Poly1305 message authentication code. More...

#include <poly1305.h>

Inheritance diagram for Poly1305< T >:

Collaboration diagram for Poly1305< T >:

Public Member Functions
	Poly1305 ()
	Construct a Poly1305. More...

	Poly1305 (const byte key, size_t keyLength=DEFAULT_KEYLENGTH, const byte nonce=NULL, size_t nonceLength=0)
	Construct a Poly1305. More...

Public Member Functions inherited from MessageAuthenticationCodeFinal< Poly1305_Base< T > >
	MessageAuthenticationCodeFinal ()
	Construct a default MessageAuthenticationCodeFinal. More...

	MessageAuthenticationCodeFinal (const byte *key)
	Construct a BlockCipherFinal. More...

	MessageAuthenticationCodeFinal (const byte *key, size_t length)
	Construct a BlockCipherFinal. More...

Public Member Functions inherited from ClonableImpl< MessageAuthenticationCodeFinal< Poly1305_Base< T > >, MessageAuthenticationCodeImpl< Poly1305_Base< T > > >
Clonable *	Clone () const

Public Member Functions inherited from AlgorithmImpl< SimpleKeyingInterfaceImpl< Poly1305_Base< T >, Poly1305_Base< T > >, Poly1305_Base< T > >
std::string	AlgorithmName () const

Public Member Functions inherited from SimpleKeyingInterfaceImpl< Poly1305_Base< T >, Poly1305_Base< T > >
size_t	MinKeyLength () const
	The minimum key length used by the algorithm. More...

size_t	MaxKeyLength () const
	The maximum key length used by the algorithm. More...

size_t	DefaultKeyLength () const
	The default key length used by the algorithm. More...

size_t	GetValidKeyLength (size_t keylength) const
	Provides a valid key length for the algorithm. More...

SimpleKeyingInterface::IV_Requirement	IVRequirement () const
	The default IV requirements for the algorithm. More...

unsigned int	IVSize () const
	The default initialization vector length for the algorithm. More...

Public Member Functions inherited from Poly1305_Base< T >
	Poly1305_Base ()

void	Resynchronize (const byte *iv, int ivLength=-1)
	Resynchronize with an IV. More...

void	GetNextIV (RandomNumberGenerator &rng, byte *iv)
	Retrieves a secure IV for the next message. More...

void	UncheckedSetKey (const byte *key, unsigned int length, const NameValuePairs &params)
	Sets the key for this object without performing parameter validation. More...

void	Update (const byte *input, size_t length)
	Updates a hash with additional input. More...

void	TruncatedFinal (byte *mac, size_t size)
	Computes the hash of the current message. More...

void	Restart ()
	Restart the hash. More...

unsigned int	BlockSize () const
	Provides the block size of the compression function. More...

unsigned int	DigestSize () const
	Provides the digest size of the hash. More...

Public Member Functions inherited from FixedKeyLength< 32, SimpleKeyingInterface::UNIQUE_IV, 16 >
CRYPTOPP_STATIC_CONSTEXPR size_t CRYPTOPP_API	StaticGetValidKeyLength (size_t keylength)
	The default key length used by the algorithm provided as a constant. More...

Public Member Functions inherited from SimpleKeyingInterface
virtual	~SimpleKeyingInterface ()

virtual bool	IsValidKeyLength (size_t keylength) const
	Returns whether keylength is a valid key length. More...

virtual void	SetKey (const byte *key, size_t length, const NameValuePairs &params=g_nullNameValuePairs)
	Sets or reset the key of this object. More...

void	SetKeyWithRounds (const byte *key, size_t length, int rounds)
	Sets or reset the key of this object. More...

void	SetKeyWithIV (const byte key, size_t length, const byte iv, size_t ivLength)
	Sets or reset the key of this object. More...

void	SetKeyWithIV (const byte key, size_t length, const byte iv)
	Sets or reset the key of this object. More...

bool	IsResynchronizable () const
	Determines if the object can be resynchronized. More...

bool	CanUseRandomIVs () const
	Determines if the object can use random IVs. More...

bool	CanUsePredictableIVs () const
	Determines if the object can use random but possibly predictable IVs. More...

bool	CanUseStructuredIVs () const
	Determines if the object can use structured IVs. More...

unsigned int	DefaultIVLength () const
	Provides the default size of an IV. More...

virtual unsigned int	MinIVLength () const
	Provides the minimum size of an IV. More...

virtual unsigned int	MaxIVLength () const
	Provides the maximum size of an IV. More...

Public Member Functions inherited from HashTransformation
virtual	~HashTransformation ()

HashTransformation &	Ref ()
	Provides a reference to this object. More...

virtual byte *	CreateUpdateSpace (size_t &size)
	Request space which can be written into by the caller. More...

virtual void	Final (byte *digest)
	Computes the hash of the current message. More...

unsigned int	TagSize () const
	Provides the tag size of the hash. More...

virtual unsigned int	OptimalBlockSize () const
	Provides the input block size most efficient for this hash. More...

virtual unsigned int	OptimalDataAlignment () const
	Provides input and output data alignment for optimal performance. More...

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. More...

virtual bool	Verify (const byte *digest)
	Verifies the hash of the current message. More...

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. More...

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. More...

virtual bool	TruncatedVerify (const byte *digest, size_t digestLength)
	Verifies the hash of the current message. More...

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. More...

Public Member Functions inherited from Algorithm
virtual	~Algorithm ()

	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms. More...

