From 9e7e4ab6617fef1d1681fc2d3e02554264ccc954 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 13:13:18 +0200 Subject: Adding upstream version 1:8.4p1. Signed-off-by: Daniel Baumann --- xmss_wots.c | 192 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 xmss_wots.c (limited to 'xmss_wots.c') diff --git a/xmss_wots.c b/xmss_wots.c new file mode 100644 index 0000000..993e661 --- /dev/null +++ b/xmss_wots.c @@ -0,0 +1,192 @@ +/* $OpenBSD: xmss_wots.c,v 1.3 2018/04/10 00:10:49 djm Exp $ */ +/* +wots.c version 20160722 +Andreas Hülsing +Joost Rijneveld +Public domain. +*/ + +#include "includes.h" +#ifdef WITH_XMSS + +#include +#ifdef HAVE_STDINT_H +# include +#endif +#include +#include "xmss_commons.h" +#include "xmss_hash.h" +#include "xmss_wots.h" +#include "xmss_hash_address.h" + + +/* libm-free version of log2() for wots */ +static inline int +wots_log2(uint32_t v) +{ + int b; + + for (b = sizeof (v) * CHAR_BIT - 1; b >= 0; b--) { + if ((1U << b) & v) { + return b; + } + } + return 0; +} + +void +wots_set_params(wots_params *params, int n, int w) +{ + params->n = n; + params->w = w; + params->log_w = wots_log2(params->w); + params->len_1 = (CHAR_BIT * n) / params->log_w; + params->len_2 = (wots_log2(params->len_1 * (w - 1)) / params->log_w) + 1; + params->len = params->len_1 + params->len_2; + params->keysize = params->len * params->n; +} + +/** + * Helper method for pseudorandom key generation + * Expands an n-byte array into a len*n byte array + * this is done using PRF + */ +static void expand_seed(unsigned char *outseeds, const unsigned char *inseed, const wots_params *params) +{ + uint32_t i = 0; + unsigned char ctr[32]; + for(i = 0; i < params->len; i++){ + to_byte(ctr, i, 32); + prf((outseeds + (i*params->n)), ctr, inseed, params->n); + } +} + +/** + * Computes the chaining function. + * out and in have to be n-byte arrays + * + * interprets in as start-th value of the chain + * addr has to contain the address of the chain + */ +static void gen_chain(unsigned char *out, const unsigned char *in, unsigned int start, unsigned int steps, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]) +{ + uint32_t i, j; + for (j = 0; j < params->n; j++) + out[j] = in[j]; + + for (i = start; i < (start+steps) && i < params->w; i++) { + setHashADRS(addr, i); + hash_f(out, out, pub_seed, addr, params->n); + } +} + +/** + * base_w algorithm as described in draft. + * + * + */ +static void base_w(int *output, const int out_len, const unsigned char *input, const wots_params *params) +{ + int in = 0; + int out = 0; + uint32_t total = 0; + int bits = 0; + int consumed = 0; + + for (consumed = 0; consumed < out_len; consumed++) { + if (bits == 0) { + total = input[in]; + in++; + bits += 8; + } + bits -= params->log_w; + output[out] = (total >> bits) & (params->w - 1); + out++; + } +} + +void wots_pkgen(unsigned char *pk, const unsigned char *sk, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]) +{ + uint32_t i; + expand_seed(pk, sk, params); + for (i=0; i < params->len; i++) { + setChainADRS(addr, i); + gen_chain(pk+i*params->n, pk+i*params->n, 0, params->w-1, params, pub_seed, addr); + } +} + + +int wots_sign(unsigned char *sig, const unsigned char *msg, const unsigned char *sk, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]) +{ + //int basew[params->len]; + int csum = 0; + uint32_t i = 0; + int *basew = calloc(params->len, sizeof(int)); + if (basew == NULL) + return -1; + + base_w(basew, params->len_1, msg, params); + + for (i=0; i < params->len_1; i++) { + csum += params->w - 1 - basew[i]; + } + + csum = csum << (8 - ((params->len_2 * params->log_w) % 8)); + + int len_2_bytes = ((params->len_2 * params->log_w) + 7) / 8; + + unsigned char csum_bytes[len_2_bytes]; + to_byte(csum_bytes, csum, len_2_bytes); + + int csum_basew[params->len_2]; + base_w(csum_basew, params->len_2, csum_bytes, params); + + for (i = 0; i < params->len_2; i++) { + basew[params->len_1 + i] = csum_basew[i]; + } + + expand_seed(sig, sk, params); + + for (i = 0; i < params->len; i++) { + setChainADRS(addr, i); + gen_chain(sig+i*params->n, sig+i*params->n, 0, basew[i], params, pub_seed, addr); + } + free(basew); + return 0; +} + +int wots_pkFromSig(unsigned char *pk, const unsigned char *sig, const unsigned char *msg, const wots_params *params, const unsigned char *pub_seed, uint32_t addr[8]) +{ + int csum = 0; + uint32_t i = 0; + int *basew = calloc(params->len, sizeof(int)); + if (basew == NULL) + return -1; + + base_w(basew, params->len_1, msg, params); + + for (i=0; i < params->len_1; i++) { + csum += params->w - 1 - basew[i]; + } + + csum = csum << (8 - ((params->len_2 * params->log_w) % 8)); + + int len_2_bytes = ((params->len_2 * params->log_w) + 7) / 8; + + unsigned char csum_bytes[len_2_bytes]; + to_byte(csum_bytes, csum, len_2_bytes); + + int csum_basew[params->len_2]; + base_w(csum_basew, params->len_2, csum_bytes, params); + + for (i = 0; i < params->len_2; i++) { + basew[params->len_1 + i] = csum_basew[i]; + } + for (i=0; i < params->len; i++) { + setChainADRS(addr, i); + gen_chain(pk+i*params->n, sig+i*params->n, basew[i], params->w-1-basew[i], params, pub_seed, addr); + } + free(basew); + return 0; +} +#endif /* WITH_XMSS */ -- cgit v1.2.3