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server/game/src/cipher.cpp

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#include "stdafx.h"
#include "cipher.h"
#ifdef _IMPROVED_PACKET_ENCRYPTION_
#include <cryptopp/modes.h>
#include <cryptopp/nbtheory.h>
#include <cryptopp/osrng.h>
// Diffie-Hellman key agreement
#include <cryptopp/dh.h>
#include <cryptopp/dh2.h>
// AES winner and candidates
//#include <cryptopp/aes.h>
#include <cryptopp/cast.h>
#include <cryptopp/rc6.h>
#include <cryptopp/mars.h>
#include <cryptopp/serpent.h>
#include <cryptopp/twofish.h>
// Other block ciphers
#include <cryptopp/blowfish.h>
#include <cryptopp/camellia.h>
#include <cryptopp/des.h>
#include <cryptopp/idea.h>
#include <cryptopp/rc5.h>
#include <cryptopp/seed.h>
#include <cryptopp/shacal2.h>
#include <cryptopp/skipjack.h>
#include <cryptopp/tea.h>
using namespace CryptoPP;
// Block cipher algorithm selector abstract base class.
struct BlockCipherAlgorithm {
enum {
kDefault, // to give more chances to default algorithm
// AES winner and candidates
// kAES, // Rijndael
kRC6,
kMARS,
kTwofish,
kSerpent,
kCAST256,
// Other block ciphers
kIDEA,
k3DES, // DES-EDE2
kCamellia,
kSEED,
kRC5,
kBlowfish,
kTEA,
// kSKIPJACK,
kSHACAL2,
// End sentinel
kMaxAlgorithms
};
BlockCipherAlgorithm() {}
virtual ~BlockCipherAlgorithm() {}
static BlockCipherAlgorithm* Pick(int hint);
virtual int GetBlockSize() const = 0;
virtual int GetDefaultKeyLength() const = 0;
virtual int GetIVLength() const = 0;
virtual SymmetricCipher* CreateEncoder(const byte* key, size_t keylen,
const byte* iv) const = 0;
virtual SymmetricCipher* CreateDecoder(const byte* key, size_t keylen,
const byte* iv) const = 0;
};
// Block cipher (with CTR mode) algorithm selector template class.
template<class T>
struct BlockCipherDetail : public BlockCipherAlgorithm {
BlockCipherDetail() {}
virtual ~BlockCipherDetail() {}
virtual int GetBlockSize() const { return T::BLOCKSIZE; }
virtual int GetDefaultKeyLength() const { return T::DEFAULT_KEYLENGTH; }
virtual int GetIVLength() const { return T::IV_LENGTH; }
virtual SymmetricCipher* CreateEncoder(const byte* key, size_t keylen,
const byte* iv) const {
return new typename CTR_Mode<T>::Encryption(key, keylen, iv);
}
virtual SymmetricCipher* CreateDecoder(const byte* key, size_t keylen,
const byte* iv) const {
return new typename CTR_Mode<T>::Decryption(key, keylen, iv);
}
};
// Key agreement scheme abstract class.
class KeyAgreement {
public:
KeyAgreement() {}
virtual ~KeyAgreement() {}
virtual size_t Prepare(void* buffer, size_t* length) = 0;
virtual bool Agree(size_t agreed_length, const void* buffer, size_t length) = 0;
const SecByteBlock& shared() const { return shared_; }
protected:
SecByteBlock shared_;
};
// Crypto++ Unified Diffie-Hellman key agreement scheme implementation.
