ext-cryptopp/fhmqv.h
2016-12-03 05:05:56 -05:00

303 lines
12 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// fhmqv.h - written and placed in the public domain by Jeffrey Walton, Ray Clayton and Uri Blumenthal
// Shamelessly based upon Wei Dai's MQV source files
#ifndef CRYPTOPP_FHMQV_H
#define CRYPTOPP_FHMQV_H
//! \file fhmqv.h
//! \brief Classes for Fully Hashed Menezes-Qu-Vanstone key agreement in GF(p)
//! \since Crypto++ 5.6.4
#include "gfpcrypt.h"
#include "algebra.h"
#include "sha.h"
NAMESPACE_BEGIN(CryptoPP)
//! \brief Fully Hashed Menezes-Qu-Vanstone in GF(p)
//! \details This implementation follows Augustin P. Sarr and Philippe ElbazVincent, and JeanClaude Bajard's
//! <a href="http://eprint.iacr.org/2009/408">A Secure and Efficient Authenticated Diffie-Hellman Protocol</a>.
//! Note: this is FHMQV, Protocol 5, from page 11; and not FHMQV-C.
//! \sa MQV, HMQV, FHMQV, and AuthenticatedKeyAgreementDomain
//! \since Crypto++ 5.6.4
template <class GROUP_PARAMETERS, class COFACTOR_OPTION = typename GROUP_PARAMETERS::DefaultCofactorOption, class HASH = SHA512>
class FHMQV_Domain : public AuthenticatedKeyAgreementDomain
{
public:
typedef GROUP_PARAMETERS GroupParameters;
typedef typename GroupParameters::Element Element;
typedef FHMQV_Domain<GROUP_PARAMETERS, COFACTOR_OPTION, HASH> Domain;
virtual ~FHMQV_Domain() {}
FHMQV_Domain(bool clientRole = true): m_role(clientRole ? RoleClient : RoleServer) {}
FHMQV_Domain(const GroupParameters &params, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer), m_groupParameters(params) {}
FHMQV_Domain(BufferedTransformation &bt, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer)
{m_groupParameters.BERDecode(bt);}
template <class T1>
FHMQV_Domain(T1 v1, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer)
{m_groupParameters.Initialize(v1);}
template <class T1, class T2>
FHMQV_Domain(T1 v1, T2 v2, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer)
{m_groupParameters.Initialize(v1, v2);}
template <class T1, class T2, class T3>
FHMQV_Domain(T1 v1, T2 v2, T3 v3, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer)
{m_groupParameters.Initialize(v1, v2, v3);}
template <class T1, class T2, class T3, class T4>
FHMQV_Domain(T1 v1, T2 v2, T3 v3, T4 v4, bool clientRole = true)
: m_role(clientRole ? RoleClient : RoleServer)
{m_groupParameters.Initialize(v1, v2, v3, v4);}
public:
const GroupParameters & GetGroupParameters() const {return m_groupParameters;}
GroupParameters & AccessGroupParameters(){return m_groupParameters;}
CryptoParameters & AccessCryptoParameters(){return AccessAbstractGroupParameters();}
//! return length of agreed value produced
unsigned int AgreedValueLength() const {return GetAbstractGroupParameters().GetEncodedElementSize(false);}
//! return length of static private keys in this domain
unsigned int StaticPrivateKeyLength() const {return GetAbstractGroupParameters().GetSubgroupOrder().ByteCount();}
//! return length of static public keys in this domain
unsigned int StaticPublicKeyLength() const{return GetAbstractGroupParameters().GetEncodedElementSize(true);}
//! generate static private key
/*! \pre size of privateKey == PrivateStaticKeyLength() */
void GenerateStaticPrivateKey(RandomNumberGenerator &rng, byte *privateKey) const
{
Integer x(rng, Integer::One(), GetAbstractGroupParameters().GetMaxExponent());
x.Encode(privateKey, StaticPrivateKeyLength());
}
//! generate static public key
/*! \pre size of publicKey == PublicStaticKeyLength() */
void GenerateStaticPublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
{
CRYPTOPP_UNUSED(rng);
const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
Integer x(privateKey, StaticPrivateKeyLength());
Element y = params.ExponentiateBase(x);
params.EncodeElement(true, y, publicKey);
}
unsigned int EphemeralPrivateKeyLength() const {return StaticPrivateKeyLength() + StaticPublicKeyLength();}
unsigned int EphemeralPublicKeyLength() const{return StaticPublicKeyLength();}
//! return length of ephemeral private keys in this domain
void GenerateEphemeralPrivateKey(RandomNumberGenerator &rng, byte *privateKey) const
{
const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
Integer x(rng, Integer::One(), params.GetMaxExponent());
x.Encode(privateKey, StaticPrivateKeyLength());
Element y = params.ExponentiateBase(x);
params.EncodeElement(true, y, privateKey+StaticPrivateKeyLength());
}
//! return length of ephemeral public keys in this domain
void GenerateEphemeralPublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
{
CRYPTOPP_UNUSED(rng);
memcpy(publicKey, privateKey+StaticPrivateKeyLength(), EphemeralPublicKeyLength());
}
//! derive agreed value from your private keys and couterparty's public keys, return false in case of failure
/*! \note The ephemeral public key will always be validated.
