Initial concept and README

README.md

@@ -1,2 +1,97 @@
+
 # pword
+
 Generate secure passwords. 
+
+# Overview
+
+`pword` is a utility to generate strong passwords that are memorable. 
+
+```
+$ pword online
+amiable obvious abdomen vogue
+hexagon xerox collarbone syringes
+double walrus judiciary olympics
+enquirer mammal saltshaker guitar
+```
+
+It is based on the concept behind [XKCD 936](https://xkcd.com/936/) and [XKCD-password-generator](https://github.com/redacted/XKCD-password-generator). It makes use of [EFF's typo-tolerant wordlist](https://www.eff.org/deeplinks/2016/07/new-wordlists-random-passphrases) to provide live autocomplete.
+
+# Usage
+
+```
+$ pword help
+NAME:
+    pword - generate secure passwords
+
+USAGE:
+    greet command [options]
+
+COMMANDS:
+    help, h  Shows a list of commands or help for one command
+    online   Generates passwords for use on websites
+    offline  Generates passwords for use offline (laptops, encrypted drives)
+    crypto   Generates extremely secure passwords
+    recall   Utility with autocomplete to help you recall passwords
+
+GLOBAL OPTIONS:
+    --count NUM, -c NUM   Generates NUM passwords for you to choose from
+	--one, -1             Equivalent to -c 1
+    --stronger            Chooses from a list of 7,776 words
+```
+
+# Modes
+
+# Online
+
+This mode generates a 4-word password from the 1,296-word list. The number of possible combinations would be 
+
+```
+1,296⁴ = 2,821,109,907,456
+```
+
+If an attacker could brute-force passwords on a website at 1,000 requests/second (where he would definitely hit rate limits), it would take about
+
+```
+2,821,109,907,456 / 1000 / 60 / 60 / 24 / 365 = 89.46
+```
+
+years to crack it. This is secure enough for online websites.  
+
+# Offline
+
+This mode generates a 6-word password. This equates to
+
+```
+1,296⁶ = 4,738,381,338,321,616,896
+```
+
+possible combinations. With the MD5 hash and [8 Nvidia GTX 1080 GPUs](https://gist.github.com/epixoip/a83d38f412b4737e99bbef804a270c40) cracking the password would take about
+
+```
+4,738,381,338,321,616,896 / 25,000,000,000 / 60 / 60 / 24 / 365 = 6.010
+```
+
+years to crack. That would cost the attacker a lot of energy. If the password was hashed using SHA512 it would take about
+
+```
+4,738,381,338,321,616,896 / 1,100,000,000 / 60 / 60 / 24 / 365 = 136.6
+```
+
+years to crack. This is definitely secure enough for offline use (your laptop's password, encrypted drive)
+
+# Crypto
+
+This mode generates a 8-word password. There would be
+
+```
+1,296⁸ = 7,958,661,109,946,400,884,391,936
+```
+
+possible combinations, and would take about
+
+```
+7,958,661,109,946,400,884,391,936 / 1,100,000,000 / 60 / 60 / 24 / 365 = 229400000
+```
+
+years to crack. If someone were to sponsor 8000 Nvidia GTX 1080 GPUs, it will still take a huge number of years to crack.