Crypto++  5.6.4
Free C++ class library of cryptographic schemes
Classes | Macros | Enumerations
strciphr.h File Reference

Classes for implementing stream ciphers. More...

Go to the source code of this file.

Classes

class  AbstractPolicyHolder< POLICY_INTERFACE, BASE >
 Access a stream cipher policy object. More...
 
class  ConcretePolicyHolder< POLICY, BASE, POLICY_INTERFACE >
 Stream cipher policy object. More...
 
class  AdditiveCipherAbstractPolicy
 Policy object for additive stream ciphers. More...
 
class  AdditiveCipherConcretePolicy< WT, W, X, BASE >
 Base class for additive stream ciphers. More...
 
class  AdditiveCipherTemplate< BASE >
 Base class for additive stream ciphers with SymmetricCipher interface. More...
 
class  CFB_CipherAbstractPolicy
 Policy object for feeback based stream ciphers. More...
 
class  CFB_CipherConcretePolicy< WT, W, BASE >
 Base class for feedback based stream ciphers. More...
 
struct  CFB_CipherConcretePolicy< WT, W, BASE >::RegisterOutput< B >
 
class  CFB_CipherTemplate< BASE >
 Base class for feedback based stream ciphers with SymmetricCipher interface. More...
 
class  CFB_EncryptionTemplate< BASE >
 Base class for feedback based stream ciphers in the forward direction with SymmetricCipher interface. More...
 
class  CFB_DecryptionTemplate< BASE >
 Base class for feedback based stream ciphers in the reverse direction with SymmetricCipher interface. More...
 
class  CFB_RequireFullDataBlocks< BASE >
 Base class for feedback based stream ciphers with a mandatory block size. More...
 
class  SymmetricCipherFinal< BASE, INFO >
 SymmetricCipher implementation. More...
 

Macros

#define CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, b, i, a)   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)));
 Helper macro to implement OperateKeystream.
 
#define CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, i, a)
 Helper macro to implement OperateKeystream. More...
 
#define CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(x, y)
 Helper macro to implement OperateKeystream. More...
 

Enumerations

enum  KeystreamOperationFlags { OUTPUT_ALIGNED =1, INPUT_ALIGNED =2, INPUT_NULL = 4 }
 Keystream operation flags. More...
 
enum  KeystreamOperation {
  WRITE_KEYSTREAM = INPUT_NULL, WRITE_KEYSTREAM_ALIGNED = INPUT_NULL | OUTPUT_ALIGNED, XOR_KEYSTREAM = 0, XOR_KEYSTREAM_INPUT_ALIGNED = INPUT_ALIGNED,
  XOR_KEYSTREAM_OUTPUT_ALIGNED = OUTPUT_ALIGNED, XOR_KEYSTREAM_BOTH_ALIGNED = OUTPUT_ALIGNED | INPUT_ALIGNED
}
 Keystream operation flags. More...
 

Detailed Description

Classes for implementing stream ciphers.

This file contains helper classes for implementing stream ciphers. All this infrastructure may look very complex compared to what's in Crypto++ 4.x, but stream ciphers implementations now support a lot of new functionality, including better performance (minimizing copying), resetting of keys and IVs, and methods to query which features are supported by a cipher.

Here's an explanation of these classes. The word "policy" is used here to mean a class with a set of methods that must be implemented by individual stream cipher implementations. This is usually much simpler than the full stream cipher API, which is implemented by either AdditiveCipherTemplate or CFB_CipherTemplate using the policy. So for example, an implementation of SEAL only needs to implement the AdditiveCipherAbstractPolicy interface (since it's an additive cipher, i.e., it xors a keystream into the plaintext). See this line in seal.h:

    typedef SymmetricCipherFinal<ConcretePolicyHolder<SEAL_Policy<B>, AdditiveCipherTemplate<> > > Encryption;

AdditiveCipherTemplate and CFB_CipherTemplate are designed so that they don't need to take a policy class as a template parameter (although this is allowed), so that their code is not duplicated for each new cipher. Instead they each get a reference to an abstract policy interface by calling AccessPolicy() on itself, so AccessPolicy() must be overriden to return the actual policy reference. This is done by the ConceretePolicyHolder class. Finally, SymmetricCipherFinal implements the constructors and other functions that must be implemented by the most derived class.

Definition in file strciphr.h.

Macro Definition Documentation

#define CRYPTOPP_KEYSTREAM_OUTPUT_XMM (   x,
  i,
 
)
Value:
{\
__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));\
if (x & OUTPUT_ALIGNED) _mm_store_si128((__m128i *)output+i, t);\
else _mm_storeu_si128((__m128i *)output+i, t);}
Output buffer is aligned.
Definition: strciphr.h:82
Input buffer is aligned.
Definition: strciphr.h:84
Input buffer is NULL.
Definition: strciphr.h:86

Helper macro to implement OperateKeystream.

Definition at line 231 of file strciphr.h.

#define CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH (   x,
 
)
Value:
switch (operation) \
{ \
break; \
case XOR_KEYSTREAM: \
input += y; \
break; \
input += y; \
break; \
input += y; \
break; \
break; \
input += y; \
break; \
} \
output += y;
XOR the input buffer and keystream, write to the aligned output buffer.
Definition: strciphr.h:102
XOR the input buffer and keystream, write to the output buffer.
Definition: strciphr.h:98
Wirte the keystream to the output buffer, input is NULL.
Definition: strciphr.h:94
XOR the aligned input buffer and keystream, write to the aligned output buffer.
Definition: strciphr.h:104
Wirte the keystream to the aligned output buffer, input is NULL.
Definition: strciphr.h:96
XOR the aligned input buffer and keystream, write to the output buffer.
Definition: strciphr.h:100

Helper macro to implement OperateKeystream.

Definition at line 237 of file strciphr.h.

Enumeration Type Documentation

Keystream operation flags.

See also
AdditiveCipherAbstractPolicy::GetBytesPerIteration(), AdditiveCipherAbstractPolicy::GetOptimalBlockSize() and AdditiveCipherAbstractPolicy::GetAlignment()
Enumerator
OUTPUT_ALIGNED 

Output buffer is aligned.

INPUT_ALIGNED 

Input buffer is aligned.

INPUT_NULL 

Input buffer is NULL.

Definition at line 80 of file strciphr.h.

Keystream operation flags.

See also
AdditiveCipherAbstractPolicy::GetBytesPerIteration(), AdditiveCipherAbstractPolicy::GetOptimalBlockSize() and AdditiveCipherAbstractPolicy::GetAlignment()
Enumerator
WRITE_KEYSTREAM 

Wirte the keystream to the output buffer, input is NULL.

WRITE_KEYSTREAM_ALIGNED 

Wirte the keystream to the aligned output buffer, input is NULL.

XOR_KEYSTREAM 

XOR the input buffer and keystream, write to the output buffer.

XOR_KEYSTREAM_INPUT_ALIGNED 

XOR the aligned input buffer and keystream, write to the output buffer.

XOR_KEYSTREAM_OUTPUT_ALIGNED 

XOR the input buffer and keystream, write to the aligned output buffer.

XOR_KEYSTREAM_BOTH_ALIGNED 

XOR the aligned input buffer and keystream, write to the aligned output buffer.

Definition at line 92 of file strciphr.h.