noxtls-crypto 0.1.3

// Copyright (c) 2019-2026, Argenox Technologies LLC
// All rights reserved.
//
// SPDX-License-Identifier: GPL-2.0-only OR LicenseRef-Argenox-Commercial-License
//
// This file is part of the NoxTLS Library.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by the
// Free Software Foundation; version 2 of the License.
//
// Alternatively, this file may be used under the terms of a commercial
// license from Argenox Technologies LLC.
//
// See `noxtls/LICENSE` and `noxtls/LICENSE.md` in this repository for full details.
// CONTACT: info@argenox.com

//! OpenBSD-compatible bcrypt_pbkdf using SHA-512 preprocessing and EksBlowfish.

use crate::internal_alloc::Vec;
use noxtls_core::{Error, Result};

const BCRYPT_WORDS: usize = 8;
const BCRYPT_HASHSIZE: usize = BCRYPT_WORDS * 4;
const BCRYPT_MAX_KEY_LEN: usize = BCRYPT_HASHSIZE * BCRYPT_HASHSIZE;
const BCRYPT_SETUP_ROUNDS: usize = 64;
const BCRYPT_ENCRYPT_ROUNDS: usize = 64;
const BCRYPT_MAGIC: &[u8; BCRYPT_HASHSIZE] = b"OxychromaticBlowfishSwatDynamite";

/// Holds Blowfish P-array and S-box state for EksBlowfish operations.
#[derive(Clone)]
struct BlowfishState {
    p: [u32; 18],
    s: [[u32; 256]; 4],
}

impl BlowfishState {
    /// Creates a Blowfish state initialized to the standard digits-of-pi constants.
    ///
    /// # Arguments
    ///
    /// No arguments.
    ///
    /// # Returns
    ///
    /// Fresh [`BlowfishState`] ready for key expansion.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn new() -> Self {
        Self {
            p: BLOWFISH_P_INIT,
            s: BLOWFISH_S_INIT,
        }
    }

    /// Computes the Blowfish F function for one 32-bit input word.
    ///
    /// # Arguments
    ///
    /// * `self` - Blowfish state providing S-box tables.
    /// * `x` - 32-bit input word to transform.
    ///
    /// # Returns
    ///
    /// One 32-bit F-function output.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn feistel(&self, x: u32) -> u32 {
        let a = (x >> 24) as usize;
        let b = ((x >> 16) & 0xff) as usize;
        let c = ((x >> 8) & 0xff) as usize;
        let d = (x & 0xff) as usize;

        (self.s[0][a].wrapping_add(self.s[1][b]) ^ self.s[2][c]).wrapping_add(self.s[3][d])
    }

    /// Enciphers one Blowfish 64-bit block represented as two 32-bit words.
    ///
    /// # Arguments
    ///
    /// * `self` - Blowfish key schedule and S-box state.
    /// * `xl` - Left 32-bit word of the input block.
    /// * `xr` - Right 32-bit word of the input block.
    ///
    /// # Returns
    ///
    /// Tuple `(left, right)` containing the encrypted block words.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn encipher(&self, xl: u32, xr: u32) -> (u32, u32) {
        let mut left = xl ^ self.p[0];
        let mut right = xr;
        let mut round = 1_usize;

        while round <= 16 {
            right ^= self.feistel(left) ^ self.p[round];
            round += 1;
            left ^= self.feistel(right) ^ self.p[round];
            round += 1;
        }

        let out_left = right ^ self.p[17];
        let out_right = left;
        (out_left, out_right)
    }

    /// Extracts a wrapped 32-bit big-endian word from a byte stream.
    ///
    /// # Arguments
    ///
    /// * `data` - Non-empty byte stream used as a circular source.
    /// * `current` - Current read index, updated to the next stream position.
    ///
    /// # Returns
    ///
    /// One 32-bit word assembled from four sequential bytes.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn stream_to_word(data: &[u8], current: &mut usize) -> u32 {
        let mut word = 0_u32;
        let mut index = *current;

        for _ in 0..4 {
            if index >= data.len() {
                index = 0;
            }
            word = (word << 8) | u32::from(data[index]);
            index += 1;
        }

        *current = index;
        word
    }

    /// Performs Blowfish key expansion using key material only (`ExpandKey` with zero data).
    ///
    /// # Arguments
    ///
    /// * `self` - Blowfish state to mutate in place.
    /// * `key` - Non-empty key stream bytes.
    ///
    /// # Returns
    ///
    /// `()`; updates `P` and `S` tables.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn expand0state(&mut self, key: &[u8]) {
        let mut key_index = 0_usize;
        for p_word in &mut self.p {
            *p_word ^= Self::stream_to_word(key, &mut key_index);
        }

        let mut datal = 0_u32;
        let mut datar = 0_u32;
        for index in (0..self.p.len()).step_by(2) {
            (datal, datar) = self.encipher(datal, datar);
            self.p[index] = datal;
            self.p[index + 1] = datar;
        }

        for box_index in 0..4 {
            for slot in (0..256).step_by(2) {
                (datal, datar) = self.encipher(datal, datar);
                self.s[box_index][slot] = datal;
                self.s[box_index][slot + 1] = datar;
            }
        }
    }

