ed25519_MessageAccumulator Struct Reference

ed25519 message accumulator More...

#include <xed25519.h>

Inheritance diagram for ed25519_MessageAccumulator:

Public Member Functions
	ed25519_MessageAccumulator ()
	Create a message accumulator.
	ed25519_MessageAccumulator (RandomNumberGenerator &rng)
	Create a message accumulator.
void	Update (const byte *msg, size_t len)
	Add data to the accumulator.
void	Restart ()
	Reset the accumulator.
byte *	signature ()
	Retrieve pointer to signature buffer.
const byte *	signature () const
	Retrieve pointer to signature buffer.
const byte *	data () const
	Retrieve pointer to data buffer.
size_t	size () const
	Retrieve size of data buffer.
Public Member Functions inherited from PK_MessageAccumulator
unsigned int	DigestSize () const
void	TruncatedFinal (byte *digest, size_t digestSize)
Public Member Functions inherited from HashTransformation
HashTransformation &	Ref ()
	Provides a reference to this object.
virtual byte *	CreateUpdateSpace (size_t &size)
	Request space which can be written into by the caller.
virtual void	Final (byte *digest)
	Computes the hash of the current message.
unsigned int	TagSize () const
	Provides the tag size of the hash.
virtual unsigned int	BlockSize () const
	Provides the block size of the compression function.
virtual unsigned int	OptimalBlockSize () const
	Provides the input block size most efficient for this hash.
virtual unsigned int	OptimalDataAlignment () const
	Provides input and output data alignment for optimal performance.
virtual void	CalculateDigest (byte *digest, const byte *input, size_t length)
	Updates the hash with additional input and computes the hash of the current message.
virtual bool	Verify (const byte *digest)
	Verifies the hash of the current message.
virtual bool	VerifyDigest (const byte *digest, const byte *input, size_t length)
	Updates the hash with additional input and verifies the hash of the current message.
virtual void	CalculateTruncatedDigest (byte *digest, size_t digestSize, const byte *input, size_t length)
	Updates the hash with additional input and computes the hash of the current message.
virtual bool	TruncatedVerify (const byte *digest, size_t digestLength)
	Verifies the hash of the current message.
virtual bool	VerifyTruncatedDigest (const byte *digest, size_t digestLength, const byte *input, size_t length)
	Updates the hash with additional input and verifies the hash of the current message.
Public Member Functions inherited from Algorithm
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms.
virtual std::string	AlgorithmName () const
	Provides the name of this algorithm.
virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.
Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

Static Public Attributes
static const int	RESERVE_SIZE =2048+64
static const int	SIGNATURE_LENGTH =64

Detailed Description

ed25519 message accumulator

ed25519 buffers the entire message, and does not digest the message incrementally. You should be careful with large messages like files on-disk. The behavior is by design because Bernstein feels small messages should be authenticated; and larger messages will be digested by the application.

The accumulator is used for signing and verification. The first 64-bytes of storage is reserved for the signature. During signing the signature storage is unused. During verification the first 64 bytes holds the signature. The signature is provided by the PK_Verifier framework and the call to PK_Signer::InputSignature. Member functions data() and size() refer to the accumulated message. Member function signature() refers to the signature with an implicit size of SIGNATURE_LENGTH bytes.

Applications which digest large messages, like an ISO disk file, should take care because the design effectively disgorges the format operation from the signing operation. Put another way, be careful to ensure what you are signing is is in fact a digest of the intended message, and not a different message digest supplied by an attacker.

Definition at line 278 of file xed25519.h.

Constructor & Destructor Documentation

ed25519_MessageAccumulator() [1/2]

ed25519_MessageAccumulator::ed25519_MessageAccumulator ( )

inline

Create a message accumulator.

Definition at line 284 of file xed25519.h.

ed25519_MessageAccumulator() [2/2]

ed25519_MessageAccumulator::ed25519_MessageAccumulator ( RandomNumberGenerator & rng )

inline

Create a message accumulator.

ed25519 does not use a RNG. You can safely use NullRNG() because IsProbablistic returns false.

Definition at line 291 of file xed25519.h.

Member Function Documentation

Update()

void ed25519_MessageAccumulator::Update ( const byte * msg, size_t len )

inlinevirtual

Add data to the accumulator.

Parameters

msg	pointer to the data to accumulate
len	the size of the data, in bytes

Implements HashTransformation.

Definition at line 298 of file xed25519.h.

Restart()

void ed25519_MessageAccumulator::Restart ( )

inlinevirtual

Reset the accumulator.

Reimplemented from HashTransformation.

Definition at line 304 of file xed25519.h.

signature() [1/2]

byte * ed25519_MessageAccumulator::signature ( )

inline

Retrieve pointer to signature buffer.

Returns

pointer to signature buffer

Definition at line 311 of file xed25519.h.

signature() [2/2]

const byte * ed25519_MessageAccumulator::signature ( ) const

inline

Retrieve pointer to signature buffer.

Returns

pointer to signature buffer

Definition at line 317 of file xed25519.h.

data()

const byte * ed25519_MessageAccumulator::data ( ) const

inline

Retrieve pointer to data buffer.

Returns

pointer to data buffer

Definition at line 323 of file xed25519.h.

size()

size_t ed25519_MessageAccumulator::size ( ) const

inline

Retrieve size of data buffer.

Returns

size of the data buffer, in bytes

Definition at line 329 of file xed25519.h.

Member Data Documentation

RESERVE_SIZE

const int ed25519_MessageAccumulator::RESERVE_SIZE =2048+64

static

Definition at line 280 of file xed25519.h.

SIGNATURE_LENGTH

const int ed25519_MessageAccumulator::SIGNATURE_LENGTH =64

static

Definition at line 281 of file xed25519.h.

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The documentation for this struct was generated from the following file:

• xed25519.h