/*
 * Copyright (C) 2015 Southern Storm Software, Pty Ltd.
 *
 * 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.
 */

#include "BLAKE2s.h"
#include "Crypto.h"
#include "utility/EndianUtil.h"
#include "utility/RotateUtil.h"
#include "utility/ProgMemUtil.h"
#include <string.h>

/**
 * \class BLAKE2s BLAKE2s.h <BLAKE2s.h>
 * \brief BLAKE2s hash algorithm.
 *
 * BLAKE2s is a variation on the ChaCha stream cipher, designed for hashing,
 * with a 256-bit hash output.  It is intended as a high performance
 * replacement for SHA256 for when speed is critical but exact SHA256
 * compatibility is not.
 *
 * This class supports two types of keyed hash.  The BLAKE2 keyed hash and
 * traditional HMAC.  The BLAKE2 keyed hash is recommended unless there is
 * some higher-level application need to be compatible with the HMAC
 * construction.  The keyed hash is computed as follows:
 *
 * \code
 * BLAKE2s blake;
 * blake.reset(key, sizeof(key), outputLength);
 * blake.update(data1, sizeof(data1));
 * blake.update(data2, sizeof(data2));
 * ...
 * blake.update(dataN, sizeof(dataN));
 * blake.finalize(hash, outputLength);
 * \endcode
 *
 * The HMAC is computed as follows (the output length is always 32):
 *
 * \code
 * BLAKE2s blake;
 * blake.resetHMAC(key, sizeof(key));
 * blake.update(data1, sizeof(data1));
 * blake.update(data2, sizeof(data2));
 * ...
 * blake.update(dataN, sizeof(dataN));
 * blake.finalizeHMAC(key, sizeof(key), hash, 32);
 * \endcode
 *
 * References: https://blake2.net/,
 * <a href="http://tools.ietf.org/html/rfc7693">RFC 7693</a>
 *
 * \sa BLAKE2b, SHA256, SHA3_256
 */

/**
 * \brief Constructs a BLAKE2s hash object.
 */
BLAKE2s::BLAKE2s()
{
    reset();
}

/**
 * \brief Destroys this BLAKE2s hash object after clearing
 * sensitive information.
 */
BLAKE2s::~BLAKE2s()
{
    clean(state);
}

size_t BLAKE2s::hashSize() const
{
    return 32;
}

size_t BLAKE2s::blockSize() const
{
    return 64;
}

// Initialization vectors for BLAKE2s.
#define BLAKE2s_IV0 0x6A09E667
#define BLAKE2s_IV1 0xBB67AE85
#define BLAKE2s_IV2 0x3C6EF372
#define BLAKE2s_IV3 0xA54FF53A
#define BLAKE2s_IV4 0x510E527F
#define BLAKE2s_IV5 0x9B05688C
#define BLAKE2s_IV6 0x1F83D9AB
#define BLAKE2s_IV7 0x5BE0CD19

void BLAKE2s::reset()
{
    state.h[0] = BLAKE2s_IV0 ^ 0x01010020; // Default output length of 32.
    state.h[1] = BLAKE2s_IV1;
    state.h[2] = BLAKE2s_IV2;
    state.h[3] = BLAKE2s_IV3;
    state.h[4] = BLAKE2s_IV4;
    state.h[5] = BLAKE2s_IV5;
    state.h[6] = BLAKE2s_IV6;
    state.h[7] = BLAKE2s_IV7;
    state.chunkSize = 0;
    state.length = 0;
}

/**
 * \brief Resets the hash ready for a new hashing process with a specified
 * output length.
 *
 * \param outputLength The output length to use for the final hash in bytes,
 * between 1 and 32.
 */
void BLAKE2s::reset(uint8_t outputLength)
{
    if (outputLength < 1)
        outputLength = 1;
    else if (outputLength > 32)
        outputLength = 32;
    state.h[0] = BLAKE2s_IV0 ^ 0x01010000 ^ outputLength;
    state.h[1] = BLAKE2s_IV1;
    state.h[2] = BLAKE2s_IV2;
    state.h[3] = BLAKE2s_IV3;
    state.h[4] = BLAKE2s_IV4;
    state.h[5] = BLAKE2s_IV5;
    state.h[6] = BLAKE2s_IV6;
    state.h[7] = BLAKE2s_IV7;
    state.chunkSize = 0;
    state.length = 0;
}

/**
 * \brief Resets the hash ready for a new hashing process with a specified
 * key and output length.
 *
 * \param key Points to the key.
 * \param keyLen The length of the key in bytes, between 0 and 32.
 * \param outputLength The output length to use for the final hash in bytes,
 * between 1 and 32.
 *
 * If \a keyLen is greater than 32, then the \a key will be truncated to
 * the first 32 bytes.
 */
void BLAKE2s::reset(const void *key, size_t keyLen, uint8_t outputLength)
{
    if (keyLen > 32)
        keyLen = 32;
    if (outputLength < 1)
        outputLength = 1;
    else if (outputLength > 32)
        outputLength = 32;
    state.h[0] = BLAKE2s_IV0 ^ 0x01010000 ^ (keyLen << 8) ^ outputLength;
    state.h[1] = BLAKE2s_IV1;
    state.h[2] = BLAKE2s_IV2;
    state.h[3] = BLAKE2s_IV3;
    state.h[4] = BLAKE2s_IV4;
    state.h[5] = BLAKE2s_IV5;
    state.h[6] = BLAKE2s_IV6;
    state.h[7] = BLAKE2s_IV7;
    if (keyLen > 0) {
        // Set the first block to the key and pad with zeroes.
        memcpy(state.m, key, keyLen);
        memset(((uint8_t *)state.m) + keyLen, 0, 64 - keyLen);
        state.chunkSize = 64;
        state.length = 64;
    } else {
        // No key.  The first data block is the first hashed block.
        state.chunkSize = 0;
        state.length = 0;
    }
}