If you have previously validated the static public key, use validateStaticOtherPublicKey=false to save time.
\pre size of agreedValue == AgreedValueLength()
\pre length of staticPrivateKey == StaticPrivateKeyLength()
\pre length of ephemeralPrivateKey == EphemeralPrivateKeyLength()
\pre length of staticOtherPublicKey == StaticPublicKeyLength()
\pre length of ephemeralOtherPublicKey == EphemeralPublicKeyLength()
*/
bool Agree(byte *agreedValue,
const byte *staticPrivateKey, const byte *ephemeralPrivateKey,
const byte *staticOtherPublicKey, const byte *ephemeralOtherPublicKey,
bool validateStaticOtherPublicKey=true) const
{
byte *XX = NULL, *YY = NULL, *AA = NULL, *BB = NULL;
size_t xxs = 0, yys = 0, aas = 0, bbs = 0;
// Depending on the role, this will hold either A's or B's static
// (long term) public key. AA or BB will then point into tt.
SecByteBlock tt(StaticPublicKeyLength());
try
{
const DL_GroupParameters<Element> &params = GetAbstractGroupParameters();
if(m_role == RoleServer)
{
Integer b(staticPrivateKey, StaticPrivateKeyLength());
Element B = params.ExponentiateBase(b);
params.EncodeElement(true, B, tt);
XX = const_cast<byte*>(ephemeralOtherPublicKey);
xxs = EphemeralPublicKeyLength();
YY = const_cast<byte*>(ephemeralPrivateKey) + StaticPrivateKeyLength();
yys = EphemeralPublicKeyLength();
AA = const_cast<byte*>(staticOtherPublicKey);
aas = StaticPublicKeyLength();
BB = tt.BytePtr();
bbs = tt.SizeInBytes();
}
else if(m_role == RoleClient)
{
Integer a(staticPrivateKey, StaticPrivateKeyLength());
Element A = params.ExponentiateBase(a);
params.EncodeElement(true, A, tt);
XX = const_cast<byte*>(ephemeralPrivateKey) + StaticPrivateKeyLength();
xxs = EphemeralPublicKeyLength();
YY = const_cast<byte*>(ephemeralOtherPublicKey);
yys = EphemeralPublicKeyLength();
AA = tt.BytePtr();
aas = tt.SizeInBytes();
BB = const_cast<byte*>(staticOtherPublicKey);
bbs = StaticPublicKeyLength();
}
else
{
CRYPTOPP_ASSERT(0);
return false;
}
// DecodeElement calls ValidateElement at level 1. Level 1 only calls
// VerifyPoint to ensure the element is in G*. If the other's PublicKey is
// requested to be validated, we manually call ValidateElement at level 3.
Element VV1 = params.DecodeElement(staticOtherPublicKey, false);
if(!params.ValidateElement(validateStaticOtherPublicKey ? 3 : 1, VV1, NULL))
return false;
// DecodeElement calls ValidateElement at level 1. Level 1 only calls
// VerifyPoint to ensure the element is in G*. Crank it up.