    /// Performs EksBlowfish expansion using both data and key streams.
    ///
    /// # Arguments
    ///
    /// * `self` - Blowfish state to mutate in place.
    /// * `data` - Non-empty data stream mixed into expansion state.
    /// * `key` - Non-empty key stream bytes.
    ///
    /// # Returns
    ///
    /// `()`; updates `P` and `S` tables.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn expand_state(&mut self, data: &[u8], key: &[u8]) {
        let mut key_index = 0_usize;
        for p_word in &mut self.p {
            *p_word ^= Self::stream_to_word(key, &mut key_index);
        }

        let mut data_index = 0_usize;
        let mut datal = 0_u32;
        let mut datar = 0_u32;

        for index in (0..self.p.len()).step_by(2) {
            datal ^= Self::stream_to_word(data, &mut data_index);
            datar ^= Self::stream_to_word(data, &mut data_index);
            (datal, datar) = self.encipher(datal, datar);
            self.p[index] = datal;
            self.p[index + 1] = datar;
        }

        for box_index in 0..4 {
            for slot in (0..256).step_by(2) {
                datal ^= Self::stream_to_word(data, &mut data_index);
                datar ^= Self::stream_to_word(data, &mut data_index);
                (datal, datar) = self.encipher(datal, datar);
                self.s[box_index][slot] = datal;
                self.s[box_index][slot + 1] = datar;
            }
        }
    }

    /// Encrypts a mutable u32 slice as sequential Blowfish blocks.
    ///
    /// # Arguments
    ///
    /// * `self` - Blowfish state used for block encryption.
    /// * `words` - Even-length list of words, two words per 64-bit block.
    ///
    /// # Returns
    ///
    /// `()`; writes encrypted words back into `words`.
    ///
    /// # Panics
    ///
    /// This function does not panic.
    fn encrypt_words(&self, words: &mut [u32]) {
        for block in words.chunks_exact_mut(2) {
            let (left, right) = self.encipher(block[0], block[1]);
            block[0] = left;
            block[1] = right;
        }
    }
}

/// Computes one OpenBSD bcrypt hash block from SHA-512 preprocessed password and salt.
///
/// # Arguments
///
/// * `sha2_pass` - 64-byte SHA-512 digest of the original password.
/// * `sha2_salt` - 64-byte SHA-512 digest of the salt (or per-round chaining value).
///
/// # Returns
///
/// 32-byte bcrypt hash block in OpenBSD output byte ordering.
///
/// # Panics
///
/// This function does not panic.
#[must_use]
fn bcrypt_hash(sha2_pass: &[u8; 64], sha2_salt: &[u8; 64]) -> [u8; BCRYPT_HASHSIZE] {
    let mut state = BlowfishState::new();
    state.expand_state(sha2_salt, sha2_pass);
    for _ in 0..BCRYPT_SETUP_ROUNDS {
        state.expand0state(sha2_salt);
        state.expand0state(sha2_pass);
    }

    let mut cdata = [0_u32; BCRYPT_WORDS];
    let mut cursor = 0_usize;
    for word in &mut cdata {
        *word = BlowfishState::stream_to_word(BCRYPT_MAGIC, &mut cursor);
    }

    for _ in 0..BCRYPT_ENCRYPT_ROUNDS {
        state.encrypt_words(&mut cdata);
    }

    let mut out = [0_u8; BCRYPT_HASHSIZE];
    for (index, word) in cdata.iter().enumerate() {
        out[4 * index + 3] = (word >> 24) as u8;
        out[4 * index + 2] = (word >> 16) as u8;
        out[4 * index + 1] = (word >> 8) as u8;
        out[4 * index] = *word as u8;
    }
    out
}

/// Derives key bytes with OpenBSD-compatible bcrypt_pbkdf using SHA-512 preprocessing.
///
/// # Arguments
///
/// * `password` - Password bytes to preprocess with SHA-512 (must not be empty).
/// * `salt` - Salt bytes to preprocess with SHA-512 and 32-bit block counters (must not be empty).
/// * `rounds` - Number of bcrypt_pbkdf iterations; must be greater than zero.
/// * `key_len` - Number of output key bytes to derive; must be greater than zero.
///
/// # Returns
///
/// On success, a [`Vec`] containing exactly `key_len` bytes mixed in OpenBSD's nonlinear layout.
///
/// # Errors
///
/// Returns [`Error::InvalidLength`] when `rounds == 0`, `key_len == 0`, `password` is empty,
/// `salt` is empty, or `key_len` exceeds OpenBSD's bcrypt_pbkdf upper bound (`1024` bytes).
///
/// # Panics
///
/// This function does not panic.
pub fn bcrypt_pbkdf_sha512(
    password: &[u8],
    salt: &[u8],
    rounds: u32,
    key_len: usize,
) -> Result<Vec<u8>> {
    if rounds == 0 {
        return Err(Error::InvalidLength("bcrypt_pbkdf rounds must be non-zero"));
    }
    if key_len == 0 {
        return Err(Error::InvalidLength(
            "bcrypt_pbkdf key_len must be non-zero",
        ));
    }
    if password.is_empty() {
        return Err(Error::InvalidLength(
            "bcrypt_pbkdf password must not be empty",
        ));
    }
    if salt.is_empty() {
        return Err(Error::InvalidLength("bcrypt_pbkdf salt must not be empty"));
    }
    if key_len > BCRYPT_MAX_KEY_LEN {
        return Err(Error::InvalidLength(
            "bcrypt_pbkdf key_len exceeds OpenBSD limit",
        ));
    }

