bun.sh/docs/api/hashing.md

{% callout %}

Bun implements the createHash and createHmac functions from node:crypto in addition to the Bun-native APIs documented below.

{% /callout %}

Bun.hash

Bun.hash is a collection of utilities for non-cryptographic hashing. Non-cryptographic hashing algorithms are optimized for speed of computation over collision-resistance or security.

The standard Bun.hash functions uses Wyhash to generate a 64-bit hash from an input of arbitrary size.

Bun.hash("some data here");
// 976213160445840

The input can be a string, TypedArray, DataView, ArrayBuffer, or SharedArrayBuffer.

const arr = new Uint8Array([1, 2, 3, 4]);

Bun.hash("some data here");
Bun.hash(arr);
Bun.hash(arr.buffer);
Bun.hash(new DataView(arr.buffer));

Optionally, an integer seed can be specified as the second parameter.

Bun.hash("some data here", 1234);
// 1173484059023252

Additional hashing algorithms are available as properties on Bun.hash. The API is the same for each.

Bun.hash.wyhash("data", 1234); // equivalent to Bun.hash()
Bun.hash.crc32("data", 1234);
Bun.hash.adler32("data", 1234);
Bun.hash.cityHash32("data", 1234);
Bun.hash.cityHash64("data", 1234);
Bun.hash.murmur32v3("data", 1234);
Bun.hash.murmur64v2("data", 1234);

Bun.CryptoHasher

Bun.CryptoHasher is a general-purpose utility class that lets you incrementally compute a hash of string or binary data using a range of cryptographic hash algorithms. The following algorithms are supported:

• "blake2b256"
• "md4"
• "md5"
• "ripemd160"
• "sha1"
• "sha224"
• "sha256"
• "sha384"
• "sha512"
• "sha512-256"

const hasher = new Bun.CryptoHasher("sha256");
hasher.update("hello world");
hasher.digest();
// Uint8Array(32) [ <byte>, <byte>, ... ]

Once initialized, data can be incrementally fed to to the hasher using .update(). This method accepts string, TypedArray, and ArrayBuffer.

const hasher = new Bun.CryptoHasher();

hasher.update("hello world");
hasher.update(new Uint8Array([1, 2, 3]));
hasher.update(new ArrayBuffer(10));

If a string is passed, an optional second parameter can be used to specify the encoding (default 'utf-8'). The following encodings are supported:

{% table %}

---

• Binary encodings
• "base64" "base64url" "hex" "binary"

---

• Character encodings
• "utf8" "utf-8" "utf16le" "latin1"

---

• Legacy character encodings
• "ascii" "binary" "ucs2" "ucs-2"

{% /table %}

hasher.update("hello world"); // defaults to utf8
hasher.update("hello world", "hex");
hasher.update("hello world", "base64");
hasher.update("hello world", "latin1");

After the data has been feed into the hasher, a final hash can be computed using .digest(). By default, this method returns a Uint8Array containing the hash.

const hasher = new Bun.CryptoHasher();
hasher.update("hello world");

hasher.digest();
// => Uint8Array(32) [ 185, 77, 39, 185, 147, ... ]

The .digest() method can optionally return the hash as a string. To do so, specify an encoding:

hasher.digest("base64");
// => "uU0nuZNNPgilLlLX2n2r+sSE7+N6U4DukIj3rOLvzek="

hasher.digest("hex");
// => "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9"

Alternatively, the method can write the hash into a pre-existing TypedArray instance. This may be desirable in some performance-sensitive applications.

const arr = new Uint8Array(32);

hasher.digest(arr);

console.log(arr);
// => Uint8Array(32) [ 185, 77, 39, 185, 147, ... ]