SkyN9ne SkyN9ne

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Don't use VPN services.

No, seriously, don't. You're probably reading this because you've asked what VPN service to use, and this is the answer.

Note: The content in this post does not apply to using VPN for their intended purpose; that is, as a virtual private (internal) network. It only applies to using it as a glorified proxy, which is what every third-party "VPN provider" does.

A Russian translation of this article can be found here, contributed by Timur Demin.
A Turkish translation can be found here, contributed by agyild.
There's also this article about VPN services, which is honestly better written (and has more cat pictures!) than my article.

HTTPShame

A shame-list of popular or important websites which have not yet deployed HTTPS certificates by default.

Sites which may involve the transmission of very sensitive data, such as health or banking information, are marked with an ❗ to signal they should deploy HTTPS-by-default as soon as possible. If you are a popular website (such as those on the Alexa Top 500 Global Sites) which finds itself on this list - and you want to be removed - you can visit Let's Encrypt about transitioning to HTTPS. It's easy, free, and will help you learn how to protect your customers/ readers!

List now outdated, removed until further notice.

Q: What is HTTPS?

	admin account info" filetype:log
	!Host=. intext:enc_UserPassword=* ext:pcf
	"# -FrontPage-" ext:pwd inurl:(service \| authors \| administrators \| users) "# -FrontPage-" inurl:service.pwd
	"AutoCreate=TRUE password=*"
	"http://:@www” domainname
	"index of/" "ws_ftp.ini" "parent directory"
	"liveice configuration file" ext:cfg -site:sourceforge.net
	"parent directory" +proftpdpasswd
	Duclassified" -site:duware.com "DUware All Rights reserved"
	duclassmate" -site:duware.com

	#!/usr/local/bin/python
	import os, sys, math, hmac, operator, time, random, urllib2, md5

	class AES(object):

	# Rijndael S-box
	sbox = [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67,
	0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59,
	0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7,
	0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1,