add an example to the documentation

1 files changed, 39 insertions, 0 deletions

diff --git a/README.md b/README.md
index d0a482a..6d0d492 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,45 @@ it to be secure.
 
 Use it at **your own risk** and if you know what you are doing!
 
+## Example Code
+
+```rust
+use hohibe::kem::HybridKem;
+
+const MAX_DEPTH: usize = 3;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut rng = rand::thread_rng();
+    let kem = HybridKem::new(MAX_DEPTH);
+    let (public_key, master_secret) = kem.setup(&mut rng)?;
+
+    // Encrypt for hibe.example.com
+    let ciphertext = kem.encrypt(&mut rng, &public_key, &["com", "example", "hibe"], b"GET /")?;
+
+    // Assume that the owner of example.com is given the secret key for their domain ...
+    let example_com = kem.generate_key(
+        &mut rng,
+        &public_key,
+        &master_secret,
+        &["com", "example"],
+    )?;
+    // ... and they can use that to derive the key for the subdomain
+    let secret_key = kem.derive_key(
+        &mut rng,
+        &public_key,
+        &example_com,
+        &["com", "example", "hibe"],
+    )?;
+
+    // Now we can decrypt
+    let plaintext = kem.decrypt(&public_key, &secret_key, &ciphertext)?;
+
+    assert_eq!(plaintext, b"GET /");
+
+    Ok(())
+}
+```
+
 ## License
 
 hohibe is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.