void BLAKE2s::update(const void *data, size_t len)
{
    // Break the input up into 512-bit chunks and process each in turn.
    const uint8_t *d = (const uint8_t *)data;
    while (len > 0) {
        if (state.chunkSize == 64) {
            // Previous chunk was full and we know that it wasn't the
            // last chunk, so we can process it now with f0 set to zero.
            processChunk(0);
            state.chunkSize = 0;
        }
        uint8_t size = 64 - state.chunkSize;
        if (size > len)
            size = len;
        memcpy(((uint8_t *)state.m) + state.chunkSize, d, size);
        state.chunkSize += size;
        state.length += size;
        len -= size;
        d += size;
    }
}

void BLAKE2s::finalize(void *hash, size_t len)
{
    // Pad the last chunk and hash it with f0 set to all-ones.
    memset(((uint8_t *)state.m) + state.chunkSize, 0, 64 - state.chunkSize);
    processChunk(0xFFFFFFFF);

    // Convert the hash into little-endian in the message buffer.
    for (uint8_t posn = 0; posn < 8; ++posn)
        state.m[posn] = htole32(state.h[posn]);

    // Copy the hash to the caller's return buffer.
    if (len > 32)
        len = 32;
    memcpy(hash, state.m, len);
}

void BLAKE2s::clear()
{
    clean(state);
    reset();
}

void BLAKE2s::resetHMAC(const void *key, size_t keyLen)
{
    formatHMACKey(state.m, key, keyLen, 0x36);
    state.length += 64;
    processChunk(0);
}

void BLAKE2s::finalizeHMAC(const void *key, size_t keyLen, void *hash, size_t hashLen)
{
    uint8_t temp[32];
    finalize(temp, sizeof(temp));
    formatHMACKey(state.m, key, keyLen, 0x5C);
    state.length += 64;
    processChunk(0);
    update(temp, sizeof(temp));
    finalize(hash, hashLen);
    clean(temp);
}

// Permutation on the message input state for BLAKE2s.
static const uint8_t sigma[10][16] PROGMEM = {
    { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15},
    {14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3},
    {11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4},
    { 7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8},
    { 9,  0,  5,  7,  2,  4, 10, 15, 14,  1, 11, 12,  6,  8,  3, 13},
    { 2, 12,  6, 10,  0, 11,  8,  3,  4, 13,  7,  5, 15, 14,  1,  9},
    {12,  5,  1, 15, 14, 13,  4, 10,  0,  7,  6,  3,  9,  2,  8, 11},
    {13, 11,  7, 14, 12,  1,  3,  9,  5,  0, 15,  4,  8,  6,  2, 10},
    { 6, 15, 14,  9, 11,  3,  0,  8, 12,  2, 13,  7,  1,  4, 10,  5},
    {10,  2,  8,  4,  7,  6,  1,  5, 15, 11,  9, 14,  3, 12, 13 , 0}
};

// Perform a BLAKE2s quarter round operation.
#define quarterRound(a, b, c, d, i)    \
    do { \
        uint32_t _b = (b); \
        uint32_t _a = (a) + _b + state.m[pgm_read_byte(&(sigma[index][2 * (i)]))]; \
        uint32_t _d = rightRotate16((d) ^ _a); \
        uint32_t _c = (c) + _d; \
        _b = rightRotate12(_b ^ _c); \
        _a += _b + state.m[pgm_read_byte(&(sigma[index][2 * (i) + 1]))]; \
        (d) = _d = rightRotate8(_d ^ _a); \
        _c += _d; \
        (a) = _a; \
        (b) = rightRotate7(_b ^ _c); \
        (c) = _c; \
    } while (0)

void BLAKE2s::processChunk(uint32_t f0)
{
    uint8_t index;
    uint32_t v[16];

    // Byte-swap the message buffer into little-endian if necessary.
#if !defined(CRYPTO_LITTLE_ENDIAN)
    for (index = 0; index < 16; ++index)
        state.m[index] = le32toh(state.m[index]);
#endif

    // Format the block to be hashed.
    memcpy(v, state.h, sizeof(state.h));
    v[8]  = BLAKE2s_IV0;
    v[9]  = BLAKE2s_IV1;
    v[10] = BLAKE2s_IV2;
    v[11] = BLAKE2s_IV3;
    v[12] = BLAKE2s_IV4 ^ (uint32_t)(state.length);
    v[13] = BLAKE2s_IV5 ^ (uint32_t)(state.length >> 32);
    v[14] = BLAKE2s_IV6 ^ f0;
    v[15] = BLAKE2s_IV7;

    // Perform the 10 BLAKE2s rounds.
    for (index = 0; index < 10; ++index) {
        // Column round.
        quarterRound(v[0], v[4], v[8],  v[12], 0);
        quarterRound(v[1], v[5], v[9],  v[13], 1);
        quarterRound(v[2], v[6], v[10], v[14], 2);
        quarterRound(v[3], v[7], v[11], v[15], 3);

        // Diagonal round.
        quarterRound(v[0], v[5], v[10], v[15], 4);
        quarterRound(v[1], v[6], v[11], v[12], 5);
        quarterRound(v[2], v[7], v[8],  v[13], 6);
        quarterRound(v[3], v[4], v[9],  v[14], 7);
    }

    // Combine the new and old hash values.
    for (index = 0; index < 8; ++index)
        state.h[index] ^= (v[index] ^ v[index + 8]);
}