Interface for authenticated encryption modes of operation. More...

#include <cryptlib.h>

Inheritance diagram for AuthenticatedSymmetricCipher:

Classes
class	BadState
	Exception thrown when the object is in the wrong state for the operation. More...

Public Member Functions
virtual lword	MaxHeaderLength () const =0
	Provides the maximum length of AAD that can be input.

virtual lword	MaxMessageLength () const =0
	Provides the maximum length of encrypted data.

virtual lword	MaxFooterLength () const
	Provides the maximum length of AAD.

virtual bool	NeedsPrespecifiedDataLengths () const
	Determines if data lengths must be specified prior to inputting data.

void	SpecifyDataLengths (lword headerLength, lword messageLength, lword footerLength=0)
	Prescribes the data lengths.

virtual void	EncryptAndAuthenticate (byte ciphertext, byte mac, size_t macSize, const byte iv, int ivLength, const byte header, size_t headerLength, const byte *message, size_t messageLength)
	Encrypts and calculates a MAC in one call.

virtual bool	DecryptAndVerify (byte message, const byte mac, size_t macSize, const byte iv, int ivLength, const byte header, size_t headerLength, const byte *ciphertext, size_t ciphertextLength)
	Decrypts and verifies a MAC in one call.

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 SimpleKeyingInterface
virtual size_t	MinKeyLength () const =0
	Returns smallest valid key length.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

virtual void	Restart ()
	Restart the hash.

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

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	TruncatedFinal (byte *digest, size_t digestSize)=0
	Computes 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.

Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

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

virtual unsigned int	MandatoryBlockSize () const
	Provides the mandatory block size of the cipher.

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

virtual unsigned int	GetOptimalBlockSizeUsed () const
	Provides the number of bytes used in the current block when processing at optimal block size.

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

virtual void	ProcessData (byte outString, const byte inString, size_t length)=0
	Encrypt or decrypt an array of bytes.

virtual size_t	ProcessLastBlock (byte outString, size_t outLength, const byte inString, size_t inLength)
	Encrypt or decrypt the last block of data.

virtual unsigned int	MinLastBlockSize () const
	Provides the size of the last block.

virtual bool	IsLastBlockSpecial () const
	Determines if the last block receives special processing.

void	ProcessString (byte *inoutString, size_t length)
	Encrypt or decrypt a string of bytes.

void	ProcessString (byte outString, const byte inString, size_t length)
	Encrypt or decrypt a string of bytes.

byte	ProcessByte (byte input)
	Encrypt or decrypt a byte.

virtual bool	IsRandomAccess () const =0
	Determines whether the cipher supports random access.

virtual void	Seek (lword pos)
	Seek to an absolute position.

virtual bool	IsSelfInverting () const =0
	Determines whether the cipher is self-inverting.

virtual bool	IsForwardTransformation () const =0
	Determines if the cipher is being operated in its forward direction.

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...

Detailed Description

Interface for authenticated encryption modes of operation.

AuthenticatedSymmetricCipher() provides the interface for one direction (encryption or decryption) of a stream cipher or block cipher mode with authentication. The StreamTransformation() part of this interface is used to encrypt or decrypt the data. The MessageAuthenticationCode() part of the interface is used to input additional authenticated data (AAD), which is MAC'ed but not encrypted. The MessageAuthenticationCode() part is also used to generate and verify the MAC.

Crypto++ provides four authenticated encryption modes of operation - CCM, EAX, GCM and OCB mode. All modes implement AuthenticatedSymmetricCipher() and the motivation for the API, like calling AAD a "header", can be found in Bellare, Rogaway and Wagner's The EAX Mode of Operation. The EAX paper suggested a basic API to help standardize AEAD schemes in software and promote adoption of the modes.

See also: Authenticated Encryption on the Crypto++ wiki.

Since: Crypto++ 5.6.0

Definition at line 1325 of file cryptlib.h.

Constructor & Destructor Documentation

◆ ~AuthenticatedSymmetricCipher()

virtual AuthenticatedSymmetricCipher::~AuthenticatedSymmetricCipher ( )

inlinevirtual

Definition at line 1328 of file cryptlib.h.

Member Function Documentation

◆ MaxHeaderLength()

virtual lword AuthenticatedSymmetricCipher::MaxHeaderLength ( ) const

pure virtual

Provides the maximum length of AAD that can be input.

Returns: the maximum length of AAD that can be input before the encrypted data

Implemented in CCM_Base, ChaCha20Poly1305_Base, XChaCha20Poly1305_Base, EAX_Base, and GCM_Base.

◆ MaxMessageLength()

virtual lword AuthenticatedSymmetricCipher::MaxMessageLength ( ) const

pure virtual

Provides the maximum length of encrypted data.

Returns: the maximum length of encrypted data

Implemented in CCM_Base, ChaCha20Poly1305_Base, XChaCha20Poly1305_Base, EAX_Base, and GCM_Base.