Element VV2 = params.DecodeElement(ephemeralOtherPublicKey, false);
if(!params.ValidateElement(3, VV2, NULL))
return false;
const Integer& q = params.GetSubgroupOrder();
const unsigned int len /*bytes*/ = (((q.BitCount()+1)/2 +7)/8);
Integer d, e;
SecByteBlock dd(len), ee(len);
Hash(NULL, XX, xxs, YY, yys, AA, aas, BB, bbs, dd.BytePtr(), dd.SizeInBytes());
d.Decode(dd.BytePtr(), dd.SizeInBytes());
Hash(NULL, YY, yys, XX, xxs, AA, aas, BB, bbs, ee.BytePtr(), ee.SizeInBytes());
e.Decode(ee.BytePtr(), ee.SizeInBytes());
Element sigma;
if(m_role == RoleServer)
{
Integer y(ephemeralPrivateKey, StaticPrivateKeyLength());
Integer b(staticPrivateKey, StaticPrivateKeyLength());
Integer s_B = (y + e * b) % q;
Element A = params.DecodeElement(AA, false);
Element X = params.DecodeElement(XX, false);
Element t1 = params.ExponentiateElement(A, d);
Element t2 = m_groupParameters.MultiplyElements(X, t1);
sigma = params.ExponentiateElement(t2, s_B);
}
else
{
Integer x(ephemeralPrivateKey, StaticPrivateKeyLength());
Integer a(staticPrivateKey, StaticPrivateKeyLength());
Integer s_A = (x + d * a) % q;
Element B = params.DecodeElement(BB, false);
Element Y = params.DecodeElement(YY, false);
Element t1 = params.ExponentiateElement(B, e);
Element t2 = m_groupParameters.MultiplyElements(Y, t1);
sigma = params.ExponentiateElement(t2, s_A);
}
Hash(&sigma, XX, xxs, YY, yys, AA, aas, BB, bbs, agreedValue, AgreedValueLength());
}
catch (DL_BadElement &)
{
return false;
}
return true;
}
protected:
inline void Hash(const Element* sigma,
const byte* e1, size_t e1len, const byte* e2, size_t e2len,
const byte* s1, size_t s1len, const byte* s2, size_t s2len,
byte* digest, size_t dlen) const
{
HASH hash;
size_t idx = 0, req = dlen;
size_t blk = STDMIN(dlen, (size_t)HASH::DIGESTSIZE);
if(sigma)
{
Integer x = GetAbstractGroupParameters().ConvertElementToInteger(*sigma);
SecByteBlock sbb(x.MinEncodedSize());
x.Encode(sbb.BytePtr(), sbb.SizeInBytes());
hash.Update(sbb.BytePtr(), sbb.SizeInBytes());
}
hash.Update(e1, e1len);
hash.Update(e2, e2len);
hash.Update(s1, s1len);
hash.Update(s2, s2len);
hash.TruncatedFinal(digest, blk);
req -= blk;
// All this to catch tail bytes for large curves and small hashes
while(req != 0)
{
hash.Update(&digest[idx], (size_t)HASH::DIGESTSIZE);
idx += (size_t)HASH::DIGESTSIZE;
blk = STDMIN(req, (size_t)HASH::DIGESTSIZE);
hash.TruncatedFinal(&digest[idx], blk);
req -= blk;
}
}
private:
// The paper uses Initiator and Recipient - make it classical.
enum KeyAgreementRole{ RoleServer = 1, RoleClient };
DL_GroupParameters<Element> & AccessAbstractGroupParameters() {return m_groupParameters;}
const DL_GroupParameters<Element> & GetAbstractGroupParameters() const{return m_groupParameters;}
GroupParameters m_groupParameters;
KeyAgreementRole m_role;
};
//! \brief Fully Hashed Menezes-Qu-Vanstone in GF(p)
//! \details This implementation follows Augustin P. Sarr and Philippe ElbazVincent, and JeanClaude Bajard's
//! <a href="http://eprint.iacr.org/2009/408">A Secure and Efficient Authenticated Diffie-Hellman Protocol</a>.
//! Note: this is FHMQV, Protocol 5, from page 11; and not FHMQV-C.
//! \sa FHMQV, MQV_Domain, HMQV_Domain, AuthenticatedKeyAgreementDomain
//! \since Crypto++ 5.6.4
typedef FHMQV_Domain<DL_GroupParameters_GFP_DefaultSafePrime> FHMQV;
NAMESPACE_END
#endif