Entropy

A Go-based program crafted to evaluate the strength of passwords through the analysis of entropy and semantic robustness.

Installation Instructions

entropy requires Go 1.18 or later to install successfully. Run the following command to install the latest version:

go install github.com/k4rkarov/entropy/cmd/entropy@latest

The -s flag relies on the zxcvbn-go library for semantic strength evaluation. The library will be automatically installed when you run entropy if it's not already available. Ensure your Go environment is properly configured to fetch and install dependencies.

Usage

entropy -h

This will display the help menu.

 ______       _                         
|  ____|     | |                        
| |__   _ __ | |_ _ __ ___  _ __  _   _ 
|  __| | '_ \| __| '__/ _ \| '_ \| | | |
| |____| | | | |_| | | (_) | |_) | |_| |
|______|_| |_|\__|_|  \___/| .__/ \__, |
                           | |     __/ |
                           |_|    |___/ 
 
       by k4rkarov (v2.0)

Usage:
  entropy <option> <password> [criteria] [-L <file>] [-v]

Options:
  -p       Calculate Password Entropy
  -pc      Calculate Entropy based on specified criteria
  -s       Evaluate password's semantic strength

Criteria (for -pc option):
  length  The number of characters in the password
  lc      lowercase characters: (a-z)
  uc      uppercase characters: (A-Z)
  d       digits: (0-9)
  s       special characters: !@#$%^&*()
  sp      additional special characters: ~-_=+[{]}|;:'",<.>/?
  spc     space (' ')

Output:
  -v      Increase verbosity level
  -L      Specify a file with a list of passwords

Examples:
  entropy -p password123
  entropy -p 'Pass@2#@!' -v
  entropy -pc 14 lc uc d
  entropy -s Pass@123 -v
  entropy -s -L passwords.txt

Running entropy

Calculate Password Entropy

$ entropy -p mypassword
Entropy: 47.00 bits

From a list

$ entropy -p -L list.txt 
password123 - Entropy: 56.87 bits
qwerty - Entropy: 28.20 bits
aloha@2024 - Entropy: 55.24 bits
impossible for you to know - Entropy: 123.63 bits

Adding verbosity

$ entropy -p mypassword -v
Entropy: 47.00 bits
Charset Size: 26
Length: 10

Lower Case Latin Alphabet (a-z)


$ entropy -p -L list.txt -v
password123 - Entropy: 56.87 bits
Charset Size: 36
Length: 11

Lower Case Latin Alphabet (a-z)
Numbers (0-9)

qwerty - Entropy: 28.20 bits
Charset Size: 26
Length: 6

Lower Case Latin Alphabet (a-z)

aloha@2024 - Entropy: 55.24 bits
Charset Size: 46
Length: 10

Lower Case Latin Alphabet (a-z)
Numbers (0-9)
Symbols (!@#$%()^&*)

impossible for you to know - Entropy: 123.63 bits
Charset Size: 27
Length: 26

Lower Case Latin Alphabet (a-z)
Space (' ')

Calculate Entropy Based on Data Criteria

$ entropy -pc 14 lc uc d
Entropy: 83.36 bits

Calculate Password's Semantic Strength

The -s option evaluates the semantic strength of the password using the zxcvbn-go library. Additionally, you can customize the list of common words by editing the common_words.txt file. You can add words from other languages or modify the list as needed. Ensure these modifications are made before compiling the Go program.

$ entropy -s Pass@123
Semantically weak.

$ entropy -s 'Ash&r$%D6D!@#18723'
PROBABLY NOT semantically weak

From a list

$ entropy -s -L list.txt 
password123 - Semantically weak.
qwerty - Semantically weak.
aloha@2024 - Semantically weak.
impossible for you to know - PROBABLY NOT semantically weak

Adding verbosity

$ entropy -s Pass@123 -v
Pass@123 - Semantically weak
Password is semantically weak according to zxcvbn.
Password contains a numeric sequence.
Password has a common word.

$ entropy -s -L list.txt -v
password123 - Semantically weak
Password is semantically weak according to zxcvbn.
Password contains a numeric sequence.
Password has a common word.
qwerty - Semantically weak
Password is semantically weak according to zxcvbn.
Password has a common word.
aloha@2024 - Semantically weak
Password is semantically weak according to zxcvbn.
Password has a common word.
Password has a year pattern.
impossible for you to know - PROBABLY NOT semantically weak

Notes

• If your password contains any special characters, enclose the entire password in single quotes to avoid issues with the program. Special characters include: !@#$%^&*(), \~-_=+[{]}|;:,<.>/?, and spaces.

For any issues or feature requests, please open an issue on the GitHub repository.

Enjoy using Entropy to secure your passwords!