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+## General-purpose cryptographic hash
+
+> **See also**: [Libsodium's documentation on its generic hashing features](https://download.libsodium.org/doc/hashing/generic_hashing).
+
+### crypto_generichash
+
+General-purpose cryptographic hash (powered by BLAKE2).
+
+**Parameters and their respective types**:
+
+1. `{Buffer}` message
+2. `{CryptographyKey|null}` key (optional)
+3. `{number}` output length (optional, defaults to 32)
+
+Returns a `Promise` that resolves to a `Buffer`.
+
+### crypto_generichash_keygen
+
+Returns a `CryptographyKey` object containing a key appropriate
+for the `crypto_generichash` API.
+
+### crypto_generichash_init
+
+Initialize a BLAKE2 hash context for stream hashing.
+
+**Parameters and their respective types**:
+
+1. `{CryptographyKey|null}` key (optional)
+2. `{number}` output length (optional, defaults to 32)
+
+Returns a `Promise` that resolves to... well, that depends on your backend.
+
+* sodium-native returns a `CryptoGenericHashWrap` object.
+* libsodium-wrappers returns a number (a buffer's memory address)
+
+### crypto_generichash_update
+
+Update the BLAKE2 hash state with a block of data.
+
+**Parameters and their respective types**:
+
+1. `{*}` hash state (see [crypto_generichash_init()](#crypto_generichash_init))
+2. `{string|Buffer}` message chunk
+
+Returns a `Promise` that resolves to `void`. Instead, `state` is updated in-place.
+
+### crypto_generichash_final
+
+Obtain the final BLAKE2 hash output.
+
+**Parameters and their respective types**:
+
+1. `{*}` hash state (see [crypto_generichash_init()](#crypto_generichash_init))
+2. `{number}` output length (optional, defaults to 32)
+
+Returns a `Promise` that resolves to a `Buffer`.
+
+### Example for crypto_generichash
+
+```javascript
+const { SodiumPlus } = require('sodium-plus');
+let sodium;
+
+(async function () {
+    if (!sodium) sodium = await SodiumPlus.auto();
+    let message = 'Any message can go here';
+    let hashed = await sodium.crypto_generichash(message);
+    console.log(hashed.toString('hex'));
+
+    let key = await sodium.crypto_generichash_keygen();
+    let hash2 = await sodium.crypto_generichash(message, key, 64);
+    let state = await sodium.crypto_generichash_init(key, 64);
+
+    await sodium.crypto_generichash_update(state, 'Any message ');
+    await sodium.crypto_generichash_update(state, 'can go here');
+    let hash3 = await sodium.crypto_generichash_final(state, 64);
+    if (!await sodium.sodium_memcmp(hash2, hash3)) {
+        throw new Error('Implementation is broken. You should never see this.');
+    }
+    console.log(hash2.toString('hex'));
+})();
+```