Commit 6bfc8529 authored by mattcampagna's avatar mattcampagna
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Adding initial commitment of qshkex.c, qshkex.h and main.c of reference implementation.

parent de021c0c

main.c

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qshkex.c

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/*

    This file implements ETSI TC CYBER QSC Quantum-safe Hybrid Key Exchanges

    (Version 1.1.1)



    This is not intended for production use.  It is intended to be a reference

    implementation for test vectors for the specification.



    It uses OpenSSL version 1.1.1d libcrypto.



    gcc -Wall -o etsi-hkex-test main.c qshkex.c -lcrypto

    ./etsi-hkex-test



    Copyright 2020 ETSI. All rights reserved

    SPDX-License-Identifier: BSD-3-Clause

*/



#include "qshkex.h"



/* Memory helper functions to handle null values */

static inline void *my_memcpy(void *dst, const void *src, size_t byte_len)

{

    if (src == NULL || dst == NULL) {

        return dst;

    }

    return memcpy(dst, src, byte_len);

}



/*  Implements the kdf context formatting function f, see Section 7.2  */

int f_function(const EVP_MD *md_type, uint8_t *kdf_context, uint32_t *clength, const uint8_t *arg1,

               const uint32_t a1length, const uint8_t *arg2, const uint32_t a2length, const uint8_t *arg3,

               const uint32_t a3length)

{

    int         rval = FAILURE;

    uint32_t    length;

    EVP_MD_CTX *mdctx = NULL;



    do {

        if ((md_type == NULL) || (kdf_context == NULL) || (clength == NULL)) {

            break;

        }

        if (((a1length) && (arg1 == NULL)) || ((a2length) && (arg2 == NULL)) || ((a3length) && (arg3 == NULL))) {

            break;

        }

        if ((mdctx = EVP_MD_CTX_new()) == NULL) {

            break;

        }

        if (EVP_DigestInit(mdctx, md_type) != 1) {

            break;

        }

        length = htonl(a1length);

        if (EVP_DigestUpdate(mdctx, &length, sizeof(length)) != 1) {

            break;

        }

        if (EVP_DigestUpdate(mdctx, arg1, a1length) != 1) {

            break;

        }

        length = htonl(a2length);

        if (EVP_DigestUpdate(mdctx, &length, sizeof(length)) != 1) {

            break;

        }

        if (EVP_DigestUpdate(mdctx, arg2, a2length) != 1) {

            break;

        }

        length = htonl(a3length);

        if (EVP_DigestUpdate(mdctx, &length, sizeof(length)) != 1) {

            break;

        }

        if (EVP_DigestUpdate(mdctx, arg3, a3length) != 1) {

            break;

        }

        if (EVP_DigestFinal_ex(mdctx, kdf_context, clength) != 1) {

            break;

        }

        rval = SUCCESS;

    } while (0);

    if (mdctx) {

        EVP_MD_CTX_free(mdctx);

    }

    return rval;

}

/*  Implements the HMAC prf function from Section 7.3.2  */

int prf_hmac(const EVP_MD *md_type, uint8_t *output, uint32_t *olength, const uint8_t *secret, const uint8_t slength,

             const uint8_t *ki, const uint32_t kilength, const uint8_t *MAi, const uint32_t mailength,

             const uint8_t *MBi, const uint32_t mbilength)

{

    int         rval    = FAILURE;

    uint32_t    clength = MAX_DIGEST_BYTE_LEN;

    uint8_t     context[MAX_DIGEST_BYTE_LEN];

    size_t      outlen = MAX_DIGEST_BYTE_LEN;

    EVP_MD_CTX *mdctx  = NULL;

    EVP_PKEY *  pkey   = NULL;



    do {

        if ((md_type == NULL) || (output == NULL) || (olength == NULL)) {

            break;

        }

        if (((slength) && (secret == NULL)) || ((kilength) && (ki == NULL))) {

            break;

        }

        if (((mailength) && (MAi == NULL)) || ((mbilength) && (MBi == NULL))) {

            break;

        }

        if (f_function(md_type, context, &clength, ki, kilength, MAi, mailength, MBi, mbilength)) {

            break;

        }

        if ((mdctx = EVP_MD_CTX_new()) == NULL) {

            break;

