Documentation

baml.crypto.Sha256

SHA-256, the 256-bit member of the SHA-2 family (FIPS 180-4).

Reference version

Signature

class baml.crypto.Sha256

SHA-256, the 256-bit member of the SHA-2 family (FIPS 180-4).

Hashing is incremental. Feed the message in with update, in as many pieces as convenient, then read the 32-byte digest with finish:

let h = baml.crypto.Sha256.new();
h.update("hello".to_utf8());
h.update(" world".to_utf8());
h.finish().to_hex()  // b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9

A Sha256 is a handle onto hasher state, not a value. Two references to the same hasher feed the same digest, and update from separate spawn fibers is serialized rather than racing. Use a fresh Sha256.new() per message.

SHA-256 is a plain hash, not a keyed one. It authenticates nothing on its own: anyone can recompute the digest of a message they can guess. Do not use it to check that a message came from who you think, and do not hash passwords with it.

Source:<builtin>/baml/ns_crypto/sha2.bamlbytes 933–2111

Fields

_state

$rust_type

Opaque, runtime-owned hasher state: the SHA-256 compression state and the buffered tail of the message so far.

Static methods

function

new

() -> baml.crypto.Sha256 throws never

Creates a hasher with no data fed into it yet. Calling finish on it immediately returns the digest of the empty message.

Implementations

baml.Concrete for T

Source:<builtin>/baml/core.bamlbytes 763–795

baml.crypto.Hasher for baml.crypto.Sha256

Instance methods

function

finish

(self) -> uint8array throws never

Returns the 32-byte SHA-256 digest of everything fed in since the hasher was created or last finished.

This resets the hasher, so the next update starts a new message and calling finish twice in a row returns the digest of the empty message the second time.

function

update

(self, data: uint8array) -> null throws never

Feeds data into the hasher. Splitting a message across several update calls gives the same digest as one call with the whole message.

Source:<builtin>/baml/ns_crypto/sha2.bamlbytes 1335–2109