k4rkarov / entropy

A Go program designed to calculate both the password entropy and its semantic strength.

Entropy

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

Installation Instructions

entropy requires go1.18 to install successfully. Run the following command to install the latest version:

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

Usage

entropy -h

This will display help menu.

 ______       _                         
|  ____|     | |                        
| |__   _ __ | |_ _ __ ___  _ __  _   _ 
|  __| | '_ \| __| '__/ _ \| '_ \| | | |
| |____| | | | |_| | | (_) | |_) | |_| |
|______|_| |_|\__|_|  \___/| .__/ \__, |
                           | |     __/ |
                           |_|    |___/ 
 
       by k4rkarov (v1.0)

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:

$ 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
Semantically weak:
Password contains a numeric sequence. 
Password has a common word.

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