zig/lib/std/rand/Gimli.zig
Ominitay c1a5ff34f3 std.rand: Refactor Random interface
These changes have been made to resolve issue #10037. The `Random`
interface was implemented in such a way that causes significant slowdown
when calling the `fill` function of the rng used.

The `Random` interface is no longer stored in a field of the rng, and is
instead returned by the child function `random()` of the rng. This
avoids the performance issues caused by the interface.
2021-10-27 16:07:48 -04:00

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Zig

//! CSPRNG
const std = @import("std");
const Random = std.rand.Random;
const mem = std.mem;
const Gimli = @This();
state: std.crypto.core.Gimli,
pub const secret_seed_length = 32;
/// The seed must be uniform, secret and `secret_seed_length` bytes long.
pub fn init(secret_seed: [secret_seed_length]u8) Gimli {
var initial_state: [std.crypto.core.Gimli.BLOCKBYTES]u8 = undefined;
mem.copy(u8, initial_state[0..secret_seed_length], &secret_seed);
mem.set(u8, initial_state[secret_seed_length..], 0);
var self = Gimli{
.state = std.crypto.core.Gimli.init(initial_state),
};
return self;
}
pub fn random(self: *Gimli) Random {
return Random.init(self);
}
pub fn fill(self: *Gimli, buf: []u8) void {
if (buf.len != 0) {
self.state.squeeze(buf);
} else {
self.state.permute();
}
mem.set(u8, self.state.toSlice()[0..std.crypto.core.Gimli.RATE], 0);
}