class DH2KeyAgreement : public KeyAgreement {
public:
DH2KeyAgreement();
virtual ~DH2KeyAgreement();
virtual size_t Prepare(void* buffer, size_t* length);
virtual bool Agree(size_t agreed_length, const void* buffer, size_t length);
private:
DH dh_;
DH2 dh2_;
SecByteBlock spriv_key_;
SecByteBlock epriv_key_;
};
Cipher::Cipher()
: activated_(false), encoder_(NULL), decoder_(NULL), key_agreement_(NULL) {
}
Cipher::~Cipher() {
if (activated_) {
CleanUp();
}
}
void Cipher::CleanUp() {
if (encoder_ != NULL) {
delete encoder_;
encoder_ = NULL;
}
if (decoder_ != NULL) {
delete decoder_;
decoder_ = NULL;
}
if (key_agreement_ != NULL) {
delete key_agreement_;
key_agreement_ = NULL;
}
activated_ = false;
}
size_t Cipher::Prepare(void* buffer, size_t* length) {
assert(key_agreement_ == NULL);
key_agreement_ = new DH2KeyAgreement();
assert(key_agreement_ != NULL);
size_t agreed_length = key_agreement_->Prepare(buffer, length);
if (agreed_length == 0) {
delete key_agreement_;
key_agreement_ = NULL;
}
return agreed_length;
}
bool Cipher::Activate(bool polarity, size_t agreed_length,
const void* buffer, size_t length) {
assert(activated_ == false);
assert(key_agreement_ != NULL);
if (activated_ != false)
return false;
if (key_agreement_->Agree(agreed_length, buffer, length)) {
activated_ = SetUp(polarity);
}
delete key_agreement_;
key_agreement_ = NULL;
return activated_;
}
bool Cipher::SetUp(bool polarity) {
assert(key_agreement_ != NULL);
const SecByteBlock& shared = key_agreement_->shared();
// Pick a block cipher algorithm
if (shared.size() < 2) {
return false;
}
int hint_0 = shared.BytePtr()[*(shared.BytePtr()) % shared.size()];
int hint_1 = shared.BytePtr()[*(shared.BytePtr() + 1) % shared.size()];
BlockCipherAlgorithm* detail_0 = BlockCipherAlgorithm::Pick(hint_0);
BlockCipherAlgorithm* detail_1 = BlockCipherAlgorithm::Pick(hint_1);
assert(detail_0 != NULL);
assert(detail_1 != NULL);
std::unique_ptr<BlockCipherAlgorithm> algorithm_0(detail_0);
std::unique_ptr<BlockCipherAlgorithm> algorithm_1(detail_1);
const size_t key_length_0 = algorithm_0->GetDefaultKeyLength();
const size_t iv_length_0 = algorithm_0->GetBlockSize();
if (shared.size() < key_length_0 || shared.size() < iv_length_0) {
return false;
}
const size_t key_length_1 = algorithm_1->GetDefaultKeyLength();
const size_t iv_length_1 = algorithm_1->GetBlockSize();
if (shared.size() < key_length_1 || shared.size() < iv_length_1) {
return false;
}
// Pick encryption keys and initial vectors
SecByteBlock key_0(key_length_0), iv_0(iv_length_0);
SecByteBlock key_1(key_length_1), iv_1(iv_length_1);
size_t offset;
key_0.Assign(shared, key_length_0);
offset = key_length_0;
#ifdef __GNUC__
offset = std::min(key_length_0, shared.size() - key_length_1);
#else
offset = min(key_length_0, shared.size() - key_length_1);
#endif
key_1.Assign(shared.BytePtr() + offset, key_length_1);
offset = shared.size() - iv_length_0;
iv_0.Assign(shared.BytePtr() + offset, iv_length_0);
offset = (offset < iv_length_1 ? 0 : offset - iv_length_1);
iv_1.Assign(shared.BytePtr() + offset, iv_length_1);
// Create encryption/decryption objects
if (polarity) {
encoder_ = algorithm_1->CreateEncoder(key_1, key_1.size(), iv_1);
decoder_ = algorithm_0->CreateDecoder(key_0, key_0.size(), iv_0);
} else {
encoder_ = algorithm_0->CreateEncoder(key_0, key_0.size(), iv_0);
decoder_ = algorithm_1->CreateDecoder(key_1, key_1.size(), iv_1);
}
assert(encoder_ != NULL);
assert(decoder_ != NULL);
return true;
}
BlockCipherAlgorithm* BlockCipherAlgorithm::Pick(int hint) {
BlockCipherAlgorithm* detail;
int selector = hint % kMaxAlgorithms;
switch (selector) {
// case kAES:
// detail = new BlockCipherDetail<AES>();
break;
case kRC6:
detail = new BlockCipherDetail<RC6>();
break;
case kMARS:
detail = new BlockCipherDetail<MARS>();
break;
case kTwofish:
detail = new BlockCipherDetail<Twofish>();
break;
case kSerpent:
detail = new BlockCipherDetail<Serpent>();
break;
case kCAST256:
detail = new BlockCipherDetail<CAST256>();
break;
case kIDEA:
detail = new BlockCipherDetail<IDEA>();
break;
