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/*
* Ed25519
* (C) 2017 Ribose Inc
*
* Based on the public domain code from SUPERCOP ref10 by
* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/ed25519.h>
#include <botan/internal/pk_ops_impl.h>
#include <botan/hash.h>
#include <botan/ber_dec.h>
#include <botan/der_enc.h>
#include <botan/rng.h>
namespace Botan {
AlgorithmIdentifier Ed25519_PublicKey::algorithm_identifier() const
{
return AlgorithmIdentifier(get_oid(), AlgorithmIdentifier::USE_EMPTY_PARAM);
}
bool Ed25519_PublicKey::check_key(RandomNumberGenerator&, bool) const
{
return true; // no tests possible?
// TODO could check cofactor
}
Ed25519_PublicKey::Ed25519_PublicKey(const uint8_t pub_key[], size_t pub_len)
{
if(pub_len != 32)
throw Decoding_Error("Invalid length for Ed25519 key");
m_public.assign(pub_key, pub_key + pub_len);
}
Ed25519_PublicKey::Ed25519_PublicKey(const AlgorithmIdentifier&,
const std::vector<uint8_t>& key_bits)
{
m_public = key_bits;
if(m_public.size() != 32)
throw Decoding_Error("Invalid size for Ed25519 public key");
}
std::vector<uint8_t> Ed25519_PublicKey::public_key_bits() const
{
return m_public;
}
Ed25519_PrivateKey::Ed25519_PrivateKey(const secure_vector<uint8_t>& secret_key)
{
if(secret_key.size() == 64)
{
m_private = secret_key;
m_public.assign(m_private.begin() + 32, m_private.end());
}
else if(secret_key.size() == 32)
{
m_public.resize(32);
m_private.resize(64);
ed25519_gen_keypair(m_public.data(), m_private.data(), secret_key.data());
}
else
throw Decoding_Error("Invalid size for Ed25519 private key");
}
Ed25519_PrivateKey::Ed25519_PrivateKey(RandomNumberGenerator& rng)
{
const secure_vector<uint8_t> seed = rng.random_vec(32);
m_public.resize(32);
m_private.resize(64);
ed25519_gen_keypair(m_public.data(), m_private.data(), seed.data());
}
Ed25519_PrivateKey::Ed25519_PrivateKey(const AlgorithmIdentifier&,
const secure_vector<uint8_t>& key_bits)
{
secure_vector<uint8_t> bits;
BER_Decoder(key_bits).decode(bits, OCTET_STRING).discard_remaining();
if(bits.size() != 32)
throw Decoding_Error("Invalid size for Ed25519 private key");
m_public.resize(32);
m_private.resize(64);
ed25519_gen_keypair(m_public.data(), m_private.data(), bits.data());
}
secure_vector<uint8_t> Ed25519_PrivateKey::private_key_bits() const
{
secure_vector<uint8_t> bits(&m_private[0], &m_private[32]);
return DER_Encoder().encode(bits, OCTET_STRING).get_contents();
}
bool Ed25519_PrivateKey::check_key(RandomNumberGenerator&, bool) const
{
return true; // ???
}
namespace {
/**
* Ed25519 verifying operation
*/
class Ed25519_Pure_Verify_Operation final : public PK_Ops::Verification
{
public:
Ed25519_Pure_Verify_Operation(const Ed25519_PublicKey& key) : m_key(key)
{
}
void update(const uint8_t msg[], size_t msg_len) override
{
m_msg.insert(m_msg.end(), msg, msg + msg_len);
}
bool is_valid_signature(const uint8_t sig[], size_t sig_len) override
{
if(sig_len != 64)
return false;
const std::vector<uint8_t>& pub_key = m_key.get_public_key();
BOTAN_ASSERT_EQUAL(pub_key.size(), 32, "Expected size");
const bool ok = ed25519_verify(m_msg.data(), m_msg.size(), sig, pub_key.data(), nullptr, 0);
m_msg.clear();
return ok;
}
private:
std::vector<uint8_t> m_msg;
const Ed25519_PublicKey& m_key;
};
/**
* Ed25519 verifying operation with pre-hash
*/
class Ed25519_Hashed_Verify_Operation final : public PK_Ops::Verification
{
public:
Ed25519_Hashed_Verify_Operation(const Ed25519_PublicKey& key, const std::string& hash, bool rfc8032) :
m_key(key)
{
m_hash = HashFunction::create_or_throw(hash);
if(rfc8032)
{
m_domain_sep = {
0x53, 0x69, 0x67, 0x45, 0x64, 0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x6E, 0x6F, 0x20, 0x45, 0x64,
0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x63, 0x6F, 0x6C, 0x6C, 0x69, 0x73, 0x69, 0x6F, 0x6E, 0x73,
0x01, 0x00 };
}
}
