tiny.reticulum.hash

1const std = @import("std");23const Sha256 = std.crypto.hash.sha2.Sha256;45/// 32 bytes, the width of a complete SHA-256 digest, following Reticulum@1.5.06/// RNS/Identity.py:352.7pub const full_bytes: usize = 32;8/// 16 bytes, the width a destination hash and an identity hash take on the9/// wire, following Reticulum@1.5.0 RNS/Identity.py:362 and Reticulum@1.5.010/// RNS/Reticulum.py:148.11pub const truncated_bytes: usize = 16;12/// 10 bytes, the width a destination's announced name hash and a rotating key's13/// identifier take, following Reticulum@1.5.0 RNS/Identity.py:83.14pub const name_bytes: usize = 10;1516/// Returns the complete 32-byte SHA-256 digest of some bytes, following17/// Reticulum@1.5.0 RNS/Identity.py:352.18pub fn full(bytes: []const u8) [full_bytes]u8 {19    var hasher = Hasher.init();20    hasher.update(bytes);21    return hasher.finalFull();22}2324/// Returns the first 16 bytes of the SHA-256 digest of some bytes, following25/// Reticulum@1.5.0 RNS/Identity.py:362 and Reticulum@1.5.026/// RNS/Reticulum.py:148.27pub fn truncated(bytes: []const u8) [truncated_bytes]u8 {28    var hasher = Hasher.init();29    hasher.update(bytes);30    return hasher.finalTruncated();31}3233/// Returns the first 10 bytes of the SHA-256 digest of some bytes, following34/// Reticulum@1.5.0 RNS/Identity.py:83 and Reticulum@1.5.035/// RNS/Destination.py:120.36pub fn name(bytes: []const u8) [name_bytes]u8 {37    var hasher = Hasher.init();38    hasher.update(bytes);39    return hasher.finalName();40}4142/// A SHA-256 state that takes its input in pieces and then gives any of the43/// three widths. Reticulum hashes joined transcripts, so a caller feeds the44/// pieces in turn and needs no buffer holding them all at once. Taking a digest45/// works on a copy of the state, so one hasher gives more than one width.46pub const Hasher = struct {47    state: Sha256,4849    pub fn init() Hasher {50        return .{ .state = Sha256.init(.{}) };51    }5253    pub fn update(self: *Hasher, bytes: []const u8) void {54        self.state.update(bytes);55    }5657    pub fn finalFull(self: Hasher) [full_bytes]u8 {58        var state = self.state;59        var result: [full_bytes]u8 = undefined;60        state.final(&result);61        return result;62    }6364    pub fn finalTruncated(self: Hasher) [truncated_bytes]u8 {65        const result = self.finalFull();66        return result[0..truncated_bytes].*;67    }6869    pub fn finalName(self: Hasher) [name_bytes]u8 {70        const result = self.finalFull();71        return result[0..name_bytes].*;72    }73};

1pub const hash = @import("hash.zig");