        }

        if ((pkey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, secret, slength)) == NULL) {

            break;

        }

        if (EVP_DigestSignInit(mdctx, NULL, md_type, NULL, pkey) != 1) {

            break;

        }

        if (EVP_DigestSignUpdate(mdctx, context, clength) != 1) {

            break;

        }

        outlen = *olength;

        if (EVP_DigestSignFinal(mdctx, output, &outlen) != 1) {

            break;

        }

        *olength = (uint32_t)outlen;

        rval     = SUCCESS;

    } while (0);

    if (mdctx) {

        EVP_MD_CTX_free(mdctx);

    }

    if (pkey) {

        EVP_PKEY_free(pkey);

    }

    return rval;

}

/*  Implements the HMAC KDF function from Section 7.4.2   */

int kdf(const EVP_MD *md_type, uint8_t *key_material, uint32_t *klength, const uint8_t *secret, const uint32_t slength,

        const uint8_t *label, const uint32_t llength, const uint8_t *context, const uint32_t clength)

{

    int           rval = FAILURE;

    EVP_PKEY_CTX *pctx = NULL;

    size_t        keylen;



    do {

        if ((md_type == NULL) || (key_material == NULL) || (klength == NULL) || (secret == NULL)) {

            break;

        }

        if (((llength) && (label == NULL)) || ((clength) && (context == NULL))) {

            break;

        }

        if ((pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL)) == NULL) {

            break;

        }

        if (EVP_PKEY_derive_init(pctx) != 1) {

            break;

        }

        if (EVP_PKEY_CTX_set_hkdf_md(pctx, md_type) != 1) {

            break;

        }

        if (EVP_PKEY_CTX_set1_hkdf_salt(pctx, label, (int)llength) != 1) {

            break;

        }

        if (EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, (int)slength) != 1) {

            break;

        }

        if (EVP_PKEY_CTX_add1_hkdf_info(pctx, context, (int)clength) != 1) {

            break;

        }

        keylen = *klength;

        if (EVP_PKEY_derive(pctx, key_material, &keylen) != 1) {

            break;

        }

        *klength = (uint32_t)keylen;

        rval     = SUCCESS;

    } while (0);

    if (pctx) {

        EVP_PKEY_CTX_free(pctx);

    }

    return rval;

}

/*  Implements the function Concatenation KDF from Section 8.2   */

int hkex_concat(const EVP_MD *md_type, uint8_t *key_material, const uint32_t klength, const uint8_t *psk,

                const uint32_t plength, const uint8_t *k1, const uint32_t k1length, const uint8_t *k2,

                const uint32_t k2length, const uint8_t *MA, const uint32_t malength, const uint8_t *MB,

                const uint32_t mblength, const uint8_t *context, const uint32_t clength, const uint8_t *label,

                const uint32_t llength)

{

    int      rval = FAILURE;

    uint8_t  secrets[MAX_SECRETS_BYTE_LEN];

    uint8_t  kdf_context[MAX_DIGEST_BYTE_LEN];

    uint32_t kmlength, slength, kdfclength;

    uint64_t total_size;

    do {

        if ((md_type == NULL) || (key_material == NULL) || (k1 == NULL) || (k2 == NULL) || (MA == NULL) ||

            (MB == NULL)) {

            break;

        }

        if (((llength) && (label == NULL)) || ((clength) && (context == NULL)) || ((plength) && (psk == NULL))) {

            break;

        }

        total_size = plength + k1length + k2length;

        if (total_size > MAX_SECRETS_BYTE_LEN) {

            break;

        }

        kdfclength = MAX_DIGEST_BYTE_LEN;

        if (f_function(md_type, kdf_context, &kdfclength, context, clength, MA, malength, MB, mblength)) {

            break;

        }

        my_memcpy(secrets, psk, plength);

        my_memcpy(secrets + plength, k1, k1length);

        my_memcpy(secrets + plength + k1length, k2, k2length);

        slength  = plength + k1length + k2length;

        kmlength = klength;

        if (kdf(md_type, key_material, &kmlength, secrets, slength, label, llength, kdf_context, kdfclength)) {

            break;

        }

        rval = SUCCESS;

    } while (0);

    return rval;

