add MD5 crypt

.github/workflows/md5-crypt.yml

@@ -0,0 +1,63 @@
+name: md5-crypt
+
+on:
+  pull_request:
+    paths:
+      - "md5-crypt/**"
+      - "Cargo.*"
+  push:
+    branches: master
+
+defaults:
+  run:
+    working-directory: md5-crypt
+
+env:
+  CARGO_INCREMENTAL: 0
+  RUSTFLAGS: "-Dwarnings"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - 1.56.0 # MSRV
+          - stable
+        target:
+          - thumbv7em-none-eabi
+          - wasm32-unknown-unknown
+    steps:
+      - uses: actions/checkout@v3
+      - uses: RustCrypto/actions/cargo-cache@master
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          target: ${{ matrix.target }}
+          override: true
+      - run: cargo build --target ${{ matrix.target }} --no-default-features
+
+  minimal-versions:
+    uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
+    with:
+        working-directory: ${{ github.workflow }}
+
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - 1.56.0 # MSRV
+          - stable
+    steps:
+      - uses: actions/checkout@v3
+      - uses: RustCrypto/actions/cargo-cache@master
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+      - run: cargo test --no-default-features
+      - run: cargo test
+      - run: cargo test --all-features

Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "argon2",
     "balloon-hash",
     "bcrypt-pbkdf",
+    "md5-crypt",
     "pbkdf2",
     "scrypt",
     "sha-crypt"

md5-crypt/CHANGELOG.md

@@ -0,0 +1,9 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## 0.1.0 (2022-10-17)
+- Initial release

md5-crypt/Cargo.toml

@@ -0,0 +1,33 @@
+[package]
+name = "md5-crypt"
+version = "0.1.0"
+description = """
+Pure Rust implementation of the MD5-crypt password hash as implemented by the
+POSIX crypt C library
+"""
+authors = ["RustCrypto Developers"]
+license = "MIT OR Apache-2.0"
+documentation = "https://docs.rs/md5-crypt"
+repository = "https://github.com/RustCrypto/password-hashes/tree/master/md5-crypt"
+categories = ["cryptography", "no-std"]
+keywords = ["crypto", "password", "hashing"]
+readme = "README.md"
+edition = "2021"
+rust-version = "1.56"
+
+[dependencies]
+
+# optional dependencies
+rand = { version = "0.8", optional = true }
+subtle = { version = ">=2, <2.5", optional = true, default-features = false }
+base64ct = "1.5.3"
+md-5 = { version = "0.10.5", default-features = false }
+
+[features]
+default = ["simple"]
+alloc = []
+simple = ["alloc", "rand", "subtle"]
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]

md5-crypt/LICENSE-APACHE

@@ -0,0 +1,201 @@
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md5-crypt/LICENSE-MIT

@@ -0,0 +1,25 @@
+Copyright (c) 2021 The RustCrypto Project Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

md5-crypt/README.md

@@ -0,0 +1,61 @@
+# RustCrypto: md5-crypt password hash
+
+[![crate][crate-image]][crate-link]
+[![Docs][docs-image]][docs-link]
+![Apache2/MIT licensed][license-image]
+![Rust Version][rustc-image]
+[![Project Chat][chat-image]][chat-link]
+[![Build Status][build-image]][build-link]
+
+Pure Rust implementation of the MD5-crypt password hash based on MD5,
+a legacy password hashing scheme supported by the [POSIX crypt C library][1].
+
+Password hashes using this algorithm start with `$1$` when encoded using the
+[PHC string format][2].
+
+[Documentation][docs-link]
+
+## Minimum Supported Rust Version
+
+Rust **1.56** or higher.
+
+Minimum supported Rust version can be changed in the future, but it will be
+done with a minor version bump.
+
+## SemVer Policy
+
+- All on-by-default features of this library are covered by SemVer
+- MSRV is considered exempt from SemVer as noted above
+
+## License
+
+Licensed under either of:
+
+ * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
+ * [MIT license](http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
+
+[//]: # (badges)
+
+[crate-image]: https://img.shields.io/crates/v/md5-crypt.svg
+[crate-link]: https://crates.io/crates/md5-crypt
+[docs-image]: https://docs.rs/md5-crypt/badge.svg
+[docs-link]: https://docs.rs/md5-crypt/
+[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.56+-blue.svg
+[chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
+[chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/260046-password-hashes
+[build-image]: https://github.com/RustCrypto/password-hashes/workflows/md5-crypt/badge.svg?branch=master&event=push
+[build-link]: https://github.com/RustCrypto/password-hashes/actions?query=workflow%3Amd5-crypt
+
+[//]: # (general links)
+
+[1]: https://en.wikipedia.org/wiki/Crypt_(C)
+[2]: https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md

