#password #strength #bcrypt #generate #score


This crate provides useful tools to generate multiple readable passwords, as well as analyze and score them

22 releases (stable)

3.1.8 Sep 19, 2021
3.1.7 Apr 22, 2021
3.1.4 Mar 11, 2021
3.1.3 Jul 29, 2020
0.3.1 Sep 7, 2018

#19 in Algorithms

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5,941 downloads per month

MIT license

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This crate provides useful tools to generate multiple readable passwords, as well as analyze and score them.


PasswordGenerator can be used for generating passwords which consist optional numbers, lowercase letters, uppercase letters, symbols and spaces.

extern crate passwords;

use passwords::PasswordGenerator;

let pg = PasswordGenerator {
       length: 8,
       numbers: true,
       lowercase_letters: true,
       uppercase_letters: true,
       symbols: true,
       spaces: true,
       exclude_similar_characters: false,
       strict: true,

println!("{}", pg.generate_one().unwrap());
println!("{:?}", pg.generate(5).unwrap());

It also has a fluent interface.

extern crate passwords;

use passwords::PasswordGenerator;

let pg = PasswordGenerator::new().length(8).numbers(true).lowercase_letters(true).uppercase_letters(true).symbols(true).spaces(true).exclude_similar_characters(true).strict(true);

println!("{}", pg.generate_one().unwrap());
println!("{:?}", pg.generate(5).unwrap());

The generate method has been optimized for multiple generation. Don't reuse the generate_one method to generate multiple passwords. If the count of passwords can't be determined, use the try_iter method to create a PasswordGeneratorIter instance which implements the Iterator trait and can re-generate passwords more efficiently.

extern crate passwords;

use passwords::PasswordGenerator;

let pgi = PasswordGenerator::new().try_iter().unwrap();

println!("{}", pgi.generate_one());
println!("{:?}", pgi.generate(5));
extern crate passwords;

use passwords::PasswordGenerator;

let mut pgi = PasswordGenerator::new().try_iter().unwrap();

println!("{}", pgi.next().unwrap());
println!("{}", pgi.next().unwrap());


To enable hashing functions, you need to enable the crypto feature.

version = "*"
features = ["crypto"]

Then, bcrypt, identify_bcrypt, bcrypt_format, identify_bcrypt_format, get_password_with_null_terminated_byte and gen_salt functions in the hasher module are available.

extern crate passwords;
use passwords::hasher;

let salt = hasher::gen_salt();
let hashed = hasher::bcrypt(10, &salt, "password\0").unwrap();
assert!(hasher::identify_bcrypt(10, &salt, "password\0", &hashed).unwrap());


The analyze function in the analyzer module can be used to create a AnalyzedPassword instance which contains some information about the input password.

Typically, we don't want our readable password to contain control characters like BS, LF, CR, etc. Before the analyzer analyzes a password, it filters the password in order to remove its control characters. And after analyzing, the analyzer will return the filtered password. Therefore, you can use this analyzer as a password guard before you store the input password (or generally hash it first and then store) to your database.

extern crate passwords;

use passwords::analyzer;

let password = "ZYX[$BCkQB中文}%A_3456]  H(\rg";

let analyzed = analyzer::analyze(password);

assert_eq!("ZYX[$BCkQB中文}%A_3456]  H(g", analyzed.password()); // "\r" was filtered
assert_eq!(26, analyzed.length()); // Characters' length, instead of that of UTF-8 bytes
assert_eq!(2, analyzed.spaces_count()); // Two spaces between "]" and "H"
assert_eq!(4, analyzed.numbers_count()); // Numbers are "3456"
assert_eq!(2, analyzed.lowercase_letters_count()); // Lowercase letters are "k" and "g"
assert_eq!(9, analyzed.uppercase_letters_count()); // Uppercase letters are "ZYX", "BC", "QB", "A" and "H"
assert_eq!(7, analyzed.symbols_count()); // Symbols are "[$", "}%", "_", "]" and "("
assert_eq!(2, analyzed.other_characters_count()); // Other characters are "中文". These characters are usually not included on the rainbow table.
assert_eq!(2, analyzed.consecutive_count()); // Consecutive repeated characters are "  " (two spaces)
assert_eq!(2, analyzed.non_consecutive_count()); // Non-consecutive repeated characters are "B" (appears twice)
assert_eq!(7, analyzed.progressive_count()); // Progressive characters are "ZYX" and "3456". "BC" is not counted, because its length is only 2, not three or more.

You can also check whether a password is too simple and dangerous to use, by looking up a common passwords table. If you want to do that, you need to enable the common-password feature.

version = "*"
features = ["common-password"]

Then, the is_common_password function in analyzer module and the is_common method of a AnalyzedPassword instance are available.

You should notice that after you enable the common-password feature, the time for compiling increases dramatically, because the common passwords table will be compiled into the executable binary file as a hardcode array.


After analyzing a password, you can use the score function in the scorer module to score it.

extern crate passwords;

use passwords::analyzer;
use passwords::scorer;

assert_eq!(62f64, scorer::score(&analyzer::analyze("kq4zpz13")));
assert_eq!(100f64, scorer::score(&analyzer::analyze("ZYX[$BCkQB中文}%A_3456]  H(\rg")));

if cfg!(feature = "common-password") {
    assert_eq!(11.2f64, scorer::score(&analyzer::analyze("feelings"))); // "feelings" is common, so the score is punitively the original divided by 5
} else {
    assert_eq!(56f64, scorer::score(&analyzer::analyze("feelings")));

A password whose score is,

  • 0 ~ 20 is very dangerous (may be cracked within few seconds)
  • 20 ~ 40 is dangerous
  • 40 ~ 60 is very weak
  • 60 ~ 80 is weak
  • 80 ~ 90 is good
  • 90 ~ 95 is strong
  • 95 ~ 99 is very strong
  • 99 ~ 100 is invulnerable