet <cygnet3@proton.me>"
 edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "A library to add silent payments support to wallets"
+homepage = "https://github.com/cygnet3/rust-silentpayments"
+repository = "https://github.com/cygnet3/rust-silentpayments"
+keywords = ["bitcoin", "secp256k1"]
+readme = "README.md"
 
 [lib]
 name = "silentpayments"

README.md

@@ -2,8 +2,15 @@
 
 A rust implementation of BIP352: Silent Payments.
 
-Although this library passes all the tests provided in the silent payment BIP,
-it is still very new, so be careful when using this with real funds.
+## About
+
+**Warning: this crate is still new and is my first project doing elliptic curve cryptography!
+Even though it passes the tests provided in the official silent payments BIP,
+review it carefully before using this with mainnet funds.**
+
+This library supports creating and sending to silent payment addresses,
+building on [`secp256k1`](https://docs.rs/secp256k1/latest/secp256k1)
+`PublicKey` and `SecretKey` structs for the interface.
 
 There are two parts to this library: a sender part and a recipient part.
 

src/receiving.rs

@@ -13,7 +13,7 @@ use secp256k1::{Parity, PublicKey, Scalar, Secp256k1, SecretKey, XOnlyPublicKey}
 
 use crate::Result;
 
-pub(crate) const NULL_LABEL: Label = Label { s: Scalar::ZERO };
+pub const NULL_LABEL: Label = Label { s: Scalar::ZERO };
 
 #[derive(Eq, PartialEq, Clone)]
 pub struct Label {