md5-crypt/src/b64.rs

@@ -0,0 +1,44 @@
+//! Base64 encoding support
+
+use crate::defs::{BLOCK_SIZE, MAP_MD5, PW_SIZE_MD5};
+#[cfg(any(feature = "subtle", test))]
+use crate::errors::DecodeError;
+use base64ct::{Base64ShaCrypt, Encoding};
+
+pub fn encode_md5(source: &[u8]) -> [u8; PW_SIZE_MD5] {
+    let mut transposed = [0u8; BLOCK_SIZE];
+    for (i, &ti) in MAP_MD5.iter().enumerate() {
+        transposed[i] = source[ti as usize];
+    }
+    let mut buf = [0u8; PW_SIZE_MD5];
+    Base64ShaCrypt::encode(&transposed, &mut buf).unwrap();
+    buf
+}
+
+#[cfg(any(feature = "subtle", test))]
+pub fn decode_md5(source: &[u8]) -> Result<[u8; BLOCK_SIZE], DecodeError> {
+    let mut buf = [0u8; PW_SIZE_MD5];
+    Base64ShaCrypt::decode(source, &mut buf).map_err(|_| DecodeError)?;
+    let mut transposed = [0u8; BLOCK_SIZE];
+    for (i, &ti) in MAP_MD5.iter().enumerate() {
+        transposed[ti as usize] = buf[i];
+    }
+    Ok(transposed)
+}
+
+mod tests {
+    #[test]
+    fn test_encode_decode_md5() {
+        let original: [u8; 16] = [
+            0x0b, 0x5b, 0xdf, 0x7d, 0x92, 0xe2, 0xfc, 0xbd, 0xab, 0x57, 0xcb, 0xf3, 0xe0, 0x03,
+            0x16, 0x62,
+        ];
+
+        let e = super::encode_md5(&original);
+        let d = super::decode_md5(&e).unwrap();
+
+        for i in 0..d.len() {
+            assert_eq!(&original[i], &d[i]);
+        }
+    }
+}

md5-crypt/src/defs.rs

@@ -0,0 +1,15 @@
+/// Block size for MD5
+pub const BLOCK_SIZE: usize = 16;
+
+/// PWD part length of the password string
+pub const PW_SIZE_MD5: usize = 22;
+
+/// Maximum length of a salt
+pub const SALT_MAX_LEN: usize = 8;
+
+/// Encoding table.
+#[cfg(feature = "simple")]
+pub static TAB: &[u8] = b"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+/// Inverse encoding map for MD5.
+pub const MAP_MD5: [u8; BLOCK_SIZE] = [12, 6, 0, 13, 7, 1, 14, 8, 2, 15, 9, 3, 5, 10, 4, 11];

md5-crypt/src/errors.rs

@@ -0,0 +1,42 @@
+//! Error types.
+
+#[cfg(feature = "alloc")]
+use alloc::string;
+
+/// Error type.
+#[derive(Debug)]
+pub enum CryptError {
+    /// RNG failed.
+    RandomError,
+
+    /// UTF-8 error.
+    #[cfg(feature = "alloc")]
+    StringError(string::FromUtf8Error),
+}
+
+#[cfg(feature = "alloc")]
+impl From<string::FromUtf8Error> for CryptError {
+    fn from(e: string::FromUtf8Error) -> Self {
+        CryptError::StringError(e)
+    }
+}
+
+#[derive(Debug)]
+pub enum CheckError {
+    InvalidFormat(&'static str),
+    #[cfg(feature = "subtle")]
+    Crypt(CryptError),
+    #[cfg(feature = "subtle")]
+    HashMismatch,
+}
+
+/// Decoding errors.
+#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
+#[derive(Debug)]
+pub struct DecodeError;
+
+impl From<DecodeError> for CheckError {
+    fn from(_: DecodeError) -> CheckError {
+        CheckError::InvalidFormat("invalid B64")
+    }
+}

