add edwards WIT example component & tests

to use the seed keeper and it's WIT, we'll need a consumer of the get_seed who will use it for signing.

So let's build an example using Ed25519 curve

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = [".", "crates/*"]
+members = [".", "crates/*", "examples/edwards-wit"]
 resolver = "2"
 
 [workspace.dependencies]

examples/edwards-wit/.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "rust-analyzer.check.overrideCommand": ["cargo", "component", "check", "--message-format=json"]
+}

examples/edwards-wit/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "edwards-wit"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+cargo-component-bindings = "0.5.0"
+ed25519-dalek = "2.1"
+
+[dev-dependencies]
+wasmtime = { version = "15", features = ['component-model'] }
+wasmtime-wasi = "15.0.0"
+thiserror = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+
+[package.metadata.component]
+package = "component:edwards-wit"
+
+[package.metadata.component.dependencies]
+
+[package.metadata.component.target.dependencies]
+"seed-keeper:wallet" = { path = "../../crates/seed-keeper-wit/wit" }  # directory containing the WIT package

examples/edwards-wit/README.md

@@ -0,0 +1,44 @@
+# Example Plugin
+
+Usign Edwards curve to sign a message and verify the signature.
+
+## Create a Plugin WIT Component
+
+1. Create a component using [`cargo component`](https://github.com/bytecodealliance/cargo-component):
+
+```bash
+cargo component new --reactor <name>
+```
+
+2. Import the seed keeper get seed interface
+
+```wit
+world yourworld {
+
+    import seed-keeper:wallet/[email protected];
+
+    // the rest of your WIT world
+    export operations;
+}
+```
+
+3. Add the path to the wallet wit file in your Cargo.toml. This is just the interface, not the implementation of it.
+
+```toml
+[package.metadata.component.target.dependencies]
+"seed-keeper:wallet" = { path = "../path/to/seed-keeper-wit/wit" }  # directory containing the WIT package
+```
+
+4. Export an interface which defines a `sign` func which takes a message and returns a signature.
+
+```wit
+/// WIT interface operations exported by yourworld 
+interface operations {
+    sign: func(message: list<u8>) -> list<u8>;
+    verify: func(message: list<u8>, signature: list<u8>) -> bool;
+}
+```
+
+## Compose
+
+Compose this plugin together with the `seed-keeper-wit` and the `seed-keeper-wit-ui` components.

examples/edwards-wit/src/lib.rs

@@ -0,0 +1,63 @@
+cargo_component_bindings::generate!();
+
+use bindings::exports::component::edwards_wit::operations::Guest;
+// use bindings::seed_keeper::wallet::seed_getter::get_seed;
+
+use ed25519_dalek::SECRET_KEY_LENGTH;
+use ed25519_dalek::{Signature, Signer, SigningKey};
+
+struct Component;
+
+impl Guest for Component {
+    /// Say hello!
+    /// sign: func(message: list<u8>) -> list<u8>;
+    fn sign(message: Vec<u8>) -> Result<Vec<u8>, String> {
+        let seed = [1u8; 32]; // get_seed()?;
+        let seed: [u8; SECRET_KEY_LENGTH] = seed
+            .clone()
+            .try_into()
+            .map_err(|_| format!("Seed length is not 32 bytes, got {}", seed.len()).to_owned())?;
+        let signer = SigningKey::from_bytes(&seed);
+        let signature: Signature = signer.sign(&message);
+        Ok(signature.to_bytes().to_vec())
+    }
+
+    /// Verify
+    /// verify: func(message: list<u8>, signature: list<u8>) -> bool;
+    fn verify(message: Vec<u8>, signature: Vec<u8>) -> Result<bool, String> {
+        let seed = [1u8; 32]; //  get_seed()?;
+        let seed: [u8; SECRET_KEY_LENGTH] = seed
+            .clone()
+            .try_into()
+            .map_err(|_| format!("Seed length is not 32 bytes, got {}", seed.len()).to_owned())?;
+        let signer = SigningKey::from_bytes(&seed);
+        let signature = Signature::from_bytes(
+            &(signature.clone().try_into().map_err(|_| {
+                format!("Signature length is not 64 bytes, got {}", signature.len()).to_owned()
+            })?),
+        );
+        Ok(signer.verify(&message, &signature).is_ok())
+    }
+}
+
+#[cfg(test)]
+mod test_edwards_wit {
+    use super::*;
+
+    fn assert_keypair(keypair: &SigningKey) -> bool {
+        let message: &[u8] = b"This is a test of the tsunami alert system.";
+        let signature: Signature = keypair.sign(message);
+        keypair.verify(message, &signature).is_ok()
+    }
+
+    #[test]
+    fn test_keypair_from_seed() {
+        let seed: [u8; 32] = [
+            0x9d, 0x61, 0xb1, 0x9d, 0xef, 0xfd, 0x5a, 0x60, 0xba, 0x84, 0x4a, 0xf4, 0x92, 0xec,
+            0x2c, 0xc4, 0x44, 0x49, 0xc5, 0x69, 0x34, 0x67, 0x2b, 0x6a, 0x2f, 0x8d, 0x1d, 0x7b,
+            0x10, 0xac, 0x39, 0x23,
+        ];
+        let keypair = SigningKey::from_bytes(&seed);
+        assert_keypair(&keypair);
+    }
+}