307 lines
12 KiB
C++
307 lines
12 KiB
C++
/*! \file
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This file contains helper classes for implementing stream ciphers.
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All this infrastructure may look very complex compared to what's in Crypto++ 4.x,
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but stream ciphers implementations now support a lot of new functionality,
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including better performance (minimizing copying), resetting of keys and IVs, and methods to
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query which features are supported by a cipher.
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Here's an explanation of these classes. The word "policy" is used here to mean a class with a
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set of methods that must be implemented by individual stream cipher implementations.
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This is usually much simpler than the full stream cipher API, which is implemented by
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either AdditiveCipherTemplate or CFB_CipherTemplate using the policy. So for example, an
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implementation of SEAL only needs to implement the AdditiveCipherAbstractPolicy interface
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(since it's an additive cipher, i.e., it xors a keystream into the plaintext).
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See this line in seal.h:
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typedef SymmetricCipherFinal\<ConcretePolicyHolder\<SEAL_Policy\<B\>, AdditiveCipherTemplate\<\> \> \> Encryption;
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AdditiveCipherTemplate and CFB_CipherTemplate are designed so that they don't need
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to take a policy class as a template parameter (although this is allowed), so that
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their code is not duplicated for each new cipher. Instead they each
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get a reference to an abstract policy interface by calling AccessPolicy() on itself, so
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AccessPolicy() must be overriden to return the actual policy reference. This is done
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by the ConceretePolicyHolder class. Finally, SymmetricCipherFinal implements the constructors and
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other functions that must be implemented by the most derived class.
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*/
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#ifndef CRYPTOPP_STRCIPHR_H
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#define CRYPTOPP_STRCIPHR_H
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#include "seckey.h"
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#include "secblock.h"
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#include "argnames.h"
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NAMESPACE_BEGIN(CryptoPP)
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template <class POLICY_INTERFACE, class BASE = Empty>
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class CRYPTOPP_NO_VTABLE AbstractPolicyHolder : public BASE
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{
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public:
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typedef POLICY_INTERFACE PolicyInterface;
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virtual ~AbstractPolicyHolder() {}
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protected:
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virtual const POLICY_INTERFACE & GetPolicy() const =0;
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virtual POLICY_INTERFACE & AccessPolicy() =0;
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};
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template <class POLICY, class BASE, class POLICY_INTERFACE = CPP_TYPENAME BASE::PolicyInterface>
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class ConcretePolicyHolder : public BASE, protected POLICY
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{
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protected:
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const POLICY_INTERFACE & GetPolicy() const {return *this;}
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POLICY_INTERFACE & AccessPolicy() {return *this;}
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};
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enum KeystreamOperationFlags {OUTPUT_ALIGNED=1, INPUT_ALIGNED=2, INPUT_NULL = 4};
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enum KeystreamOperation {
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WRITE_KEYSTREAM = INPUT_NULL,
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WRITE_KEYSTREAM_ALIGNED = INPUT_NULL | OUTPUT_ALIGNED,
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XOR_KEYSTREAM = 0,
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XOR_KEYSTREAM_INPUT_ALIGNED = INPUT_ALIGNED,
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XOR_KEYSTREAM_OUTPUT_ALIGNED= OUTPUT_ALIGNED,
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XOR_KEYSTREAM_BOTH_ALIGNED = OUTPUT_ALIGNED | INPUT_ALIGNED};
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struct CRYPTOPP_DLL CRYPTOPP_NO_VTABLE AdditiveCipherAbstractPolicy
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{
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virtual ~AdditiveCipherAbstractPolicy() {}
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virtual unsigned int GetAlignment() const {return 1;}
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virtual unsigned int GetBytesPerIteration() const =0;
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virtual unsigned int GetOptimalBlockSize() const {return GetBytesPerIteration();}
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virtual unsigned int GetIterationsToBuffer() const =0;
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virtual void WriteKeystream(byte *keystream, size_t iterationCount)
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{OperateKeystream(KeystreamOperation(INPUT_NULL | (KeystreamOperationFlags)IsAlignedOn(keystream, GetAlignment())), keystream, NULL, iterationCount);}
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virtual bool CanOperateKeystream() const {return false;}
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virtual void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount) {assert(false);}
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virtual void CipherSetKey(const NameValuePairs ¶ms, const byte *key, size_t length) =0;
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virtual void CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length) {throw NotImplemented("SimpleKeyingInterface: this object doesn't support resynchronization");}
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virtual bool CipherIsRandomAccess() const =0;
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virtual void SeekToIteration(lword iterationCount) {assert(!CipherIsRandomAccess()); throw NotImplemented("StreamTransformation: this object doesn't support random access");}
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};
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template <typename WT, unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>
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struct CRYPTOPP_NO_VTABLE AdditiveCipherConcretePolicy : public BASE
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{
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typedef WT WordType;
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CRYPTOPP_CONSTANT(BYTES_PER_ITERATION = sizeof(WordType) * W)
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#if !(CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X64)
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unsigned int GetAlignment() const {return GetAlignmentOf<WordType>();}
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#endif
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unsigned int GetBytesPerIteration() const {return BYTES_PER_ITERATION;}