md5-crypt/src/lib.rs

@@ -0,0 +1,263 @@
+//! Pure Rust implementation of the `MD5-crypt` password hash based on md5,
+//! a legacy password hashing scheme supported by the [POSIX crypt C library][1].
+//!
+//! Password hashes using this algorithm start with `$1$` when encoded using the
+//! [PHC string format][2].
+//!
+//! # Usage
+//!
+//! ```
+//! # #[cfg(feature = "simple")]
+//! # {
+//! use md5_crypt::{md5_simple, md5_check};
+//!
+//! // Hash the password for storage
+//! let hashed_password = md5_simple("Not so secure password")
+//!     .expect("Should not fail");
+//!
+//! // Verifying a stored password
+//! assert!(md5_check("Not so secure password", &hashed_password).is_ok());
+//! # }
+//! ```
+//!
+//! [1]: https://en.wikipedia.org/wiki/Crypt_(C)
+//! [2]: https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md
+
+#![no_std]
+#![cfg_attr(docsrs, feature(doc_cfg))]
+#![doc(
+    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
+    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg"
+)]
+#![deny(unsafe_code)]
+#![warn(missing_docs, rust_2018_idioms)]
+
+// TODO(tarcieri): heapless support
+#[cfg(feature = "alloc")]
+extern crate alloc;
+
+mod b64;
+mod defs;
+mod errors;
+
+pub use crate::{
+    defs::{BLOCK_SIZE, PW_SIZE_MD5, SALT_MAX_LEN},
+    errors::CryptError,
+};
+
+use md5::{Digest, Md5};
+
+#[cfg(feature = "subtle")]
+use crate::errors::CheckError;
+
+#[cfg(feature = "simple")]
+use {
+    crate::defs::TAB,
+    alloc::string::String,
+    rand::{distributions::Distribution, thread_rng, Rng},
+};
+
+static MD5_SALT_PREFIX: &str = "$1$";
+
+/// The MD5 crypt function returned as byte vector
+///
+/// If the provided hash is longer than defs::SALT_MAX_LEN character, it will
+/// be stripped down to defs::SALT_MAX_LEN characters.
+///
+/// # Arguments
+/// - `password` - The password to process as a byte vector
+/// - `salt` - The salt value to use as a byte vector
+///   **WARNING: Make sure to compare this value in constant time!**
+///
+/// # Returns
+/// - `Ok(())` if calculation was successful
+/// - `Err(errors::CryptError)` otherwise
+pub fn md5_crypt(password: &[u8], salt: &[u8]) -> Result<[u8; BLOCK_SIZE], CryptError> {
+    let salt_len = salt.len();
+    let salt = match salt_len {
+        0..=SALT_MAX_LEN => &salt[0..salt_len],
+        _ => &salt[0..SALT_MAX_LEN],
+    };
+
+    let mut digest_b = Md5::default();
+    digest_b.update(password);
+    digest_b.update(salt);
+    digest_b.update(password);
+    let hash_b = digest_b.finalize();
+
+    let mut digest_a = Md5::default();
+    digest_a.update(password);
+    digest_a.update(MD5_SALT_PREFIX);
+    digest_a.update(salt);
+
+    let mut pw_len = password.len();
+    let rounds = pw_len / BLOCK_SIZE;
+    for _ in 0..rounds {
+        digest_a.update(hash_b);
+    }
+
+    // leftover password
+    digest_a.update(&hash_b[..(pw_len - rounds * BLOCK_SIZE)]);
+
+    while pw_len > 0 {
+        match pw_len & 1 {
+            0 => digest_a.update(&password[..1]),
+            1 => digest_a.update([0u8]),
+            _ => unreachable!(),
+        }
+        pw_len >>= 1;
+    }
+
+    let mut hash_a = digest_a.finalize();
+
+    // Repeatedly run the collected hash value through MD5 to burn
+    // CPU cycles
+    for i in 0..1000_usize {
+        // new hasher
+        let mut hasher = Md5::default();
+
+        // Add key or last result
+        if (i & 1) != 0 {
+            hasher.update(password);
+        } else {
+            hasher.update(hash_a);
+        }
+
+        // Add salt for numbers not divisible by 3
+        if i % 3 != 0 {
+            hasher.update(salt);
+        }
+
+        // Add key for numbers not divisible by 7
+        if i % 7 != 0 {
+            hasher.update(password);
+        }
+
+        // Add key or last result
+        if (i & 1) != 0 {
