slh_adrs.h

//  slh_adrs.h
//  Markku-Juhani O. Saarinen <mjos@iki.fi>.  See LICENSE.

//  === Internal ADRS manipulation functions (Section 4.2)

#ifndef _SLH_ADRS_H_
#define _SLH_ADRS_H_

#include "slh_param.h"
#include <string.h>

//  ADRS type constants

#define ADRS_WOTS_HASH  0
#define ADRS_WOTS_PK    1
#define ADRS_TREE       2
#define ADRS_FORS_TREE  3
#define ADRS_FORS_ROOTS 4
#define ADRS_WOTS_PRF   5
#define ADRS_FORS_PRF   6

//  Algorithm 1: toInt(x, n)

static inline uint64_t slh_toint(const uint8_t *x, unsigned n)
{
    unsigned i;
    uint64_t t;

    if (n == 0)
        return 0;
    t = (uint64_t) x[0];
    for (i = 1; i < n; i++) {
        t <<= 8;
        t += (uint64_t) x[i];
    }
    return t;
}

//  Algorithm 2: toByte(x, n)

static inline void slh_tobyte(uint8_t *x, uint64_t t, unsigned n)
{
    unsigned i;

    if (n == 0)
        return;
    for (i = n - 1; i > 0; i--) {
        x[i] = (uint8_t) (t & 0xFF);
        t >>= 8;
    }
    x[0] = (uint8_t) t;
}

//  === Clear / initialize
static inline void adrs_zero(slh_ctx_t *ctx)
{
    ctx->adrs->u32[0] = 0;
    ctx->adrs->u32[1] = 0;
    ctx->adrs->u32[2] = 0;
    ctx->adrs->u32[3] = 0;
    ctx->adrs->u32[4] = 0;
    ctx->adrs->u32[5] = 0;
    ctx->adrs->u32[6] = 0;
    ctx->adrs->u32[7] = 0;
}

//  === Set layer address.
static inline void adrs_set_layer_address(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[0] = rev8_be32(x);
}

//  === Set tree addresss.
static inline void adrs_set_tree_address(slh_ctx_t *ctx, uint64_t x)
{
    //  bytes a[4:8] of tree address are always zero
    ctx->adrs->u32[2] = rev8_be32(x >> 32);
    ctx->adrs->u32[3] = rev8_be32(x & 0xFFFFFFFF);
}

//  === Set key pair Address.
static inline void adrs_set_key_pair_address(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[5] = rev8_be32(x);
}

//  === Get key pair Address.
static inline uint32_t adrs_get_key_pair_address(const slh_ctx_t *ctx)
{
    return rev8_be32(ctx->adrs->u32[5]);
}

//  === Set FORS tree height.
static inline void adrs_set_tree_height(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[6] = rev8_be32(x);
}

//  === Set WOTS+ chain address.
static inline void adrs_set_chain_address(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[6] = rev8_be32(x);
}

//  === Set FORS tree index.
static inline void adrs_set_tree_index(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[7] = rev8_be32(x);
}

//  === Get FORS tree index.
static inline uint32_t adrs_get_tree_index(const slh_ctx_t *ctx)
{
    return rev8_be32(ctx->adrs->u32[7]);
}

//  === Set WOTS+ hash address.
static inline void adrs_set_hash_address(slh_ctx_t *ctx, uint32_t x)
{
    ctx->adrs->u32[7] = rev8_be32(x);
}

static inline void adrs_set_type(slh_ctx_t *ctx, uint32_t y)
{
    ctx->adrs->u32[4] = rev8_be32(y);
}

static inline uint32_t adrs_get_type(slh_ctx_t *ctx)
{
    return rev8_be32(ctx->adrs->u32[4]);
}

//  === "Function ADRS.setTypeAndClear(Y) for addresses sets the type
//  of the ADRS to Y and sets the final 12 bytes of the ADRS to zero."
static inline void adrs_set_type_and_clear(slh_ctx_t *ctx, uint32_t y)
{
    ctx->adrs->u32[4] = rev8_be32(y);
    ctx->adrs->u32[5] = 0;
    ctx->adrs->u32[6] = 0;
    ctx->adrs->u32[7] = 0;
}

static inline void adrs_set_type_and_clear_not_kp(slh_ctx_t *ctx, uint32_t y)
{
    ctx->adrs->u32[4] = rev8_be32(y);
    ctx->adrs->u32[6] = 0;
    ctx->adrs->u32[7] = 0;
}


//  === Compressed 22-byte address ADRSc used with SHA-2.
static inline void adrsc_22(const slh_ctx_t *ctx, uint8_t *ac)
{
    int i;
    ac[0] = ctx->adrs->u8[3];
    for (i = 0; i < 8; i++) {
        ac[i + 1] = ctx->adrs->u8[i + 8];
    }
    for (i = 0; i < 13; i++) {
        ac[i + 9] = ctx->adrs->u8[i + 19];
    }
}

//  _SLH_ADRS_H_
#endif