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/*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "exdsa_ecdhkem.h"
#include <botan/secmem.h>
#include <botan/pubkey.h>
#include <botan/bigint.h>
#include <botan/ec_group.h>
#include <botan/ecdh.h>
#include <botan/ecdsa.h>
#include <botan/ed25519.h>
#include <botan/x25519.h>
#if defined(ENABLE_CRYPTO_REFRESH)
#include <botan/x448.h>
#include <botan/ed448.h>
#endif
#include "ecdh.h"
#include "ed25519_ed448.h"
#include "ecdsa.h"
#include "ec.h"
#include "types.h"
#include "logging.h"
#include "string.h"
#include "utils.h"
#include <cassert>
#include <botan/ec_group.h>
ec_key_t::~ec_key_t()
{
}
ec_key_t::ec_key_t(pgp_curve_t curve) : curve_(curve)
{
}
ecdh_kem_public_key_t::ecdh_kem_public_key_t(uint8_t * key_buf,
size_t key_buf_len,
pgp_curve_t curve)
: ec_key_t(curve), key_(std::vector<uint8_t>(key_buf, key_buf + key_buf_len))
{
}
ecdh_kem_public_key_t::ecdh_kem_public_key_t(std::vector<uint8_t> key, pgp_curve_t curve)
: ec_key_t(curve), key_(key)
{
}
ecdh_kem_private_key_t::ecdh_kem_private_key_t(uint8_t * key_buf,
size_t key_buf_len,
pgp_curve_t curve)
: ec_key_t(curve), key_(key_buf, key_buf + key_buf_len)
{
}
ecdh_kem_private_key_t::ecdh_kem_private_key_t(std::vector<uint8_t> key, pgp_curve_t curve)
: ec_key_t(curve), key_(std::move(key))
{
}
static Botan::ECDH_PrivateKey
ecdh_kem_privkey_from_bytes(rnp::RNG * rng,
const uint8_t *key_data,
size_t key_size,
pgp_curve_t curve)
{
assert(curve >= PGP_CURVE_NIST_P_256 && curve <= PGP_CURVE_P256K1);
auto ec_desc = pgp::ec::Curve::get(curve);
return Botan::ECDH_PrivateKey(*(rng->obj()),
Botan::EC_Group::from_name(ec_desc->botan_name),
Botan::BigInt(key_data, key_size));
}
static Botan::ECDH_PublicKey
ecdh_kem_pubkey_from_bytes(rnp::RNG *rng, const std::vector<uint8_t> &key, pgp_curve_t curve)
{
assert(curve >= PGP_CURVE_NIST_P_256 && curve <= PGP_CURVE_P256K1);
auto ec_desc = pgp::ec::Curve::get(curve);
Botan::EC_Group group = Botan::EC_Group::from_name(ec_desc->botan_name);
return Botan::ECDH_PublicKey(group, Botan::EC_AffinePoint(group, key).to_legacy_point());
}
static Botan::X25519_PrivateKey
x25519_privkey_from_bytes(const uint8_t *key_data, size_t key_size)
{
Botan::secure_vector<uint8_t> sv(key_data, key_data + key_size);
return Botan::X25519_PrivateKey(sv);
}
static Botan::X25519_PublicKey
x25519_pubkey_from_bytes(const std::vector<uint8_t> &key)
{
return Botan::X25519_PublicKey(key);
}
#if defined(ENABLE_CRYPTO_REFRESH)
static Botan::X448_PrivateKey
x448_privkey_from_bytes(const uint8_t *key_data, size_t key_size)
{
Botan::secure_vector<uint8_t> sv(key_data, key_data + key_size);
return Botan::X448_PrivateKey(sv);
}
static Botan::X448_PublicKey
x448_pubkey_from_bytes(const std::vector<uint8_t> &key)
{
return Botan::X448_PublicKey(key);
}
#endif
std::vector<uint8_t>
ecdh_kem_private_key_t::get_pubkey_encoded(rnp::RNG *rng) const
{
switch (curve_) {
case PGP_CURVE_25519: {
Botan::X25519_PrivateKey botan_key =
x25519_privkey_from_bytes(key_.data(), key_.size());
return botan_key.public_value();
}
#if defined(ENABLE_CRYPTO_REFRESH)
case PGP_CURVE_448: {
Botan::X448_PrivateKey botan_key = x448_privkey_from_bytes(key_.data(), key_.size());
return botan_key.public_value();
}
#endif
default: {
Botan::ECDH_PrivateKey botan_key =
ecdh_kem_privkey_from_bytes(rng, key_.data(), key_.size(), curve_);
return botan_key.public_value();
}
}
}
rnp_result_t
ecdh_kem_public_key_t::encapsulate(rnp::RNG * rng,
std::vector<uint8_t> &ciphertext,
std::vector<uint8_t> &symmetric_key) const
{
switch (curve_) {
case PGP_CURVE_25519: {
Botan::X25519_PrivateKey eph_prv_key(*(rng->obj()));
ciphertext = eph_prv_key.public_value();