+            hasher.update(hash_a);
+        } else {
+            hasher.update(password);
+        }
+
+        // digest_c.clone_from_slice(&hasher.finalize());
+        hash_a = hasher.finalize();
+    }
+
+    Ok(hash_a.into())
+}
+
+/// Same as md5_crypt except base64 representation will be returned.
+///
+/// # Arguments
+/// - `password` - The password to process as a byte vector
+/// - `salt` - The salt value to use as a byte vector
+///   **WARNING: Make sure to compare this value in constant time!**
+///
+/// # Returns
+/// - `Ok(())` if calculation was successful
+/// - `Err(errors::CryptError)` otherwise
+pub fn md5_crypt_b64(password: &[u8], salt: &[u8]) -> Result<[u8; PW_SIZE_MD5], CryptError> {
+    let output = md5_crypt(password, salt)?;
+    Ok(b64::encode_md5(&output))
+}
+
+/// Simple interface for generating a MD5 password hash.
+///
+/// The salt will be chosen randomly.
+///
+///  `$<ID>$<SALT>$<HASH>`
+///
+/// # Returns
+/// - `Ok(String)` containing the full MD5 password hash format on success
+/// - `Err(CryptError)` if something went wrong.
+#[cfg(feature = "simple")]
+#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
+pub fn md5_simple(password: &str) -> Result<String, CryptError> {
+    let rng = thread_rng();
+
+    let salt: String = rng
+        .sample_iter(&Md5CryptDistribution)
+        .take(SALT_MAX_LEN)
+        .collect();
+
+    let out = md5_crypt(password.as_bytes(), salt.as_bytes())?;
+
+    let mut result = String::new();
+    result.push_str(MD5_SALT_PREFIX);
+    result.push_str(&salt);
+    result.push('$');
+    let s = String::from_utf8(b64::encode_md5(&out).to_vec())?;
+    result.push_str(&s);
+    Ok(result)
+}
+
+/// Checks that given password matches provided hash.
+///
+/// # Arguments
+/// - `password` - expected password
+/// - `hashed_value` - the hashed value which should be used for checking,
+/// should be of format mentioned `$1$<SALT>$<PWD>`.
+///
+/// # Return
+/// `OK(())` if password matches otherwise Err(CheckError) in case of invalid
+/// format or password mismatch.
+#[cfg(feature = "subtle")]
+#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
+pub fn md5_check(password: &str, hashed_value: &str) -> Result<(), CheckError> {
+    let mut iter = hashed_value.split('$');
+
+    // Check that there are no characters before the first "$"
+    if iter.next() != Some("") {
+        return Err(CheckError::InvalidFormat("Should start with '$"));
+    }
+
+    if iter.next() != Some("1") {
+        return Err(CheckError::InvalidFormat(
+            "does not contain MD5 identifier: '$1$'",
+        ));
+    }
+
+    let next = iter.next().ok_or(CheckError::InvalidFormat(
+        "Does not contain a salt or hash string",
+    ))?;
+
+    let salt = next;
+
+    let hash = iter
+        .next()
+        .ok_or(CheckError::InvalidFormat("Does not contain a hash string"))?;
+
+    // Make sure there is no trailing data after the final "$"
+    if iter.next().is_some() {
+        return Err(CheckError::InvalidFormat("Trailing characters present"));
+    }
+
+    let output = md5_crypt(password.as_bytes(), salt.as_bytes()).map_err(CheckError::Crypt)?;
+
+    let hash = b64::decode_md5(hash.as_bytes())?;
+
+    use subtle::ConstantTimeEq;
+    if output.ct_eq(&hash).into() {
+        Ok(())
+    } else {
+        Err(CheckError::HashMismatch)
+    }
+}
+
+#[cfg(feature = "simple")]
+#[derive(Debug)]
+struct Md5CryptDistribution;
+
+#[cfg(feature = "simple")]
+impl Distribution<char> for Md5CryptDistribution {
+    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> char {
+        const RANGE: u32 = 26 + 26 + 10 + 2; // 2 == "./"
+        loop {
+            let var = rng.next_u32() >> (32 - 6);
+            if var < RANGE {
+                return TAB[var as usize] as char;
+            }
+        }
+    }
+}

