jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

karlgluck

What's this all about?

Digital cryptography! This is a subject I've been interested in since taking a class with Prof. Fred Schneider back in college. Articles pop up on Hacker News fairly often that pique my interest and this technique is the result of one of them.

Specifically, this is about Lamport signatures. There are many signature algorithms (ECDSA and RSA are the most commonly used) but Lamport signatures are unique because they are formed using a hash function. Many cryptographers believe that this makes them resistant to attacks made possible by quantum computers.

How does a Lamport Signature work?

jozefg

import Control.Monad.State
import Control.Monad.Error
import Control.Applicative

type Sym = Int
data Term = Box Int
          | Star
          | Abs Term (Term -> Term)
          | App Term Term
          | Forall Term (Term -> Term)

lawrencejones

tell application "Chrome" to tell the active tab of its first window
    reload
end tell

jesperborgstrup

# MIT License
#
# Copyright (C) 2014 Jesper Borgstrup
# -------------------------------------------------------------------
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,

jesperborgstrup

# MIT License
#
# Copyright (C) 2014 Jesper Borgstrup
# -------------------------------------------------------------------
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,

karlgluck

Extensible Merkle Trees

I present a simple algorithm that lets one use an undetermined number of OTS's for the same public key at the expense of a larger signature. My scheme would allow at least 4.2 billion one-time signatures to be used with a single public key using today's technology.

Background

The Merkle signature scheme (MSS) is a well-known way to use a one-time signature (OTS) like the Lamport-Diffie OTS to create a public key cryptosystem. Briefly, one creates a hash tree of height h from 2^h OTS public keys leading to a root public key. To sign a message, one then simply creates a signature from one of the leaf OTS's as usual and provides evidence of its presence in the tree by giving the sequence of hashes that lead from it to the root public key of the MSS.

carols10cents

JavaScript to Rust Cheat Sheet

The goal of this is to have an easily-scannable reference for the most common syntax idioms in JavaScript and Rust so that programmers most comfortable with JavaScript can quickly get through the syntax differences and feel like they could read and write basic Rust programs.

What do you think? Does this meet its goal? If not, why not?

Variables

JavaScript:

gallais

{-# OPTIONS --copatterns #-}

module UntypedLambda where

open import Size
open import Function

mutual

  data Delay (A : Set) (i : Size) : Set where

pascaldekloe

// This is free and unencumbered software released into the public domain.

// Marshals a string to an Uint8Array.
function encodeUTF8(s) {
	var i = 0, bytes = new Uint8Array(s.length * 4);
	for (var ci = 0; ci != s.length; ci++) {
		var c = s.charCodeAt(ci);
		if (c < 128) {
			bytes[i++] = c;
			continue;