Botan::PK_Key_Agreement key_agreement(eph_prv_key, *(rng->obj()), "Raw");
symmetric_key = Botan::unlock(key_agreement.derive_key(0, key_).bits_of());
break;
}
#if defined(ENABLE_CRYPTO_REFRESH)
case PGP_CURVE_448: {
Botan::X448_PrivateKey eph_prv_key(*(rng->obj()));
ciphertext = eph_prv_key.public_value();
Botan::PK_Key_Agreement key_agreement(eph_prv_key, *(rng->obj()), "Raw");
symmetric_key = Botan::unlock(key_agreement.derive_key(0, key_).bits_of());
break;
}
#endif
default: {
auto curve_desc = pgp::ec::Curve::get(curve_);
if (!curve_desc) {
RNP_LOG("unknown curve");
return RNP_ERROR_NOT_SUPPORTED;
}
Botan::EC_Group domain = Botan::EC_Group::from_name(curve_desc->botan_name);
Botan::ECDH_PrivateKey eph_prv_key(*(rng->obj()), domain);
Botan::PK_Key_Agreement key_agreement(eph_prv_key, *(rng->obj()), "Raw");
ciphertext = eph_prv_key.public_value();
symmetric_key = Botan::unlock(key_agreement.derive_key(0, key_).bits_of());
break;
}
}
return RNP_SUCCESS;
}
rnp_result_t
ecdh_kem_private_key_t::decapsulate(rnp::RNG * rng,
const std::vector<uint8_t> &ciphertext,
std::vector<uint8_t> & plaintext)
{
switch (curve_) {
case PGP_CURVE_25519: {
Botan::X25519_PrivateKey priv_key =
x25519_privkey_from_bytes(key_.data(), key_.size());
Botan::PK_Key_Agreement key_agreement(priv_key, *(rng->obj()), "Raw");
plaintext = Botan::unlock(key_agreement.derive_key(0, ciphertext).bits_of());
break;
}
#if defined(ENABLE_CRYPTO_REFRESH)
case PGP_CURVE_448: {
Botan::X448_PrivateKey priv_key = x448_privkey_from_bytes(key_.data(), key_.size());
Botan::PK_Key_Agreement key_agreement(priv_key, *(rng->obj()), "Raw");
plaintext = Botan::unlock(key_agreement.derive_key(0, ciphertext).bits_of());
break;
}
#endif
default: {
Botan::ECDH_PrivateKey priv_key =
ecdh_kem_privkey_from_bytes(rng, key_.data(), key_.size(), curve_);
Botan::PK_Key_Agreement key_agreement(priv_key, *(rng->obj()), "Raw");
plaintext = Botan::unlock(key_agreement.derive_key(0, ciphertext).bits_of());
break;
}
}
return RNP_SUCCESS;
}
rnp_result_t
ec_key_t::generate_ecdh_kem_key_pair(rnp::RNG *rng, ecdh_kem_key_t *out, pgp_curve_t curve)
{
std::vector<uint8_t> pub, priv;
rnp_result_t result = ec_generate_native(rng, priv, pub, curve);
if (result != RNP_SUCCESS) {
RNP_LOG("error when generating EC key pair");
return result;
}
out->priv = ecdh_kem_private_key_t(priv, curve);
out->pub = ecdh_kem_public_key_t(pub, curve);
return RNP_SUCCESS;
}
#if defined(ENABLE_CRYPTO_REFRESH)
exdsa_public_key_t::exdsa_public_key_t(uint8_t *key_buf, size_t key_buf_len, pgp_curve_t curve)
: ec_key_t(curve), key_(key_buf, key_buf + key_buf_len)
{
}
exdsa_public_key_t::exdsa_public_key_t(std::vector<uint8_t> key, pgp_curve_t curve)
: ec_key_t(curve), key_(key)
{
}
exdsa_private_key_t::exdsa_private_key_t(uint8_t * key_buf,
size_t key_buf_len,
pgp_curve_t curve)
: ec_key_t(curve), key_(key_buf, key_buf + key_buf_len)
{
}
exdsa_private_key_t::exdsa_private_key_t(std::vector<uint8_t> key, pgp_curve_t curve)
: ec_key_t(curve), key_(std::move(key))
{
}
rnp_result_t
ec_key_t::generate_exdsa_key_pair(rnp::RNG *rng, exdsa_key_t *out, pgp_curve_t curve)
{
std::vector<uint8_t> pub, priv;
rnp_result_t result = ec_generate_native(rng, priv, pub, curve);
if (result != RNP_SUCCESS) {
RNP_LOG("error when generating EC key pair");
return result;
}
out->priv = exdsa_private_key_t(priv, curve);
out->pub = exdsa_public_key_t(pub, curve);
return RNP_SUCCESS;
}
static Botan::ECDSA_PrivateKey
exdsa_privkey_from_bytes(rnp::RNG * rng,
const uint8_t *key_data,
size_t key_size,
pgp_curve_t curve)
{
auto ec_desc = pgp::ec::Curve::get(curve);
return Botan::ECDSA_PrivateKey(*(rng->obj()),
Botan::EC_Group::from_name(ec_desc->botan_name),
Botan::BigInt(key_data, key_size));