md5-crypt/tests/lib.rs

@@ -0,0 +1,132 @@
+use md5_crypt::md5_crypt_b64;
+
+#[cfg(feature = "simple")]
+use md5_crypt::{md5_check, md5_simple};
+
+use std::str;
+
+struct TestVector {
+    input: &'static str,
+    salt: &'static str,
+    result: &'static str,
+}
+
+const TEST_VECTORS: &[TestVector] = &[
+    TestVector {
+        input: "",
+        salt: "salt",
+        result: "UsdFqFVB.FsuinRDK5eE..",
+    },
+    TestVector {
+        input: "abc",
+        salt: "salt",
+        result: "Ix0K7gMcCieLMZGthf6yT1",
+    },
+    TestVector {
+        input: "Hello world!",
+        salt: "salt",
+        result: "wa8aFuC3rkp5bjoBIGTc41",
+    },
+    TestVector {
+        input: "Hello world!",
+        salt: "saltsalt",
+        result: "le8lFSqqnPaRFOlmAZpvH1",
+    },
+    TestVector {
+        input: "This is just a test",
+        salt: "saltsalt",
+        result: "GG3.Tf92SRQMW0mClBXo..",
+    },
+    // 63 length password
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+        salt: "kf8.jB3Z",
+        result: "UZFByQYndkZGAc9kqF4A21",
+    },
+    // 64 length password
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", // 64 length
+        salt: "kf8.jB3Z",
+        result: ".XRGr/PlZPFr11frOZsYQ0",
+    },
+    // 65 length password
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", // 65 length
+        salt: "kf8.jB3Z",
+        result: "xErCjUcXBWx7JNSY/bdJM1",
+    },
+    // 127 length password
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+        salt: "kf8.jB3Z",
+        result: "ay9BDuVT.pV2B.EX6V4HC1",
+    },
+    // 128 length password
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+        salt: "kf8.jB3Z",
+        result: "kZ6Ws32gDHOGf1DEqpBUq.",
+    },
+    // 129 length password 
+    TestVector {
+        input: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+        salt: "kf8.jB3Z",
+        result: "5hc1Ea4UM8OzOhdb2/WvW0",
+    },
+];
+
+#[test]
+fn test_md5_crypt() {
+    for t in TEST_VECTORS {
+        let result_array = md5_crypt_b64(t.input.as_bytes(), t.salt.as_bytes()).unwrap();
+        let result = str::from_utf8(&result_array).unwrap();
+        assert!(result == t.result);
+    }
+}
+
+#[cfg(feature = "simple")]
+#[test]
+fn test_md5_check() {
+    let pw = "foobar";
+    let s = "$1$NoaSCTUg$j91ZS4vEeaHDdpecPbzkY0";
+    assert!(md5_check(pw, s).is_ok());
+}
+
+#[cfg(feature = "simple")]
+#[test]
+fn test_md5_simple_check_roundtrip() {
+    let pw = "this is my password";
+
+    let r = md5_simple(&pw);
+    assert!(r.is_ok());
+    let hash = r.unwrap();
+
+    let c_r = md5_check(&pw, &hash);
+    assert!(c_r.is_ok());
+}
+
+#[cfg(feature = "simple")]
+#[test]
+fn test_md5_unexpected_prefix() {
+    let pw = "foobar";
+    let s = "SHOULDNOTBEHERE$1$WtWGiGnH$Ryci5v8qFuzlfj25Yye97";
+    assert!(!md5_check(pw, s).is_ok());
+}
+
+#[cfg(feature = "simple")]
+#[test]
+fn test_md5_wrong_id() {
+    // wrong id '2'
+    let pw = "foobar";
+    let s = "$2$WtWGiGnH$Ryci5v8qFuzlfj25Yye97";
+    assert!(!md5_check(pw, s).is_ok());
+}
+
+#[cfg(feature = "simple")]
+#[test]
+fn test_md5_missing_trailing_slash() {
+    // Missing trailing slash
+    let pw = "abc";
+    let s = "$1$/dUAwECj$E7lsyZl3NQqTePIPi4/42";
+    assert!(!md5_check(pw, s).is_ok());
+}