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unsigned int GetIterationsToBuffer() const {return X;}
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bool CanOperateKeystream() const {return true;}
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virtual void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount) =0;
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};
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// use these to implement OperateKeystream
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#define CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, b, i, a) \
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PutWord(bool(x & OUTPUT_ALIGNED), b, output+i*sizeof(WordType), (x & INPUT_NULL) ? a : a ^ GetWord<WordType>(bool(x & INPUT_ALIGNED), b, input+i*sizeof(WordType)));
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#define CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, i, a) {\
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__m128i t = (x & INPUT_NULL) ? a : _mm_xor_si128(a, (x & INPUT_ALIGNED) ? _mm_load_si128((__m128i *)input+i) : _mm_loadu_si128((__m128i *)input+i));\
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if (x & OUTPUT_ALIGNED) _mm_store_si128((__m128i *)output+i, t);\
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else _mm_storeu_si128((__m128i *)output+i, t);}
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#define CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(x, y) \
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switch (operation) \
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{ \
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case WRITE_KEYSTREAM: \
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x(WRITE_KEYSTREAM) \
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break; \
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case XOR_KEYSTREAM: \
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x(XOR_KEYSTREAM) \
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input += y; \
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break; \
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case XOR_KEYSTREAM_INPUT_ALIGNED: \
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x(XOR_KEYSTREAM_INPUT_ALIGNED) \
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input += y; \
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break; \
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case XOR_KEYSTREAM_OUTPUT_ALIGNED: \
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x(XOR_KEYSTREAM_OUTPUT_ALIGNED) \
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input += y; \
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break; \
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case WRITE_KEYSTREAM_ALIGNED: \
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x(WRITE_KEYSTREAM_ALIGNED) \
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break; \
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case XOR_KEYSTREAM_BOTH_ALIGNED: \
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x(XOR_KEYSTREAM_BOTH_ALIGNED) \
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input += y; \
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break; \
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} \
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output += y;
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template <class BASE = AbstractPolicyHolder<AdditiveCipherAbstractPolicy, SymmetricCipher> >
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class CRYPTOPP_NO_VTABLE AdditiveCipherTemplate : public BASE, public RandomNumberGenerator
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{
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public:
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void GenerateBlock(byte *output, size_t size);
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void ProcessData(byte *outString, const byte *inString, size_t length);
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void Resynchronize(const byte *iv, int length=-1);
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unsigned int OptimalBlockSize() const {return this->GetPolicy().GetOptimalBlockSize();}
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unsigned int GetOptimalNextBlockSize() const {return (unsigned int)this->m_leftOver;}
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unsigned int OptimalDataAlignment() const {return this->GetPolicy().GetAlignment();}
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bool IsSelfInverting() const {return true;}
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bool IsForwardTransformation() const {return true;}
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bool IsRandomAccess() const {return this->GetPolicy().CipherIsRandomAccess();}
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void Seek(lword position);
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typedef typename BASE::PolicyInterface PolicyInterface;
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protected:
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void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms);
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unsigned int GetBufferByteSize(const PolicyInterface &policy) const {return policy.GetBytesPerIteration() * policy.GetIterationsToBuffer();}
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inline byte * KeystreamBufferBegin() {return this->m_buffer.data();}
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inline byte * KeystreamBufferEnd() {return (this->m_buffer.data() + this->m_buffer.size());}
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SecByteBlock m_buffer;
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size_t m_leftOver;
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};
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class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CFB_CipherAbstractPolicy
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{
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public:
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virtual ~CFB_CipherAbstractPolicy() {}
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virtual unsigned int GetAlignment() const =0;
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virtual unsigned int GetBytesPerIteration() const =0;
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virtual byte * GetRegisterBegin() =0;
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virtual void TransformRegister() =0;
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virtual bool CanIterate() const {return false;}
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virtual void Iterate(byte *output, const byte *input, CipherDir dir, size_t iterationCount) {assert(false); throw 0;}
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virtual void CipherSetKey(const NameValuePairs ¶ms, const byte *key, size_t length) =0;
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virtual void CipherResynchronize(const byte *iv, size_t length) {throw NotImplemented("SimpleKeyingInterface: this object doesn't support resynchronization");}
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};
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template <typename WT, unsigned int W, class BASE = CFB_CipherAbstractPolicy>
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struct CRYPTOPP_NO_VTABLE CFB_CipherConcretePolicy : public BASE
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{
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typedef WT WordType;
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unsigned int GetAlignment() const {return sizeof(WordType);}
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unsigned int GetBytesPerIteration() const {return sizeof(WordType) * W;}
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bool CanIterate() const {return true;}
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void TransformRegister() {this->Iterate(NULL, NULL, ENCRYPTION, 1);}
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template <class B>
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struct RegisterOutput
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{
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RegisterOutput(byte *output, const byte *input, CipherDir dir)
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: m_output(output), m_input(input), m_dir(dir) {}
