Entropy Calculator

Extensible batch password entropy calculator.

Usage: EntropyCalculator <input_file> [-c|-s|-l|-d|-u]
-c: Per-character Shannon entropy mode
-s: Shannon entropy mode
-l: Length-only mode
-d: Distinct-character mode
-u: LUDS mode

Overview

This utility will take a text files as input and calculate some score for each string contained in it, one per line. For example, given an input file like this:

123456
password
12345678
qwerty
123456789
12345
1234
111111
1234567
dragon
...

We'll get something like this:

password, score
123456, 15.5097750043269
password, 22
12345678, 24
qwerty, 15.5097750043269
123456789, 28.5293250129808
12345, 11.6096404744368
1234, 8
111111, 0
1234567, 19.6514844544032
dragon, 15.5097750043269
...

Scoring Modes

The program has a number of different scoring modes. Currently -s is the default:

• -c: Per-character Shannon entropy mode
• -s: Shannon entropy mode, equivalent to -c multiplied by the string length (-l).
• -l: Given a string of length n returns n.
• -d: Given a string containing k distinct characters (e.g. for aabc123 then k=6) returns k.
• -u: Given a string containing j LUDS character classes (lower, upper, digit, symbol) returns j.