init

README.md

@@ -0,0 +1,74 @@
+# 🔮 Sage
+**Sage** is a lightweight cryptographic library built with Rust that layers [age](https://github.com/FiloSottile/age) encryption and [minisign](https://jedisct1.github.io/minisign/) signatures to enable **signed encryption** — ensuring both confidentiality **and** authenticity.
+
+Sage signs a message before encryption and again after encryption, verifying both layers on decryption. This offers **end-to-end message integrity, trust, and non-repudiation**.
+
+## 🚀 Features
+- 🔐 Encryption with age
+- ✍️  Dual minisign signatures (before and after encryption)
+- ✅ Signature verification on both layers during decryption
+- 📦 Easy key serialization and identity management
+
+## 🌱 Getting Started
+### Generate a New Identity
+
+```rust
+let id = sage::Identity::new();
+let persona = id.public();
+```
+
+- `Identity`: holds your private encryption and signing keys.
+- `Persona`: a tuple of `(age_public_key, minisign_public_key)` for sharing public keys.
+
+### Encrypt and Sign
+
+```rust
+let message = b"Hello, secure world!";
+let recipient = persona.enc_key().unwrap(); // Recipient's age public key
+
+let ciphertext = id.encrypt(message, &recipient);
+```
+
+### Verify and Decrypt
+
+```rust
+let sender_pk = persona.sign_key().unwrap(); // Sender's minisign public key
+
+match id.decrypt(&ciphertext, &sender_pk) {
+    Ok(msg) => {
+        println!("Decrypted: {}", String::from_utf8_lossy(&msg.payload));
+        println!("Signed at timestamp: {}", msg.timestamp);
+    }
+    Err(err) => eprintln!("Failed to decrypt: {:?}", err),
+}
+```
+
+## 📁 Saving & Loading Identities
+
+```rust
+id.save("my_keys/");
+
+let loaded = sage::Identity::try_load("my_keys/").unwrap();
+```
+
+- Saves two files: `age.key` and `sign.key`
+
+## 🔍 How It Works
+
+### Encryption Flow
+
+1. **Sign the plaintext** with minisign and add meta information (timestamp)
+2. **Encrypt** the signed payload using age
+3. **Sign the encrypted blob** with minisign again
+
+### Decryption Flow
+
+1. **Verify the outer signature** (authenticity of ciphertext)
+2. **Decrypt** using the age identity
+3. **Verify the inner signature** (authenticity of plaintext)
+4. **Extract** message and timestamp
+
+## 🙏 Credits
+
+- [age](https://github.com/FiloSottile/age) by Filippo Valsorda
+- [minisign](https://jedisct1.github.io/minisign/) by Frank Denis (jedisct1)