    let mut key = vec![0_u8; key_len];
    let sha2_pass = super::sha512(password);

    let stride = key_len.div_ceil(BCRYPT_HASHSIZE);
    let mut amount = key_len.div_ceil(stride);
    let mut remaining = key_len;
    let mut counter = 1_u32;

    while remaining > 0 {
        let mut salt_block = Vec::with_capacity(salt.len() + 4);
        salt_block.extend_from_slice(salt);
        salt_block.extend_from_slice(&counter.to_be_bytes());

        let mut sha2_salt = super::sha512(&salt_block);
        let mut tmp = bcrypt_hash(&sha2_pass, &sha2_salt);
        let mut out = tmp;

        for _ in 1..rounds {
            sha2_salt = super::sha512(&tmp);
            tmp = bcrypt_hash(&sha2_pass, &sha2_salt);
            for (left, right) in out.iter_mut().zip(tmp.iter()) {
                *left ^= *right;
            }
        }

        amount = amount.min(remaining);
        let mut copied = 0_usize;
        for (i, byte) in out.iter().copied().take(amount).enumerate() {
            let dest = i * stride + (counter as usize - 1);
            if dest >= key_len {
                break;
            }
            key[dest] = byte;
            copied += 1;
        }

        remaining -= copied;
        counter = counter.wrapping_add(1);
    }

    Ok(key)
}

const BLOWFISH_P_INIT: [u32; 18] = [
    0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344, 0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
    0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c, 0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917,
    0x9216d5d9, 0x8979fb1b,
];

