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+## Shared-key authenticated encryption
+
+> **See also**: [Libsodium's documentation on its shared-key authenticated encryption features](https://download.libsodium.org/doc/secret-key_cryptography/secretbox).
+
+### crypto_secretbox
+
+Shared-key authenticated encryption.
+
+**Parameters and their respective types**:
+
+1. `{string|Buffer}` Plaintext
+2. `{string|Buffer}` nonce (must be 24 bytes)
+3. `{CryptographyKey}` key
+
+Returns a `Promise` that resolves to a `Buffer`.
+
+### crypto_secretbox_open
+
+Shared-key authenticated decryption.
+
+**Parameters and their respective types**:
+
+1. `{string|Buffer}` Ciphertext
+2. `{string|Buffer}` nonce (must be 24 bytes)
+3. `{CryptographyKey}` key
+
+Returns a `Promise` that resolves to a `Buffer`.
+Throws a `SodiumError` on decryption failure.
+
+### crypto_secretbox_keygen
+
+Returns a `CryptographyKey` object containing a key appropriate
+for the `crypto_secretbox` API.
+
+### Example for crypto_secretbox
+
+```javascript
+const { SodiumPlus } = require('sodium-plus');
+let sodium;
+
+(async function () {
+    if (!sodium) sodium = await SodiumPlus.auto();
+    let plaintext = 'Your message goes here';
+    let key = await sodium.crypto_secretbox_keygen();
+    let nonce = await sodium.randombytes_buf(24);
+    let ciphertext = await sodium.crypto_secretbox(
+        plaintext,
+        nonce,
+        key    
+    );
+
+    console.log(ciphertext.toString('hex'));
+
+    let decrypted = await sodium.crypto_secretbox_open(
+        ciphertext,
+        nonce,
+        key
+    );
+
+    console.log(decrypted.toString());
+})();
+```