Franck Verrot franckverrot

Zero knowledge databases

The idea

The idea is to provide a database as a service to end users in such a way that no one except the user herself can access the data, not even the hosting provider or the database administrator.

Advantages

A privacy- and/or security-conscious user will have more trust in such a setup.
The service provider cannot be coerced to release the data they were trusted with, and he cannot be held responsible for the content he is storing.

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

Install Dependencies

npm install --save jquery popper.js tether [email protected] font-awesome // popper.js for bootstrap 4 dependency

Copy font-awesome fonts to assets/static/fonts folder

cp -r assets/node_modules/font-awesome/fonts to assets/static

These are the Kickstarter Engineering and Data role definitions for both teams.

Technical	Data	People
Junior Software Engineer
Software Engineer	Data Analyst
Senior Software Engineer	Data Scientist	Engineering Manager
Staff Engineer	VP of Data	Engineering Director
Principal Engineer		CTO

	var 0..9: POS_1;
	var 0..9: POS_2;
	var 0..9: POS_3;


	constraint (
	% 682 one correct and well placed
	(
	(POS_1 == 6 /\ (not (POS_2 in {8, 2})) /\ (not (POS_3 in {8, 2})))
	\/ (POS_2 == 8 /\ (not (POS_1 in {6, 2})) /\ (not (POS_3 in {6, 2})))

	solution(POS_1, POS_2, POS_3) :-
	member(POS_1, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
	member(POS_2, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
	member(POS_3, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),

	/* 682 one correct and well placed */
	( POS_1 = 6; POS_2 = 8; POS_3 = 2),

	/* 614 one correct not well placed */
	(

	/*
	* This program is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	*/

	#include <arpa/inet.h>
	#include <linux/if_packet.h>
	#include <stdio.h>

	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

	require 'fiddle'
	require 'minitest/autorun'

	class RubyVM
	class InstructionSequence
	address = Fiddle::Handle::DEFAULT['rb_iseq_load']
	func = Fiddle::Function.new(address, [Fiddle::TYPE_VOIDP] * 3, Fiddle::TYPE_VOIDP)

	define_singleton_method(:load) do \|data, parent = nil, opt = nil\|
	func.call(Fiddle.dlwrap(data), parent, opt).to_value

	defmodule HttpRequester do
	use GenServer

	def start_link(_) do
	GenServer.start_link(__MODULE__, nil, [])
	end

	def fetch(server, url) do
	# Don't use cast: http://blog.elixirsips.com/2014/07/16/errata-dont-use-cast-in-a-poolboy-transaction/
	timeout_ms = 10_000