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inline RegisterOutput& operator()(WordType ®isterWord)
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{
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assert(IsAligned<WordType>(m_output));
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assert(IsAligned<WordType>(m_input));
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if (!NativeByteOrderIs(B::ToEnum()))
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registerWord = ByteReverse(registerWord);
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if (m_dir == ENCRYPTION)
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{
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if (m_input == NULL)
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assert(m_output == NULL);
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else
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{
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WordType ct = *(const WordType *)m_input ^ registerWord;
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registerWord = ct;
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*(WordType*)m_output = ct;
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m_input += sizeof(WordType);
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m_output += sizeof(WordType);
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}
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}
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else
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{
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WordType ct = *(const WordType *)m_input;
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*(WordType*)m_output = registerWord ^ ct;
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registerWord = ct;
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m_input += sizeof(WordType);
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m_output += sizeof(WordType);
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}
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// registerWord is left unreversed so it can be xor-ed with further input
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return *this;
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}
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byte *m_output;
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const byte *m_input;
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CipherDir m_dir;
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};
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};
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template <class BASE>
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class CRYPTOPP_NO_VTABLE CFB_CipherTemplate : public BASE
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{
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public:
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void ProcessData(byte *outString, const byte *inString, size_t length);
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void Resynchronize(const byte *iv, int length=-1);
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unsigned int OptimalBlockSize() const {return this->GetPolicy().GetBytesPerIteration();}
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unsigned int GetOptimalNextBlockSize() const {return (unsigned int)m_leftOver;}
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unsigned int OptimalDataAlignment() const {return this->GetPolicy().GetAlignment();}
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bool IsRandomAccess() const {return false;}
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bool IsSelfInverting() const {return false;}
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typedef typename BASE::PolicyInterface PolicyInterface;
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protected:
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virtual void CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length) =0;
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void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms);
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size_t m_leftOver;
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};
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template <class BASE = AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >
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class CRYPTOPP_NO_VTABLE CFB_EncryptionTemplate : public CFB_CipherTemplate<BASE>
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{
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bool IsForwardTransformation() const {return true;}
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void CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length);
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};
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template <class BASE = AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >
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class CRYPTOPP_NO_VTABLE CFB_DecryptionTemplate : public CFB_CipherTemplate<BASE>
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{
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bool IsForwardTransformation() const {return false;}
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void CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length);
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};
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template <class BASE>
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class CFB_RequireFullDataBlocks : public BASE
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{
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public:
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unsigned int MandatoryBlockSize() const {return this->OptimalBlockSize();}
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};
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//! _
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template <class BASE, class INFO = BASE>
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class SymmetricCipherFinal : public AlgorithmImpl<SimpleKeyingInterfaceImpl<BASE, INFO>, INFO>
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{
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public:
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SymmetricCipherFinal() {}
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SymmetricCipherFinal(const byte *key)
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{this->SetKey(key, this->DEFAULT_KEYLENGTH);}
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SymmetricCipherFinal(const byte *key, size_t length)
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{this->SetKey(key, length);}
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SymmetricCipherFinal(const byte *key, size_t length, const byte *iv)
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{this->SetKeyWithIV(key, length, iv);}
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Clonable * Clone() const {return static_cast<SymmetricCipher *>(new SymmetricCipherFinal<BASE, INFO>(*this));}
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};
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NAMESPACE_END
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#ifdef CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
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#include "strciphr.cpp"
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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CRYPTOPP_DLL_TEMPLATE_CLASS AbstractPolicyHolder<AdditiveCipherAbstractPolicy, SymmetricCipher>;
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CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, SymmetricCipher> >;
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CRYPTOPP_DLL_TEMPLATE_CLASS CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >;
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CRYPTOPP_DLL_TEMPLATE_CLASS CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >;
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CRYPTOPP_DLL_TEMPLATE_CLASS CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >;
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NAMESPACE_END
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#endif
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