}

/* Implements the one round of the function Cascading KDF from Section 8.3 */

int hkex_cascade(const EVP_MD *md_type, uint8_t *chain_secret, const uint32_t cslength, uint8_t *key_material,

                 const uint32_t klength, const uint8_t *previous_chain_secret, const uint32_t pcslength,

                 const uint8_t *ki, const uint32_t kilength, const uint8_t *MAi, const uint32_t mailength,

                 const uint8_t *MBi, const uint32_t mbilength, const uint8_t *contexti, const uint32_t cilength,

                 const uint8_t *labeli, const uint32_t lilength)

{

    int      rval = FAILURE;

    uint8_t  rsecret[MAX_DIGEST_BYTE_LEN];

    uint8_t  output[MAX_KEY_MATERIAL_BYTE_LEN + MAX_DIGEST_BYTE_LEN];

    uint32_t olength, rlength = MAX_DIGEST_BYTE_LEN;

    uint64_t osize;



    do {

        if ((md_type == NULL) || (chain_secret == NULL) || (key_material == NULL) || (ki == NULL) || (MAi == NULL) ||

            (MBi == NULL)) {

            break;

        }

        if (((pcslength) && (previous_chain_secret == NULL)) || ((cilength) && (contexti == NULL)) ||

            ((lilength) && (labeli == NULL))) {

            break;

        }

        if ((cslength > MAX_DIGEST_BYTE_LEN) || (klength > MAX_KEY_MATERIAL_BYTE_LEN)) {

            break;

        }

        osize = cslength + klength;

        if (osize > sizeof(output)) {

            break;

        }

        if (prf_hmac(md_type, rsecret, &rlength, previous_chain_secret, pcslength, ki, kilength, MAi, mailength, MBi,

                     mbilength)) {

            break;

        }

        olength = (uint32_t)osize;

        if (kdf(md_type, output, &olength, rsecret, rlength, labeli, lilength, contexti, cilength)) {

            break;

        }

        if (olength != (uint32_t)osize) {

            break;

        }

        my_memcpy(chain_secret, output, cslength);

        my_memcpy(key_material, output + cslength, klength);

        OPENSSL_cleanse(output, sizeof(output));

        rval = SUCCESS;

    } while (0);

    return rval;

}

qshkex.h

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/*

    Header file for a reference implementation of

    ETSI TC CYBER QSC Quantum-safe Hybrid Key Exchanges (Version 1.1.1)



    This is not intended for production use.  It is intended to be a reference

    implementation for test vectors for the specification.



    Copyright 2020 ETSI. All rights reserved

    SPDX-License-Identifier: BSD-3-Clause

*/



#ifndef _QS_H_KEX_H_

#define _QS_H_KEX_H_



#include <arpa/inet.h>

#include <openssl/crypto.h>

#include <openssl/evp.h>

#include <openssl/kdf.h>

#include <openssl/sha.h>

#include <stdio.h>

#include <string.h>



#define SUCCESS                   (0)

#define FAILURE                   (-1)

#define MAX_DIGEST_BYTE_LEN       64

#define MAX_SECRETS_BYTE_LEN      256

#define MAX_KEY_MATERIAL_BYTE_LEN 128



void print_array(const char *label, const uint8_t *array, const uint32_t alength);



int hkex_concat(const EVP_MD *md_type, uint8_t *key_material, const uint32_t klength, const uint8_t *psk,

                const uint32_t plength, const uint8_t *k1, const uint32_t k1length, const uint8_t *k2,

                const uint32_t k2length, const uint8_t *MA, const uint32_t malength, const uint8_t *MB,

                const uint32_t mblength, const uint8_t *context, const uint32_t clength, const uint8_t *label,

                const uint32_t llength);



int hkex_cascade(const EVP_MD *md_type, uint8_t *chain_secret, const uint32_t cslength, uint8_t *key_material,

                 const uint32_t klength, const uint8_t *previous_chain_secret, const uint32_t pcslength,

                 const uint8_t *ki, const uint32_t kilength, const uint8_t *MAi, const uint32_t mailength,

                 const uint8_t *MBi, const uint32_t mbilength, const uint8_t *contexti, const uint32_t cilength,

                 const uint8_t *labeli, const uint32_t lilength);



#endif /*_QS_H_KEX_H_*/