#[rustfmt::skip]
const BLOWFISH_S_INIT: [[u32; 256]; 4] = [
    [
        0xd1310ba6, 0x98dfb5ac, 0x2ffd72db, 0xd01adfb7, 0xb8e1afed, 0x6a267e96, 0xba7c9045, 0xf12c7f99,
        0x24a19947, 0xb3916cf7, 0x0801f2e2, 0x858efc16, 0x636920d8, 0x71574e69, 0xa458fea3, 0xf4933d7e,
        0x0d95748f, 0x728eb658, 0x718bcd58, 0x82154aee, 0x7b54a41d, 0xc25a59b5, 0x9c30d539, 0x2af26013,
        0xc5d1b023, 0x286085f0, 0xca417918, 0xb8db38ef, 0x8e79dcb0, 0x603a180e, 0x6c9e0e8b, 0xb01e8a3e,
        0xd71577c1, 0xbd314b27, 0x78af2fda, 0x55605c60, 0xe65525f3, 0xaa55ab94, 0x57489862, 0x63e81440,
        0x55ca396a, 0x2aab10b6, 0xb4cc5c34, 0x1141e8ce, 0xa15486af, 0x7c72e993, 0xb3ee1411, 0x636fbc2a,
        0x2ba9c55d, 0x741831f6, 0xce5c3e16, 0x9b87931e, 0xafd6ba33, 0x6c24cf5c, 0x7a325381, 0x28958677,
        0x3b8f4898, 0x6b4bb9af, 0xc4bfe81b, 0x66282193, 0x61d809cc, 0xfb21a991, 0x487cac60, 0x5dec8032,
        0xef845d5d, 0xe98575b1, 0xdc262302, 0xeb651b88, 0x23893e81, 0xd396acc5, 0x0f6d6ff3, 0x83f44239,
        0x2e0b4482, 0xa4842004, 0x69c8f04a, 0x9e1f9b5e, 0x21c66842, 0xf6e96c9a, 0x670c9c61, 0xabd388f0,
        0x6a51a0d2, 0xd8542f68, 0x960fa728, 0xab5133a3, 0x6eef0b6c, 0x137a3be4, 0xba3bf050, 0x7efb2a98,
        0xa1f1651d, 0x39af0176, 0x66ca593e, 0x82430e88, 0x8cee8619, 0x456f9fb4, 0x7d84a5c3, 0x3b8b5ebe,
        0xe06f75d8, 0x85c12073, 0x401a449f, 0x56c16aa6, 0x4ed3aa62, 0x363f7706, 0x1bfedf72, 0x429b023d,
        0x37d0d724, 0xd00a1248, 0xdb0fead3, 0x49f1c09b, 0x075372c9, 0x80991b7b, 0x25d479d8, 0xf6e8def7,
        0xe3fe501a, 0xb6794c3b, 0x976ce0bd, 0x04c006ba, 0xc1a94fb6, 0x409f60c4, 0x5e5c9ec2, 0x196a2463,
        0x68fb6faf, 0x3e6c53b5, 0x1339b2eb, 0x3b52ec6f, 0x6dfc511f, 0x9b30952c, 0xcc814544, 0xaf5ebd09,
        0xbee3d004, 0xde334afd, 0x660f2807, 0x192e4bb3, 0xc0cba857, 0x45c8740f, 0xd20b5f39, 0xb9d3fbdb,
        0x5579c0bd, 0x1a60320a, 0xd6a100c6, 0x402c7279, 0x679f25fe, 0xfb1fa3cc, 0x8ea5e9f8, 0xdb3222f8,
        0x3c7516df, 0xfd616b15, 0x2f501ec8, 0xad0552ab, 0x323db5fa, 0xfd238760, 0x53317b48, 0x3e00df82,
        0x9e5c57bb, 0xca6f8ca0, 0x1a87562e, 0xdf1769db, 0xd542a8f6, 0x287effc3, 0xac6732c6, 0x8c4f5573,
        0x695b27b0, 0xbbca58c8, 0xe1ffa35d, 0xb8f011a0, 0x10fa3d98, 0xfd2183b8, 0x4afcb56c, 0x2dd1d35b,
        0x9a53e479, 0xb6f84565, 0xd28e49bc, 0x4bfb9790, 0xe1ddf2da, 0xa4cb7e33, 0x62fb1341, 0xcee4c6e8,
        0xef20cada, 0x36774c01, 0xd07e9efe, 0x2bf11fb4, 0x95dbda4d, 0xae909198, 0xeaad8e71, 0x6b93d5a0,
        0xd08ed1d0, 0xafc725e0, 0x8e3c5b2f, 0x8e7594b7, 0x8ff6e2fb, 0xf2122b64, 0x8888b812, 0x900df01c,
        0x4fad5ea0, 0x688fc31c, 0xd1cff191, 0xb3a8c1ad, 0x2f2f2218, 0xbe0e1777, 0xea752dfe, 0x8b021fa1,
        0xe5a0cc0f, 0xb56f74e8, 0x18acf3d6, 0xce89e299, 0xb4a84fe0, 0xfd13e0b7, 0x7cc43b81, 0xd2ada8d9,
        0x165fa266, 0x80957705, 0x93cc7314, 0x211a1477, 0xe6ad2065, 0x77b5fa86, 0xc75442f5, 0xfb9d35cf,
        0xebcdaf0c, 0x7b3e89a0, 0xd6411bd3, 0xae1e7e49, 0x00250e2d, 0x2071b35e, 0x226800bb, 0x57b8e0af,
        0x2464369b, 0xf009b91e, 0x5563911d, 0x59dfa6aa, 0x78c14389, 0xd95a537f, 0x207d5ba2, 0x02e5b9c5,
        0x83260376, 0x6295cfa9, 0x11c81968, 0x4e734a41, 0xb3472dca, 0x7b14a94a, 0x1b510052, 0x9a532915,
        0xd60f573f, 0xbc9bc6e4, 0x2b60a476, 0x81e67400, 0x08ba6fb5, 0x571be91f, 0xf296ec6b, 0x2a0dd915,
        0xb6636521, 0xe7b9f9b6, 0xff34052e, 0xc5855664, 0x53b02d5d, 0xa99f8fa1, 0x08ba4799, 0x6e85076a,
    ],
    [
        0x4b7a70e9, 0xb5b32944, 0xdb75092e, 0xc4192623, 0xad6ea6b0, 0x49a7df7d, 0x9cee60b8, 0x8fedb266,
        0xecaa8c71, 0x699a17ff, 0x5664526c, 0xc2b19ee1, 0x193602a5, 0x75094c29, 0xa0591340, 0xe4183a3e,
        0x3f54989a, 0x5b429d65, 0x6b8fe4d6, 0x99f73fd6, 0xa1d29c07, 0xefe830f5, 0x4d2d38e6, 0xf0255dc1,
        0x4cdd2086, 0x8470eb26, 0x6382e9c6, 0x021ecc5e, 0x09686b3f, 0x3ebaefc9, 0x3c971814, 0x6b6a70a1,
        0x687f3584, 0x52a0e286, 0xb79c5305, 0xaa500737, 0x3e07841c, 0x7fdeae5c, 0x8e7d44ec, 0x5716f2b8,
        0xb03ada37, 0xf0500c0d, 0xf01c1f04, 0x0200b3ff, 0xae0cf51a, 0x3cb574b2, 0x25837a58, 0xdc0921bd,
        0xd19113f9, 0x7ca92ff6, 0x94324773, 0x22f54701, 0x3ae5e581, 0x37c2dadc, 0xc8b57634, 0x9af3dda7,
        0xa9446146, 0x0fd0030e, 0xecc8c73e, 0xa4751e41, 0xe238cd99, 0x3bea0e2f, 0x3280bba1, 0x183eb331,
        0x4e548b38, 0x4f6db908, 0x6f420d03, 0xf60a04bf, 0x2cb81290, 0x24977c79, 0x5679b072, 0xbcaf89af,
        0xde9a771f, 0xd9930810, 0xb38bae12, 0xdccf3f2e, 0x5512721f, 0x2e6b7124, 0x501adde6, 0x9f84cd87,