Public Member Functions inherited from Clonable
virtual	~Clonable ()

Additional Inherited Members
Public Types inherited from SimpleKeyingInterface
enum	IV_Requirement { UNIQUE_IV = 0, RANDOM_IV, UNPREDICTABLE_RANDOM_IV, INTERNALLY_GENERATED_IV, NOT_RESYNCHRONIZABLE }
	Secure IVs requirements as enumerated values. More...

Static Public Member Functions inherited from AlgorithmImpl< SimpleKeyingInterfaceImpl< Poly1305_Base< T >, Poly1305_Base< T > >, Poly1305_Base< T > >
static std::string CRYPTOPP_API	StaticAlgorithmName ()

Static Public Member Functions inherited from Poly1305_Base< T >
static std::string	StaticAlgorithmName ()

Protected Member Functions inherited from Poly1305_Base< T >
void	HashBlocks (const byte *input, size_t length, word32 padbit)

void	HashFinal (byte *mac, size_t length)

Protected Member Functions inherited from MessageAuthenticationCode
const Algorithm &	GetAlgorithm () const
	Returns the base class Algorithm. More...

Protected Member Functions inherited from SimpleKeyingInterface
void	ThrowIfInvalidKeyLength (size_t length)
	Validates the key length. More...

void	ThrowIfResynchronizable ()
	Validates the object. More...

void	ThrowIfInvalidIV (const byte *iv)
	Validates the IV. More...

size_t	ThrowIfInvalidIVLength (int length)
	Validates the IV length. More...

const byte *	GetIVAndThrowIfInvalid (const NameValuePairs &params, size_t &size)
	Retrieves and validates the IV. More...

void	AssertValidKeyLength (size_t length) const
	Validates the key length. More...

Protected Member Functions inherited from HashTransformation
void	ThrowIfInvalidTruncatedSize (size_t size) const
	Validates a truncated digest size. More...

Protected Attributes inherited from Poly1305_Base< T >
T::Encryption	m_cipher

FixedSizeAlignedSecBlock< word32, 5 >	m_h

FixedSizeAlignedSecBlock< word32, 4 >	m_r

FixedSizeAlignedSecBlock< word32, 4 >	m_n

FixedSizeAlignedSecBlock< byte, BLOCKSIZE >	m_acc

size_t	m_idx

bool	m_used

Detailed Description

template<class T>
class Poly1305< T >

Poly1305 message authentication code.

Template Parameters

T	class derived from BlockCipherDocumentation with 16-byte key and 16-byte blocksize

Poly1305-AES is a state-of-the-art message-authentication code suitable for a wide variety of applications. Poly1305-AES computes a 16-byte authenticator of a variable-length message, using a 16-byte AES key, a 16-byte additional key, and a 16-byte nonce.

Each message must use a unique security context, which means either the key or nonce must be changed after each message. It can be accomplished in one of two ways. First, you can create a new Poly1305 object with a key and nonce each time its needed.

  SecByteBlock key(32), nonce(16);
  prng.GenerateBlock(key, key.size());
  prng.GenerateBlock(nonce, nonce.size());

  Poly1305<AES> poly1305(key, key.size(), nonce, nonce.size());
  poly1305.Update(...);
  poly1305.Final(...);

Second, you can create a Poly1305 object, reuse the key, and set a fresh nonce for each message. The second and subsequent nonces can be generated directly using a RandomNumberGenerator() derived class; or it can be generated using GetNextIV().

  SecByteBlock key(32), nonce(16);
  prng.GenerateBlock(key, key.size());
  prng.GenerateBlock(nonce, nonce.size());

  // First message
  Poly1305<AES> poly1305(key, key.size());
  poly1305.Resynchronize(nonce);
  poly1305.Update(...);
  poly1305.Final(...);

  // Second message
  poly1305.GetNextIV(prng, nonce);
  poly1305.Resynchronize(nonce);
  poly1305.Update(...);
  poly1305.Final(...);
  ...

Warning: The Poly1305 class does not enforce a fresh nonce for each message. The source code will assert in debug builds to alert of nonce reuse. No action is taken in release builds.

See also: Daniel J. Bernstein The Poly1305-AES Message-Authentication Code (20050329) and Andy Polyakov Poly1305 Revised

Since: Crypto++ 5.7

Definition at line 147 of file poly1305.h.

Constructor & Destructor Documentation

template<class T>

Poly1305< T >::Poly1305 ( )

inline

Construct a Poly1305.

Definition at line 153 of file poly1305.h.

template<class T>

Poly1305< T >::Poly1305	(	const byte *	key,
		size_t	keyLength = `DEFAULT_KEYLENGTH`,
		const byte *	nonce = `NULL`,
		size_t	nonceLength = `0`
	)

inline

Construct a Poly1305.

Parameters

key	a byte array used to key the cipher
keyLength	the size of the byte array, in bytes
nonce	a byte array used to key the cipher
nonceLength	the size of the byte array, in bytes

key is the 32-byte key composed of the 16-byte AES key and the 16 additional key bytes used for r.

Each message requires a unique security context. You can use GetNextIV() and Resynchronize() to set a new nonce under a key for a message.

Definition at line 164 of file poly1305.h.

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

src/cryptopp/poly1305.h

Public Member Functions

Additional Inherited Members

Detailed Description

template<class T> class Poly1305< T >

Constructor & Destructor Documentation

template<class T>
class Poly1305< T >