local blake2 = require'blake2'

A ffi binding of the BLAKE2 fast cryptographic hash.

API

In the table below, ? is either s, b, sp or bp for each variant of the BLAKE2 algorithm.

blake2.blake2?(s, [size], [key], [#out]) -> s blake2.blake2?(cdata, size, [key]) -> s	compute the hash of a string or a cdata buffer.
blake2.blake2?_digest([key, [#out] | opt_t]) -> digest	get an object/function that can consume multiple data chunks before returning the hash
digest[:update](s, [size]) digest[:update](cdata, size)	consume a data chunk
digest[:final]() -> s digest:final_to_buffer(buf) digest:length() -> n	finalize and get the hash finalize and write the hash to a buffer hash byte length
digest:reset()	prepare for another digestion

The hash is returned raw in a Lua string. To get it as hex use glue.tohex().

The optional key arg is for keyed hashing (up to 64 bytes for BLAKE2b, up to 32 bytes for BLAKE2s).

The optional #out arg is for reducing the length of the output hash.

The constructors blake2s_digest and blake2b_digest can take a table in place of the key arg in which more options can be specified:

• salt (’’): salt for randomized hashing (up to 16 bytes for BLAKE2b, up to 8 bytes for BLAKE2s).
• personal (’’): personalization string (up to 16 bytes for BLAKE2b, up to 8 bytes for BLAKE2s).
• fanout (1): fanout (0 to 255, 0 if unlimited, 1 in sequential mode).
• depth (1): maximal depth of tree (1 to 255, 255 if unlimited, 1 in sequential mode).
• leaf_length (0): maximal byte length of leaf (0 to 2^32-1, 0 if unlimited or in sequential mode).
• node_offset (0): node offset (0 to 2^64-1 for BLAKE2b, 0 to 2^48-1 for BLAKE2s, 0 for the first, leftmost, leaf, or in sequential mode).
• node_depth (0): node depth (0 to 255, 0 for leaves, or in sequential mode).
• inner_length (0): inner digest length (0 to 64 for BLAKE2b, 0 to 32 for BLAKE2s, 0 in sequential mode).
• key: key string for keyed hashing (up to 64 bytes for BLAKE2b, up to 32 bytes for BLAKE2s).
• hash_length: optional, for reducing the length of the output hash.

NOTE: the salt and personal options are zero-padded so 'foo' is the same value as 'foo\0' or 'foo\0\0' with them (not so with key).

See section 2.10 in BLAKE2 specification for comprehensive review of tree hashing.

Last updated: 5 years ago | Edit on GitHub