        0x7a584718, 0x7408da17, 0xbc9f9abc, 0xe94b7d8c, 0xec7aec3a, 0xdb851dfa, 0x63094366, 0xc464c3d2,
        0xef1c1847, 0x3215d908, 0xdd433b37, 0x24c2ba16, 0x12a14d43, 0x2a65c451, 0x50940002, 0x133ae4dd,
        0x71dff89e, 0x10314e55, 0x81ac77d6, 0x5f11199b, 0x043556f1, 0xd7a3c76b, 0x3c11183b, 0x5924a509,
        0xf28fe6ed, 0x97f1fbfa, 0x9ebabf2c, 0x1e153c6e, 0x86e34570, 0xeae96fb1, 0x860e5e0a, 0x5a3e2ab3,
        0x771fe71c, 0x4e3d06fa, 0x2965dcb9, 0x99e71d0f, 0x803e89d6, 0x5266c825, 0x2e4cc978, 0x9c10b36a,
        0xc6150eba, 0x94e2ea78, 0xa5fc3c53, 0x1e0a2df4, 0xf2f74ea7, 0x361d2b3d, 0x1939260f, 0x19c27960,
        0x5223a708, 0xf71312b6, 0xebadfe6e, 0xeac31f66, 0xe3bc4595, 0xa67bc883, 0xb17f37d1, 0x018cff28,
        0xc332ddef, 0xbe6c5aa5, 0x65582185, 0x68ab9802, 0xeecea50f, 0xdb2f953b, 0x2aef7dad, 0x5b6e2f84,
        0x1521b628, 0x29076170, 0xecdd4775, 0x619f1510, 0x13cca830, 0xeb61bd96, 0x0334fe1e, 0xaa0363cf,
        0xb5735c90, 0x4c70a239, 0xd59e9e0b, 0xcbaade14, 0xeecc86bc, 0x60622ca7, 0x9cab5cab, 0xb2f3846e,
        0x648b1eaf, 0x19bdf0ca, 0xa02369b9, 0x655abb50, 0x40685a32, 0x3c2ab4b3, 0x319ee9d5, 0xc021b8f7,
        0x9b540b19, 0x875fa099, 0x95f7997e, 0x623d7da8, 0xf837889a, 0x97e32d77, 0x11ed935f, 0x16681281,
        0x0e358829, 0xc7e61fd6, 0x96dedfa1, 0x7858ba99, 0x57f584a5, 0x1b227263, 0x9b83c3ff, 0x1ac24696,
        0xcdb30aeb, 0x532e3054, 0x8fd948e4, 0x6dbc3128, 0x58ebf2ef, 0x34c6ffea, 0xfe28ed61, 0xee7c3c73,
        0x5d4a14d9, 0xe864b7e3, 0x42105d14, 0x203e13e0, 0x45eee2b6, 0xa3aaabea, 0xdb6c4f15, 0xfacb4fd0,
        0xc742f442, 0xef6abbb5, 0x654f3b1d, 0x41cd2105, 0xd81e799e, 0x86854dc7, 0xe44b476a, 0x3d816250,
        0xcf62a1f2, 0x5b8d2646, 0xfc8883a0, 0xc1c7b6a3, 0x7f1524c3, 0x69cb7492, 0x47848a0b, 0x5692b285,
        0x095bbf00, 0xad19489d, 0x1462b174, 0x23820e00, 0x58428d2a, 0x0c55f5ea, 0x1dadf43e, 0x233f7061,
        0x3372f092, 0x8d937e41, 0xd65fecf1, 0x6c223bdb, 0x7cde3759, 0xcbee7460, 0x4085f2a7, 0xce77326e,
        0xa6078084, 0x19f8509e, 0xe8efd855, 0x61d99735, 0xa969a7aa, 0xc50c06c2, 0x5a04abfc, 0x800bcadc,
        0x9e447a2e, 0xc3453484, 0xfdd56705, 0x0e1e9ec9, 0xdb73dbd3, 0x105588cd, 0x675fda79, 0xe3674340,
        0xc5c43465, 0x713e38d8, 0x3d28f89e, 0xf16dff20, 0x153e21e7, 0x8fb03d4a, 0xe6e39f2b, 0xdb83adf7,
    ],
    [
        0xe93d5a68, 0x948140f7, 0xf64c261c, 0x94692934, 0x411520f7, 0x7602d4f7, 0xbcf46b2e, 0xd4a20068,
        0xd4082471, 0x3320f46a, 0x43b7d4b7, 0x500061af, 0x1e39f62e, 0x97244546, 0x14214f74, 0xbf8b8840,
        0x4d95fc1d, 0x96b591af, 0x70f4ddd3, 0x66a02f45, 0xbfbc09ec, 0x03bd9785, 0x7fac6dd0, 0x31cb8504,
        0x96eb27b3, 0x55fd3941, 0xda2547e6, 0xabca0a9a, 0x28507825, 0x530429f4, 0x0a2c86da, 0xe9b66dfb,
        0x68dc1462, 0xd7486900, 0x680ec0a4, 0x27a18dee, 0x4f3ffea2, 0xe887ad8c, 0xb58ce006, 0x7af4d6b6,
        0xaace1e7c, 0xd3375fec, 0xce78a399, 0x406b2a42, 0x20fe9e35, 0xd9f385b9, 0xee39d7ab, 0x3b124e8b,
        0x1dc9faf7, 0x4b6d1856, 0x26a36631, 0xeae397b2, 0x3a6efa74, 0xdd5b4332, 0x6841e7f7, 0xca7820fb,
        0xfb0af54e, 0xd8feb397, 0x454056ac, 0xba489527, 0x55533a3a, 0x20838d87, 0xfe6ba9b7, 0xd096954b,
        0x55a867bc, 0xa1159a58, 0xcca92963, 0x99e1db33, 0xa62a4a56, 0x3f3125f9, 0x5ef47e1c, 0x9029317c,
        0xfdf8e802, 0x04272f70, 0x80bb155c, 0x05282ce3, 0x95c11548, 0xe4c66d22, 0x48c1133f, 0xc70f86dc,
        0x07f9c9ee, 0x41041f0f, 0x404779a4, 0x5d886e17, 0x325f51eb, 0xd59bc0d1, 0xf2bcc18f, 0x41113564,
        0x257b7834, 0x602a9c60, 0xdff8e8a3, 0x1f636c1b, 0x0e12b4c2, 0x02e1329e, 0xaf664fd1, 0xcad18115,
        0x6b2395e0, 0x333e92e1, 0x3b240b62, 0xeebeb922, 0x85b2a20e, 0xe6ba0d99, 0xde720c8c, 0x2da2f728,
        0xd0127845, 0x95b794fd, 0x647d0862, 0xe7ccf5f0, 0x5449a36f, 0x877d48fa, 0xc39dfd27, 0xf33e8d1e,
        0x0a476341, 0x992eff74, 0x3a6f6eab, 0xf4f8fd37, 0xa812dc60, 0xa1ebddf8, 0x991be14c, 0xdb6e6b0d,
        0xc67b5510, 0x6d672c37, 0x2765d43b, 0xdcd0e804, 0xf1290dc7, 0xcc00ffa3, 0xb5390f92, 0x690fed0b,
        0x667b9ffb, 0xcedb7d9c, 0xa091cf0b, 0xd9155ea3, 0xbb132f88, 0x515bad24, 0x7b9479bf, 0x763bd6eb,
        0x37392eb3, 0xcc115979, 0x8026e297, 0xf42e312d, 0x6842ada7, 0xc66a2b3b, 0x12754ccc, 0x782ef11c,
        0x6a124237, 0xb79251e7, 0x06a1bbe6, 0x4bfb6350, 0x1a6b1018, 0x11caedfa, 0x3d25bdd8, 0xe2e1c3c9,
        0x44421659, 0x0a121386, 0xd90cec6e, 0xd5abea2a, 0x64af674e, 0xda86a85f, 0xbebfe988, 0x64e4c3fe,
        0x9dbc8057, 0xf0f7c086, 0x60787bf8, 0x6003604d, 0xd1fd8346, 0xf6381fb0, 0x7745ae04, 0xd736fccc,
