1 unstable release

0.1.0 Nov 10, 2023

#563 in Cryptography

Custom license

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Rust CLI Password Generator


This Project is a secure CLI password generator written in rust.
This generates a secure password with three different strategies including Random, Memorable words, and Pin Number along with shannon entropy and an intuitive password strength.
Lots of other configurations can be passed through to make it harder to be cracked. See below for more info.

Build and Run Instructions


  • First make sure you have the rust toolchain installed using rustup.
  • You can build the binary by running cargo build --release to build the project.
  • You can run the project by running the output binary ./target/release/spg.
  • Optional: You can copy and paste ./target/release/spg into your /usr/local/bin/ if you are on the UNIX based environment. Then just run spg.

Usage Instructions

Usage: spg [OPTIONS]

  -l, --length <LENGTH>
          Password length to be generated [default: 8]
  -g, --gen-type <GEN_TYPE>
          Password generation mechanism to be used [default: random] [possible values: random, pin, memorable]
  -n, --use-numbers
          Whether to use numbers in password
  -s, --use-symbols
          Whether to use special symbols in password
  -c, --use-capitals
          Whether to use capitalized letters in password
  -k, --capitalize-memorable-words
          Whether to capitalize generated words by chance
  -t, --capitalize-memorable-first-letter
          Whether to capitalize the first letter of generated words by chance
  -w, --words-count <WORDS_COUNT>
          The number of words included in memorable password [default: 5]
          Run in insecure mode. The output can be redirected or piped to files or non terminal environments
  -h, --help
          Print help
  -V, --version
          Print version

An example output would be as follows for spg -n -s -c -l 19 prompt:

Shannon entropy: 118.35
Strength: 100.00
Hit Enter to exit

Or we can have a memorable password with 4 words in it by running spg -g memorable -w 4 prompt:

Shannon entropy: 51.70
Strength: 66.67
Hit Enter to exit

Security Perspective

Data Protection

  • Secrecy crate has been used to Zeroise the memory. This crates guarantees that the memory will be freed.
  • It has been made sure that Secret types won't log anywhere by chance as they are protected by Secret type.
  • Running this program on a non-tty environment has been prohibited to prevent logging non-deliberately or letting malicious softwares sniff the generated password.
  • The output will be dismissed and overwritten after a timeout or any SIG from the OS.

Password Generation

  • Arbitrary sampling from uniform distribution has been used in random strategy to mitigate the timing attack.
  • EFF diceware list of words embedded in the binary to preserve integrity.

Development Perspective

Project Structure

This Project has three parts including main,cli,password_generator. Strategy pattern has been used in password_generator, to generate Random,Memorable, and Pin passwords. There is an assets directory which holds the EFF word list for diceware generation.


  • Run tests by running cargo test to run through the test cases.

Vulnerabilities and Mitigation

This code is not using mlock and/or mprotect to prevent the os from dumping the data into disk on various scenarios on OS.


  • Write more tests with more coverage.
  • More tests should be implemented in the future. Including security tests.
  • Use Bolero along with a fuzzy engine to produce arbitrary configs for pass generators.
  • Implement mlock/mprotect to protect the memory.


MIT License.


Feel free to enhance this project by forking it and creating PRs.
Leave a star if you find it useful.


~179K SLoC