}
static Botan::ECDSA_PublicKey
exdsa_pubkey_from_bytes(const std::vector<uint8_t> &key, pgp_curve_t curve)
{
/* format: 04 | X | Y */
auto ec_desc = pgp::ec::Curve::get(curve);
Botan::EC_Group group = Botan::EC_Group::from_name(ec_desc->botan_name);
return Botan::ECDSA_PublicKey(group, Botan::EC_AffinePoint(group, key).to_legacy_point());
}
/* NOTE hash_alg unused for Ed/X curves */
rnp_result_t
exdsa_private_key_t::sign(rnp::RNG * rng,
std::vector<uint8_t> &sig_out,
const uint8_t * hash,
size_t hash_len,
pgp_hash_alg_t hash_alg) const
{
switch (curve_) {
case PGP_CURVE_ED25519: {
return ed25519_sign_native(rng, sig_out, key_.unlock(), hash, hash_len);
}
case PGP_CURVE_ED448: {
return ed448_sign_native(rng, sig_out, key_.unlock(), hash, hash_len);
}
default: {
Botan::ECDSA_PrivateKey priv_key =
exdsa_privkey_from_bytes(rng, key_.data(), key_.size(), curve_);
auto signer =
Botan::PK_Signer(priv_key, *(rng->obj()), pgp::ecdsa::padding_str_for(hash_alg));
sig_out = signer.sign_message(hash, hash_len, *(rng->obj()));
return RNP_SUCCESS;
}
}
}
rnp_result_t
exdsa_public_key_t::verify(const std::vector<uint8_t> &sig,
const uint8_t * hash,
size_t hash_len,
pgp_hash_alg_t hash_alg) const
{
switch (curve_) {
case PGP_CURVE_ED25519: {
return ed25519_verify_native(sig, key_, hash, hash_len);
}
case PGP_CURVE_ED448: {
return ed448_verify_native(sig, key_, hash, hash_len);
}
default: {
Botan::ECDSA_PublicKey pub_key = exdsa_pubkey_from_bytes(key_, curve_);
auto verifier = Botan::PK_Verifier(pub_key, pgp::ecdsa::padding_str_for(hash_alg));
if (verifier.verify_message(hash, hash_len, sig.data(), sig.size())) {
return RNP_SUCCESS;
}
}
}
return RNP_ERROR_VERIFICATION_FAILED;
}
bool
exdsa_public_key_t::is_valid(rnp::RNG *rng) const
{
switch (curve_) {
case PGP_CURVE_ED25519: {
Botan::Ed25519_PublicKey pub_key(key_);
return pub_key.check_key(*(rng->obj()), false);
}
case PGP_CURVE_ED448: {
Botan::Ed448_PublicKey pub_key(key_);
return pub_key.check_key(*(rng->obj()), false);
}
default: {
Botan::ECDSA_PublicKey pub_key = exdsa_pubkey_from_bytes(key_, curve_);
return pub_key.check_key(*(rng->obj()), false);
}
}
}
bool
exdsa_private_key_t::is_valid(rnp::RNG *rng) const
{
switch (curve_) {
case PGP_CURVE_ED25519: {
Botan::secure_vector<uint8_t> sv(key_.begin(), key_.end());
Botan::Ed25519_PrivateKey priv_key(sv);
return priv_key.check_key(*(rng->obj()), false);
}
case PGP_CURVE_ED448: {
Botan::Ed448_PrivateKey priv_key(key_);
return priv_key.check_key(*(rng->obj()), false);
}
default: {
auto priv_key = exdsa_privkey_from_bytes(rng, key_.data(), key_.size(), curve_);
return priv_key.check_key(*(rng->obj()), false);
}
}
}
#endif
bool
ecdh_kem_public_key_t::is_valid(rnp::RNG *rng) const
{
switch (curve_) {
case PGP_CURVE_25519: {
auto pub_key = x25519_pubkey_from_bytes(key_);
return pub_key.check_key(*(rng->obj()), false);
}
#if defined(ENABLE_CRYPTO_REFRESH)
case PGP_CURVE_448: {
auto pub_key = x448_pubkey_from_bytes(key_);
return pub_key.check_key(*(rng->obj()), false);
}
#endif
default: {
auto pub_key = ecdh_kem_pubkey_from_bytes(rng, key_, curve_);
return pub_key.check_key(*(rng->obj()), false);
}
}
}
bool
ecdh_kem_private_key_t::is_valid(rnp::RNG *rng) const
{
switch (curve_) {
case PGP_CURVE_25519: {
auto priv_key = x25519_privkey_from_bytes(key_.data(), key_.size());
return priv_key.check_key(*(rng->obj()), false);
}
#if defined(ENABLE_CRYPTO_REFRESH)
case PGP_CURVE_448: {
auto priv_key = x448_privkey_from_bytes(key_.data(), key_.size());
return priv_key.check_key(*(rng->obj()), false);
}
#endif
default: {
auto priv_key = ecdh_kem_privkey_from_bytes(rng, key_.data(), key_.size(), curve_);
return priv_key.check_key(*(rng->obj()), false);
}
}
}