        0x83426b33, 0xf01eab71, 0xb0804187, 0x3c005e5f, 0x77a057be, 0xbde8ae24, 0x55464299, 0xbf582e61,
        0x4e58f48f, 0xf2ddfda2, 0xf474ef38, 0x8789bdc2, 0x5366f9c3, 0xc8b38e74, 0xb475f255, 0x46fcd9b9,
        0x7aeb2661, 0x8b1ddf84, 0x846a0e79, 0x915f95e2, 0x466e598e, 0x20b45770, 0x8cd55591, 0xc902de4c,
        0xb90bace1, 0xbb8205d0, 0x11a86248, 0x7574a99e, 0xb77f19b6, 0xe0a9dc09, 0x662d09a1, 0xc4324633,
        0xe85a1f02, 0x09f0be8c, 0x4a99a025, 0x1d6efe10, 0x1ab93d1d, 0x0ba5a4df, 0xa186f20f, 0x2868f169,
        0xdcb7da83, 0x573906fe, 0xa1e2ce9b, 0x4fcd7f52, 0x50115e01, 0xa70683fa, 0xa002b5c4, 0x0de6d027,
        0x9af88c27, 0x773f8641, 0xc3604c06, 0x61a806b5, 0xf0177a28, 0xc0f586e0, 0x006058aa, 0x30dc7d62,
        0x11e69ed7, 0x2338ea63, 0x53c2dd94, 0xc2c21634, 0xbbcbee56, 0x90bcb6de, 0xebfc7da1, 0xce591d76,
        0x6f05e409, 0x4b7c0188, 0x39720a3d, 0x7c927c24, 0x86e3725f, 0x724d9db9, 0x1ac15bb4, 0xd39eb8fc,
        0xed545578, 0x08fca5b5, 0xd83d7cd3, 0x4dad0fc4, 0x1e50ef5e, 0xb161e6f8, 0xa28514d9, 0x6c51133c,
        0x6fd5c7e7, 0x56e14ec4, 0x362abfce, 0xddc6c837, 0xd79a3234, 0x92638212, 0x670efa8e, 0x406000e0,
    ],
    [
        0x3a39ce37, 0xd3faf5cf, 0xabc27737, 0x5ac52d1b, 0x5cb0679e, 0x4fa33742, 0xd3822740, 0x99bc9bbe,
        0xd5118e9d, 0xbf0f7315, 0xd62d1c7e, 0xc700c47b, 0xb78c1b6b, 0x21a19045, 0xb26eb1be, 0x6a366eb4,
        0x5748ab2f, 0xbc946e79, 0xc6a376d2, 0x6549c2c8, 0x530ff8ee, 0x468dde7d, 0xd5730a1d, 0x4cd04dc6,
        0x2939bbdb, 0xa9ba4650, 0xac9526e8, 0xbe5ee304, 0xa1fad5f0, 0x6a2d519a, 0x63ef8ce2, 0x9a86ee22,
        0xc089c2b8, 0x43242ef6, 0xa51e03aa, 0x9cf2d0a4, 0x83c061ba, 0x9be96a4d, 0x8fe51550, 0xba645bd6,
        0x2826a2f9, 0xa73a3ae1, 0x4ba99586, 0xef5562e9, 0xc72fefd3, 0xf752f7da, 0x3f046f69, 0x77fa0a59,
        0x80e4a915, 0x87b08601, 0x9b09e6ad, 0x3b3ee593, 0xe990fd5a, 0x9e34d797, 0x2cf0b7d9, 0x022b8b51,
        0x96d5ac3a, 0x017da67d, 0xd1cf3ed6, 0x7c7d2d28, 0x1f9f25cf, 0xadf2b89b, 0x5ad6b472, 0x5a88f54c,
        0xe029ac71, 0xe019a5e6, 0x47b0acfd, 0xed93fa9b, 0xe8d3c48d, 0x283b57cc, 0xf8d56629, 0x79132e28,
        0x785f0191, 0xed756055, 0xf7960e44, 0xe3d35e8c, 0x15056dd4, 0x88f46dba, 0x03a16125, 0x0564f0bd,
        0xc3eb9e15, 0x3c9057a2, 0x97271aec, 0xa93a072a, 0x1b3f6d9b, 0x1e6321f5, 0xf59c66fb, 0x26dcf319,
        0x7533d928, 0xb155fdf5, 0x03563482, 0x8aba3cbb, 0x28517711, 0xc20ad9f8, 0xabcc5167, 0xccad925f,
        0x4de81751, 0x3830dc8e, 0x379d5862, 0x9320f991, 0xea7a90c2, 0xfb3e7bce, 0x5121ce64, 0x774fbe32,
        0xa8b6e37e, 0xc3293d46, 0x48de5369, 0x6413e680, 0xa2ae0810, 0xdd6db224, 0x69852dfd, 0x09072166,
        0xb39a460a, 0x6445c0dd, 0x586cdecf, 0x1c20c8ae, 0x5bbef7dd, 0x1b588d40, 0xccd2017f, 0x6bb4e3bb,
        0xdda26a7e, 0x3a59ff45, 0x3e350a44, 0xbcb4cdd5, 0x72eacea8, 0xfa6484bb, 0x8d6612ae, 0xbf3c6f47,
        0xd29be463, 0x542f5d9e, 0xaec2771b, 0xf64e6370, 0x740e0d8d, 0xe75b1357, 0xf8721671, 0xaf537d5d,
        0x4040cb08, 0x4eb4e2cc, 0x34d2466a, 0x0115af84, 0xe1b00428, 0x95983a1d, 0x06b89fb4, 0xce6ea048,
        0x6f3f3b82, 0x3520ab82, 0x011a1d4b, 0x277227f8, 0x611560b1, 0xe7933fdc, 0xbb3a792b, 0x344525bd,
        0xa08839e1, 0x51ce794b, 0x2f32c9b7, 0xa01fbac9, 0xe01cc87e, 0xbcc7d1f6, 0xcf0111c3, 0xa1e8aac7,
        0x1a908749, 0xd44fbd9a, 0xd0dadecb, 0xd50ada38, 0x0339c32a, 0xc6913667, 0x8df9317c, 0xe0b12b4f,
        0xf79e59b7, 0x43f5bb3a, 0xf2d519ff, 0x27d9459c, 0xbf97222c, 0x15e6fc2a, 0x0f91fc71, 0x9b941525,
        0xfae59361, 0xceb69ceb, 0xc2a86459, 0x12baa8d1, 0xb6c1075e, 0xe3056a0c, 0x10d25065, 0xcb03a442,
        0xe0ec6e0e, 0x1698db3b, 0x4c98a0be, 0x3278e964, 0x9f1f9532, 0xe0d392df, 0xd3a0342b, 0x8971f21e,
        0x1b0a7441, 0x4ba3348c, 0xc5be7120, 0xc37632d8, 0xdf359f8d, 0x9b992f2e, 0xe60b6f47, 0x0fe3f11d,
        0xe54cda54, 0x1edad891, 0xce6279cf, 0xcd3e7e6f, 0x1618b166, 0xfd2c1d05, 0x848fd2c5, 0xf6fb2299,
        0xf523f357, 0xa6327623, 0x93a83531, 0x56cccd02, 0xacf08162, 0x5a75ebb5, 0x6e163697, 0x88d273cc,
        0xde966292, 0x81b949d0, 0x4c50901b, 0x71c65614, 0xe6c6c7bd, 0x327a140a, 0x45e1d006, 0xc3f27b9a,
        0xc9aa53fd, 0x62a80f00, 0xbb25bfe2, 0x35bdd2f6, 0x71126905, 0xb2040222, 0xb6cbcf7c, 0xcd769c2b,
        0x53113ec0, 0x1640e3d3, 0x38abbd60, 0x2547adf0, 0xba38209c, 0xf746ce76, 0x77afa1c5, 0x20756060,
        0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e, 0x1948c25c, 0x02fb8a8c, 0x01c36ae4, 0xd6ebe1f9,
        0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f, 0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6,
    ],
];

