Update README.md

README.md

@@ -1,4 +1,7 @@
-### Passphrase Entropy Calculator
+## password-strength
+A password strength calculator based on [Dropbox's](https://github.com/dropbox) password strength estimator [zxcvbn](https://github.com/dropbox/zxcvbn).
+
+Also checks with haveibeenpwned API if a given password has been compromised.
 
 #### Build
 
@@ -9,14 +12,45 @@ make install
 
 #### Usage
 ```
-passphrase-entropy a passphrase
+  -password string
+    	a password
+  -word string
+    	used word
+  -pwned
+    	check with haveibeenpwned API if password has been seen before
+```
+
+#### Examples
+```
+password-strength -password "Tr0ub4dor&3," -word troubador
+
+Password:		Tr0ub4dor&3,
+Password strength:	1/4
+Guesses Log10:		5.041393
+
+Guess times
+100 / h:		1 months 	(throttled online attack)
+10  / s:		3 hours  	(unthrottled online attack)
+10k / s:		11 seconds	(offline attack, slow hash, many cores)
+10b / s:		< 1 second	(offline attack, slow hash, many cores)
 ```
 
-#### Output
 ```
-Evaluated string: a passphrase
+passphrase-entropy -password "correcthorsebatterystaple" -word "correct" -word "horse" -word "battery" -word "staple"
 
-Used character sets: Lowercase, Common Special Characters
+Password:		correcthorsebatterystaple
+Password strength:	4/4
+Guesses Log10:		12.008345
 
-Passphrase entropy: 71.4503557246425
+Guess times
+100 / h:		Centuries	(throttled online attack)
+10  / s:		Centuries	(unthrottled online attack)
+10k / s:		3 years  	(offline attack, slow hash, many cores)
+10b / s:		2 minutes	(offline attack, slow hash, many cores)
 ```
+
+#### Acknowledgements
+
+password-strength is based on [trustelem's](https://github.com/trustelem/zxcvbn) go implementation of [Dropbox's](https://github.com/dropbox) password strength estimator [zxcvbn](https://github.com/dropbox/zxcvbn).
+ 
+Also checks with haveibeenpwned API if a given password has been compromised with [a forked version](https://github.com/chaosbunker/haveibeenpwned) of [sinduvi87's haveibeenpwned](https://github.com/sinduvi87/haveibeenpwned).