Poly1305 message authentication code. More...

#include <poly1305.h>

Inheritance 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
	Create a copy of this object. More...

Public Member Functions inherited from AlgorithmImpl< SimpleKeyingInterfaceImpl< Poly1305_Base< T >, Poly1305_Base< T > >, Poly1305_Base< T > >
std::string	AlgorithmName () const
	The algorithm name. More...

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 initialization vector length for the algorithm. More...

Public Member Functions inherited from Poly1305_Base< T >
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...

std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm. More...

Public Member Functions inherited from SimpleKeyingInterface
virtual size_t	MinKeyLength () const =0
	Returns smallest valid key length. More...

virtual size_t	MaxKeyLength () const =0
	Returns largest valid key length. More...

virtual size_t	DefaultKeyLength () const =0
	Returns default key length. More...

virtual size_t	GetValidKeyLength (size_t keylength) const =0
	Returns a valid key length for the algorithm. More...

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...

virtual IV_Requirement	IVRequirement () const =0
	Minimal requirement for secure IVs. 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...

virtual unsigned int	IVSize () const
	Returns length of the IV accepted by this object. 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...

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

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

Public Member Functions inherited from HashTransformation
HashTransformation &	Ref ()
	Provides a reference to this object. More...

virtual void	Update (const byte *input, size_t length)=0
	Updates a hash with additional input. 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...

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

virtual unsigned int	DigestSize () const =0
	Provides the digest size of the hash. More...

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

virtual unsigned int	BlockSize () const
	Provides the block size of the compression function. 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	TruncatedFinal (byte *digest, size_t digestSize)=0
	Computes 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
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms. More...

virtual std::string	AlgorithmName () const
	Provides the name of this algorithm. More...

virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm. More...

virtual Clonable *	Clone () const
	Copies this object. More...

Static Public Attributes
static const int	DEFAULT_KEYLENGTH =Poly1305_Base<T>::DEFAULT_KEYLENGTH

Static Public Attributes inherited from Poly1305_Base< T >
static const int	DIGESTSIZE =T::BLOCKSIZE

static const int	BLOCKSIZE =T::BLOCKSIZE

Static Public Attributes inherited from FixedKeyLength< 32, SimpleKeyingInterface::UNIQUE_IV, 16 >
static const int	KEYLENGTH
	The default key length used by the algorithm provided as a constant. More...

static const int	MIN_KEYLENGTH
	The minimum key length used by the algorithm provided as a constant. More...

static const int	MAX_KEYLENGTH
	The maximum key length used by the algorithm provided as a constant. More...

static const int	DEFAULT_KEYLENGTH
	The default key length used by the algorithm provided as a constant. More...

static const int	IV_REQUIREMENT
	The default IV requirements for the algorithm provided as a constant. More...

static const int	IV_LENGTH
	The default IV length used by the algorithm provided as a constant. More...

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	StaticAlgorithmName ()
	The algorithm name. More...

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

Static Public Member Functions inherited from FixedKeyLength< 32, SimpleKeyingInterface::UNIQUE_IV, 16 >
static size_t	StaticGetValidKeyLength (size_t keylength)
	The default key length for the algorithm provided by a static function. More...

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.

The key is 32 bytes and a concatenation key = {k,s}, where k is the AES key and r is additional key that gets clamped. The key is clamped internally so there is no need to perform the operation before setting the key.

Each message must have 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 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 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: Each message must have a unique security context. The Poly1305 class does not enforce a fresh key or 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++ 6.0

Definition at line 136 of file poly1305.h.

Constructor & Destructor Documentation

◆ Poly1305() [1/2]

template<class T >

Poly1305< T >::Poly1305 ( )

inline

Construct a Poly1305.

Definition at line 142 of file poly1305.h.

◆ Poly1305() [2/2]

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

The key is 32 bytes and a concatenation key = {k,s}, where k is the AES key and r is additional key that gets clamped. The key is clamped internally so there is no need to perform the operation before setting the key.

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 155 of file poly1305.h.

Member Data Documentation

◆ DEFAULT_KEYLENGTH

template<class T >

const int Poly1305< T >::DEFAULT_KEYLENGTH =Poly1305_Base<T>::DEFAULT_KEYLENGTH

static

Definition at line 139 of file poly1305.h.

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

poly1305.h

Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Poly1305() [1/2]

◆ Poly1305() [2/2]

Member Data Documentation

◆ DEFAULT_KEYLENGTH