#[cfg(test)]
mod tests {
    use super::bcrypt_pbkdf_sha512;

    /// Decodes a lowercase hexadecimal string into bytes for vector checks.
    ///
    /// # Arguments
    ///
    /// * `hex` - ASCII hex string with even length.
    ///
    /// # Returns
    ///
    /// Byte vector with decoded values.
    ///
    /// # Panics
    ///
    /// Panics when `hex` length is odd or includes non-hexadecimal bytes.
    fn hex_to_bytes(hex: &str) -> Vec<u8> {
        assert!(hex.len().is_multiple_of(2));
        let mut out = Vec::with_capacity(hex.len() / 2);
        for chunk in hex.as_bytes().chunks_exact(2) {
            let hi = nibble(chunk[0]);
            let lo = nibble(chunk[1]);
            out.push((hi << 4) | lo);
        }
        out
    }

    /// Converts one ASCII hexadecimal nibble into its numeric value.
    ///
    /// # Arguments
    ///
    /// * `value` - ASCII byte in `0-9`, `a-f`, or `A-F`.
    ///
    /// # Returns
    ///
    /// Nibble value in the range `0..=15`.
    ///
    /// # Panics
    ///
    /// Panics when `value` is not an ASCII hexadecimal character.
    fn nibble(value: u8) -> u8 {
        match value {
            b'0'..=b'9' => value - b'0',
            b'a'..=b'f' => value - b'a' + 10,
            b'A'..=b'F' => value - b'A' + 10,
            _ => panic!("invalid hex nibble"),
        }
    }

