ssz.zig

A Zig implementation of the SSZ serialization protocol.

This is meant to work with zig version 0.14.x.

Serialization

Use serialize to write a serialized object to a byte buffer.

Currently supported types:

• BitVector[N]
• uintN
• boolean
• structures
• optionals
• null
• Vector[N]
• tagged unions
• List[N]
• Bitlist[N]

Ziglang has the limitation that it's not possible to determine which union field is active without tags.

Deserialization

Use deserialize to turn a byte array containing a serialized payload, into an object.

deserialize does not allocate any new memory. Scalar values will be copied, and vector values use references to the serialized data. Make a copy of the data if you need to free the serialized payload. Future versions will include a version of deserialize that expects an allocator.

Supported types:

• uintN
• boolean
• structures
• strings
• BitVector[N]
• Vector[N]
• unions
• optionals
• List[N]
• Bitlist[N]

Merkelization (experimental)

Use tree_root_hash to calculate the root hash of an object.

Supported types:

• Bitvector[N]
• boolean
• uintN
• Vector[N]
• structures
• strings
• optionals
• unions
• List[N]
• Bitlist[N]

Using Custom Hash Functions

ssz.zig is hash-function agnostic. Pass your hasher as a type parameter:

const std = @import("std");
const ssz = @import("ssz.zig");

// Using SHA256 (from stdlib)
const Sha256 = std.crypto.hash.sha2.Sha256;
try ssz.hashTreeRoot(Sha256, MyType, value, &root, allocator);

// Using a custom hasher (must implement init/update/final API)
const MyHasher = ...; // Your hasher type
try ssz.hashTreeRoot(MyHasher, MyType, value, &root, allocator);

Required Hasher API:

pub const Options = struct {};
pub fn init(_: Options) Self;
pub fn update(self: *Self, data: []const u8) void;
pub fn final(self: *Self, out: *[Self.digest_length]u8) void; // out size matches 32 bytes for SSZ

Contributing

Simply create an issue or a PR.