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MessageAuthenticationCode Class Reference

#include <cryptlib.h>

Inheritance diagram for MessageAuthenticationCode:

HashTransformation SimpleKeyingInterface Algorithm Clonable MessageAuthenticationCodeTemplate< BASE > MessageAuthenticationCodeTemplate< CBC_MAC_Base< T > > MessageAuthenticationCodeTemplate< DMAC_Base< T > > MessageAuthenticationCodeTemplate< HMAC_Base< T > > MessageAuthenticationCodeTemplate< PanamaMAC_Base< B > > MessageAuthenticationCodeTemplate< XMACC_Base< T > > PanamaMAC_Base< B > List of all members.

Detailed Description

interface for message authentication codes

Definition at line 574 of file cryptlib.h.

Public Types

enum  IV_Requirement {
  STRUCTURED_IV = 0, RANDOM_IV, UNPREDICTABLE_RANDOM_IV, INTERNALLY_GENERATED_IV,
  NOT_RESYNCHRONIZABLE
}

Public Member Functions

virtual void Update (const byte *input, unsigned int length)=0
 process more input

virtual byte * CreateUpdateSpace (unsigned int &size)
 request space to write input into

virtual void Final (byte *digest)
 compute hash for current message, then restart for a new message

virtual void Restart ()
 discard the current state, and restart with a new message

virtual unsigned int DigestSize () const =0
 size of the hash returned by Final()

virtual unsigned int OptimalBlockSize () const
 input to Update() should have length a multiple of this for optimal speed

virtual unsigned int OptimalDataAlignment () const
 returns how input should be aligned for optimal performance

virtual void CalculateDigest (byte *digest, const byte *input, unsigned int length)
 use this if your input is in one piece and you don't want to call Update() and Final() separately

virtual bool Verify (const byte *digest)
 verify that digest is a valid digest for the current message, then reinitialize the object

virtual bool VerifyDigest (const byte *digest, const byte *input, unsigned int length)
 use this if your input is in one piece and you don't want to call Update() and Verify() separately

virtual void TruncatedFinal (byte *digest, unsigned int digestSize)=0
 truncated version of Final()

virtual void CalculateTruncatedDigest (byte *digest, unsigned int digestSize, const byte *input, unsigned int length)
 truncated version of CalculateDigest()

virtual bool TruncatedVerify (const byte *digest, unsigned int digestLength)
 truncated version of Verify()

virtual bool VerifyTruncatedDigest (const byte *digest, unsigned int digestLength, const byte *input, unsigned int length)
 truncated version of VerifyDigest()

virtual std::string AlgorithmName () const
 returns name of this algorithm, not universally implemented yet

virtual ClonableClone () const
 this is not implemented by most classes yet

virtual unsigned int MinKeyLength () const =0
 returns smallest valid key length in bytes */

virtual unsigned int MaxKeyLength () const =0
 returns largest valid key length in bytes */

virtual unsigned int DefaultKeyLength () const =0
 returns default (recommended) key length in bytes */

virtual unsigned int GetValidKeyLength (unsigned int n) const =0
 returns the smallest valid key length in bytes that is >= min(n, GetMaxKeyLength())

virtual bool IsValidKeyLength (unsigned int n) const
 returns whether n is a valid key length

virtual void SetKey (const byte *key, unsigned int length, const NameValuePairs &params=g_nullNameValuePairs)=0
 set or reset the key of this object

void SetKeyWithRounds (const byte *key, unsigned int length, int rounds)
 calls SetKey() with an NameValuePairs object that just specifies "Rounds"

void SetKeyWithIV (const byte *key, unsigned int length, const byte *iv)
 calls SetKey() with an NameValuePairs object that just specifies "IV"

virtual IV_Requirement IVRequirement () const =0
 returns the minimal requirement for secure IVs

bool IsResynchronizable () const
 returns whether this object can be resynchronized (i.e. supports initialization vectors)

bool CanUseRandomIVs () const
 returns whether this object can use random IVs (in addition to ones returned by GetNextIV)

bool CanUsePredictableIVs () const
 returns whether this object can use random but possibly predictable IVs (in addition to ones returned by GetNextIV)

bool CanUseStructuredIVs () const
 returns whether this object can use structured IVs, for example a counter (in addition to ones returned by GetNextIV)

virtual unsigned int IVSize () const
 returns size of IVs used by this object

virtual void Resynchronize (const byte *IV)
 resynchronize with an IV

virtual void GetNextIV (byte *IV)
 get a secure IV for the next message


Protected Member Functions

void ThrowIfInvalidTruncatedSize (unsigned int size) const
void ThrowIfInvalidKeyLength (const Algorithm &algorithm, unsigned int length)
void AssertValidKeyLength (unsigned int length) const


Member Function Documentation

virtual void HashTransformation::Final byte *  digest  )  [inline, virtual, inherited]
 

compute hash for current message, then restart for a new message

Precondition:
size of digest == DigestSize().

Definition at line 509 of file cryptlib.h.

virtual bool HashTransformation::Verify const byte *  digest  )  [inline, virtual, inherited]
 

verify that digest is a valid digest for the current message, then reinitialize the object

Default implementation is to call Final() and do a bitwise comparison between its output and digest.

Definition at line 532 of file cryptlib.h.

virtual void SimpleKeyingInterface::SetKey const byte *  key,
unsigned int  length,
const NameValuePairs params = g_nullNameValuePairs
[pure virtual, inherited]
 

set or reset the key of this object

Parameters:
params is used to specify Rounds, BlockSize, etc

Implemented in MessageAuthenticationCodeTemplate< BASE >, MessageAuthenticationCodeTemplate< CBC_MAC_Base< T > >, MessageAuthenticationCodeTemplate< HMAC_Base< T > >, MessageAuthenticationCodeTemplate< XMACC_Base< T > >, MessageAuthenticationCodeTemplate< DMAC_Base< T > >, and MessageAuthenticationCodeTemplate< PanamaMAC_Base< B > >.

Referenced by SimpleKeyingInterface::SetKeyWithIV(), and SimpleKeyingInterface::SetKeyWithRounds().

bool SimpleKeyingInterface::IsResynchronizable  )  const [inline, inherited]
 

returns whether this object can be resynchronized (i.e. supports initialization vectors)

If this function returns true, and no IV is passed to SetKey() and CanUseStructuredIVs()==true, an IV of all 0's will be assumed.

Definition at line 364 of file cryptlib.h.

References SimpleKeyingInterface::IVRequirement().

virtual void SimpleKeyingInterface::GetNextIV byte *  IV  )  [inline, virtual, inherited]
 

get a secure IV for the next message

This method should be called after you finish encrypting one message and are ready to start the next one. After calling it, you must call SetKey() or Resynchronize() before using this object again. This method is not implemented on decryption objects.

Definition at line 380 of file cryptlib.h.

References SimpleKeyingInterface::GetNextIV().

Referenced by SimpleKeyingInterface::GetNextIV().


The documentation for this class was generated from the following file:
Generated on Fri Aug 13 09:56:58 2004 for Crypto++ by doxygen 1.3.7