    #[test]
    fn bcrypt_pbkdf_vector_password_salt_round4_len32() {
        let expected =
            hex_to_bytes("5bbf0cc293587f1c3635555c27796598d47e579071bf427e9d8fbe842aba34d9");
        let derived = bcrypt_pbkdf_sha512(b"password", b"salt", 4, 32).expect("vector must derive");
        assert_eq!(derived, expected);
    }

    #[test]
    fn bcrypt_pbkdf_vector_password_salt_round8_len32() {
        let expected =
            hex_to_bytes("e17e1533acc14423155493c99b9c3bbe62ea0884207a7802e7ba72eff94d085e");
        let derived = bcrypt_pbkdf_sha512(b"password", b"salt", 8, 32).expect("vector must derive");
        assert_eq!(derived, expected);
    }

    #[test]
    fn bcrypt_pbkdf_vector_embedded_nul_round16_len48() {
        let expected = hex_to_bytes(
            "92855cdf05f666dca98681fdb6fa3a500e3a6e10e175d9aa70becd0d4ff95438d9f20375861eb34aa7606680c34f34c0",
        );
        let derived =
            bcrypt_pbkdf_sha512(b"pass\x00word", b"sa\x00lt", 16, 48).expect("vector must derive");
        assert_eq!(derived, expected);
    }

    #[test]
    fn bcrypt_pbkdf_rejects_zero_rounds() {
        let err = bcrypt_pbkdf_sha512(b"password", b"salt", 0, 32).expect_err("rounds must fail");
        assert!(matches!(err, noxtls_core::Error::InvalidLength(_)));
    }

    #[test]
    fn bcrypt_pbkdf_rejects_zero_key_length() {
        let err =
            bcrypt_pbkdf_sha512(b"password", b"salt", 4, 0).expect_err("key length must fail");
        assert!(matches!(err, noxtls_core::Error::InvalidLength(_)));
    }
}