case k3DES:
detail = new BlockCipherDetail<DES_EDE2>();
break;
case kCamellia:
detail = new BlockCipherDetail<Camellia>();
break;
case kSEED:
detail = new BlockCipherDetail<SEED>();
break;
case kRC5:
detail = new BlockCipherDetail<RC5>();
break;
case kBlowfish:
detail = new BlockCipherDetail<Blowfish>();
break;
case kTEA:
detail = new BlockCipherDetail<TEA>();
break;
// case kSKIPJACK:
// detail = new BlockCipherDetail<SKIPJACK>();
// break;
case kSHACAL2:
detail = new BlockCipherDetail<SHACAL2>();
break;
case kDefault:
default:
detail = new BlockCipherDetail<Twofish>(); // default algorithm
break;
}
return detail;
}
DH2KeyAgreement::DH2KeyAgreement() : dh_(), dh2_(dh_) {
}
DH2KeyAgreement::~DH2KeyAgreement() {
}
size_t DH2KeyAgreement::Prepare(void* buffer, size_t* length) {
// RFC 5114, 1024-bit MODP Group with 160-bit Prime Order Subgroup
// http://tools.ietf.org/html/rfc5114#section-2.1
Integer p("0xB10B8F96A080E01DDE92DE5EAE5D54EC52C99FBCFB06A3C6"
"9A6A9DCA52D23B616073E28675A23D189838EF1E2EE652C0"
"13ECB4AEA906112324975C3CD49B83BFACCBDD7D90C4BD70"
"98488E9C219A73724EFFD6FAE5644738FAA31A4FF55BCCC0"
"A151AF5F0DC8B4BD45BF37DF365C1A65E68CFDA76D4DA708"
"DF1FB2BC2E4A4371");
Integer g("0xA4D1CBD5C3FD34126765A442EFB99905F8104DD258AC507F"
"D6406CFF14266D31266FEA1E5C41564B777E690F5504F213"
"160217B4B01B886A5E91547F9E2749F4D7FBD7D3B9A92EE1"
"909D0D2263F80A76A6A24C087A091F531DBF0A0169B6A28A"
"D662A4D18E73AFA32D779D5918D08BC8858F4DCEF97C2A24"
"855E6EEB22B3B2E5");
Integer q("0xF518AA8781A8DF278ABA4E7D64B7CB9D49462353");
// Schnorr Group primes are of the form p = rq + 1, p and q prime. They
// provide a subgroup order. In the case of 1024-bit MODP Group, the
// security level is 80 bits (based on the 160-bit prime order subgroup).
// For a compare/contrast of using the maximum security level, see
// dh-unified.zip. Also see http://www.cryptopp.com/wiki/Diffie-Hellman
// and http://www.cryptopp.com/wiki/Security_level .
AutoSeededRandomPool rnd;
dh_.AccessGroupParameters().Initialize(p, q, g);
if(!dh_.GetGroupParameters().ValidateGroup(rnd, 3)) {
// Failed to validate prime and generator
return 0;
}
p = dh_.GetGroupParameters().GetModulus();
q = dh_.GetGroupParameters().GetSubgroupOrder();
g = dh_.GetGroupParameters().GetGenerator();
// http://groups.google.com/group/sci.crypt/browse_thread/thread/7dc7eeb04a09f0ce
Integer v = ModularExponentiation(g, q, p);
if(v != Integer::One()) {
// Failed to verify order of the subgroup
return 0;
}
//////////////////////////////////////////////////////////////
spriv_key_.New(dh2_.StaticPrivateKeyLength());
epriv_key_.New(dh2_.EphemeralPrivateKeyLength());
SecByteBlock spub_key(dh2_.StaticPublicKeyLength());
SecByteBlock epub_key(dh2_.EphemeralPublicKeyLength());
dh2_.GenerateStaticKeyPair(rnd, spriv_key_, spub_key);
dh2_.GenerateEphemeralKeyPair(rnd, epriv_key_, epub_key);
// Prepare key agreement data
const size_t spub_key_length = spub_key.size();
const size_t epub_key_length = epub_key.size();
const size_t data_length = spub_key_length + epub_key_length;
if (*length < data_length) {
// Not enough data buffer length
return 0;
}
*length = data_length;
byte* buf = (byte*)buffer;
memcpy(buf, spub_key.BytePtr(), spub_key_length);
memcpy(buf + spub_key_length, epub_key.BytePtr(), epub_key_length);
return dh2_.AgreedValueLength();
}
bool DH2KeyAgreement::Agree(size_t agreed_length, const void* buffer, size_t length) {
if (agreed_length != dh2_.AgreedValueLength()) {
// Shared secret size mismatch
return false;
}
const size_t spub_key_length = dh2_.StaticPublicKeyLength();
const size_t epub_key_length = dh2_.EphemeralPublicKeyLength();
if (length != (spub_key_length + epub_key_length)) {
// Wrong data length
return false;
}
shared_.New(dh2_.AgreedValueLength());
const byte* buf = (const byte*)buffer;
if (!dh2_.Agree(shared_, spriv_key_, epriv_key_, buf, buf + spub_key_length)) {
// Failed to reach shared secret
return false;
}
return true;
}
#endif // _IMPROVED_PACKET_ENCRYPTION_
// EOF cipher.cpp
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