void update(const uint8_t msg[], size_t msg_len) override
{
m_hash->update(msg, msg_len);
}
bool is_valid_signature(const uint8_t sig[], size_t sig_len) override
{
if(sig_len != 64)
return false;
std::vector<uint8_t> msg_hash(m_hash->output_length());
m_hash->final(msg_hash.data());
const std::vector<uint8_t>& pub_key = m_key.get_public_key();
BOTAN_ASSERT_EQUAL(pub_key.size(), 32, "Expected size");
return ed25519_verify(msg_hash.data(), msg_hash.size(), sig, pub_key.data(), m_domain_sep.data(), m_domain_sep.size());
}
private:
std::unique_ptr<HashFunction> m_hash;
const Ed25519_PublicKey& m_key;
std::vector<uint8_t> m_domain_sep;
};
/**
* Ed25519 signing operation ('pure' - signs message directly)
*/
class Ed25519_Pure_Sign_Operation final : public PK_Ops::Signature
{
public:
Ed25519_Pure_Sign_Operation(const Ed25519_PrivateKey& key) : m_key(key)
{
}
void update(const uint8_t msg[], size_t msg_len) override
{
m_msg.insert(m_msg.end(), msg, msg + msg_len);
}
secure_vector<uint8_t> sign(RandomNumberGenerator&) override
{
secure_vector<uint8_t> sig(64);
ed25519_sign(sig.data(), m_msg.data(), m_msg.size(), m_key.get_private_key().data(), nullptr, 0);
m_msg.clear();
return sig;
}
size_t signature_length() const override { return 64; }
private:
std::vector<uint8_t> m_msg;
const Ed25519_PrivateKey& m_key;
};
/**
* Ed25519 signing operation with pre-hash
*/
class Ed25519_Hashed_Sign_Operation final : public PK_Ops::Signature
{
public:
Ed25519_Hashed_Sign_Operation(const Ed25519_PrivateKey& key, const std::string& hash, bool rfc8032) :
m_key(key)
{
m_hash = HashFunction::create_or_throw(hash);
if(rfc8032)
{
m_domain_sep = std::vector<uint8_t>{
0x53, 0x69, 0x67, 0x45, 0x64, 0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x6E, 0x6F, 0x20, 0x45, 0x64,
0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x63, 0x6F, 0x6C, 0x6C, 0x69, 0x73, 0x69, 0x6F, 0x6E, 0x73,
0x01, 0x00 };
}
}
size_t signature_length() const override { return 64; }
void update(const uint8_t msg[], size_t msg_len) override
{
m_hash->update(msg, msg_len);
}
secure_vector<uint8_t> sign(RandomNumberGenerator&) override
{
secure_vector<uint8_t> sig(64);
std::vector<uint8_t> msg_hash(m_hash->output_length());
m_hash->final(msg_hash.data());
ed25519_sign(sig.data(),
msg_hash.data(), msg_hash.size(),
m_key.get_private_key().data(),
m_domain_sep.data(), m_domain_sep.size());
return sig;
}
private:
std::unique_ptr<HashFunction> m_hash;
const Ed25519_PrivateKey& m_key;
std::vector<uint8_t> m_domain_sep;
};
}
std::unique_ptr<PK_Ops::Verification>
Ed25519_PublicKey::create_verification_op(const std::string& params,
const std::string& provider) const
{
if(provider == "base" || provider.empty())
{
if(params == "" || params == "Identity" || params == "Pure")
return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Pure_Verify_Operation(*this));
else if(params == "Ed25519ph")
return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Hashed_Verify_Operation(*this, "SHA-512", true));
else
return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Hashed_Verify_Operation(*this, params, false));
}
throw Provider_Not_Found(algo_name(), provider);
}
std::unique_ptr<PK_Ops::Signature>
Ed25519_PrivateKey::create_signature_op(RandomNumberGenerator&,
const std::string& params,
const std::string& provider) const
{
if(provider == "base" || provider.empty())
{
if(params == "" || params == "Identity" || params == "Pure")
return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Pure_Sign_Operation(*this));
else if(params == "Ed25519ph")
return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Hashed_Sign_Operation(*this, "SHA-512", true));
else
return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Hashed_Sign_Operation(*this, params, false));
}
throw Provider_Not_Found(algo_name(), provider);
}
}
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