◆ MaxFooterLength()

virtual lword AuthenticatedSymmetricCipher::MaxFooterLength ( ) const

inlinevirtual

Provides the maximum length of AAD.

Returns: the maximum length of AAD that can be input after the encrypted data

Reimplemented in ChaCha20Poly1305_Base, and XChaCha20Poly1305_Base.

Definition at line 1350 of file cryptlib.h.

◆ NeedsPrespecifiedDataLengths()

virtual bool AuthenticatedSymmetricCipher::NeedsPrespecifiedDataLengths ( ) const

inlinevirtual

Determines if data lengths must be specified prior to inputting data.

Returns: true if the data lengths are required before inputting data, false otherwise

if this function returns true, SpecifyDataLengths() must be called before attempting to input data. This is the case for some schemes, such as CCM.

See also: SpecifyDataLengths()

Reimplemented in CCM_Base.

Definition at line 1357 of file cryptlib.h.

◆ SpecifyDataLengths()

void AuthenticatedSymmetricCipher::SpecifyDataLengths	(	lword	headerLength,
		lword	messageLength,
		lword	footerLength = 0 )

Prescribes the data lengths.

Parameters

headerLength	size of data before message is input, in bytes
messageLength	size of the message, in bytes
footerLength	size of data after message is input, in bytes

SpecifyDataLengths() only needs to be called if NeedsPrespecifiedDataLengths() returns true. If true, then headerLength will be validated against MaxHeaderLength(), messageLength will be validated against MaxMessageLength(), and footerLength will be validated against MaxFooterLength().

See also: NeedsPrespecifiedDataLengths()

◆ EncryptAndAuthenticate()

virtual void AuthenticatedSymmetricCipher::EncryptAndAuthenticate	(	byte *	ciphertext,
		byte *	mac,
		size_t	macSize,
		const byte *	iv,
		int	ivLength,
		const byte *	header,
		size_t	headerLength,
		const byte *	message,
		size_t	messageLength )

virtual

Encrypts and calculates a MAC in one call.

Parameters

ciphertext	the encryption buffer
mac	the mac buffer
macSize	the size of the MAC buffer, in bytes
iv	the iv buffer
ivLength	the size of the IV buffer, in bytes
header	the AAD buffer
headerLength	the size of the AAD buffer, in bytes
message	the message buffer
messageLength	the size of the messagetext buffer, in bytes

EncryptAndAuthenticate() encrypts and generates the MAC in one call. The function truncates the MAC if macSize < TagSize().

Reimplemented in ChaCha20Poly1305_Base, and XChaCha20Poly1305_Base.

◆ DecryptAndVerify()

virtual bool AuthenticatedSymmetricCipher::DecryptAndVerify	(	byte *	message,
		const byte *	mac,
		size_t	macSize,
		const byte *	iv,
		int	ivLength,
		const byte *	header,
		size_t	headerLength,
		const byte *	ciphertext,
		size_t	ciphertextLength )

virtual

Decrypts and verifies a MAC in one call.

Parameters

message	the decryption buffer
mac	the mac buffer
macSize	the size of the MAC buffer, in bytes
iv	the iv buffer
ivLength	the size of the IV buffer, in bytes
header	the AAD buffer
headerLength	the size of the AAD buffer, in bytes
ciphertext	the ciphertext buffer
ciphertextLength	the size of the ciphertext buffer, in bytes

Returns: true if the MAC is valid and the decoding succeeded, false otherwise

DecryptAndVerify() decrypts and verifies the MAC in one call. message is a decryption buffer and should be at least as large as the ciphertext buffer.

The function returns true iff MAC is valid. DecryptAndVerify() assumes the MAC is truncated if macLength < TagSize().

Reimplemented in ChaCha20Poly1305_Base, and XChaCha20Poly1305_Base.

◆ AlgorithmName()

virtual std::string AuthenticatedSymmetricCipher::AlgorithmName ( ) const

virtual

Provides the name of this algorithm.

Returns: the standard algorithm name

The standard algorithm name can be a name like AES or AES/GCM. Some algorithms do not have standard names yet. For example, there is no standard algorithm name for Shoup's ECIES.

Reimplemented from Algorithm.

Reimplemented in CCM_Base, ChaCha20Poly1305_Base, XChaCha20Poly1305_Base, EAX_Base, and GCM_Base.

◆ AlgorithmProvider()

virtual std::string AuthenticatedSymmetricCipher::AlgorithmProvider ( ) const

inlinevirtual

Retrieve the provider of this algorithm.

Returns: the algorithm provider

The algorithm provider can be a name like "C++", "SSE", "NEON", "AESNI", "ARMv8" and "Power8". C++ is standard C++ code. Other labels, like SSE, usually indicate a specialized implementation using instructions from a higher instruction set architecture (ISA). Future labels may include external hardware like a hardware security module (HSM).

Generally speaking Wei Dai's original IA-32 ASM code falls under "SSE2". Labels like "SSSE3" and "SSE4.1" follow after Wei's code and use intrinsics instead of ASM.

Algorithms which combine different instructions or ISAs provide the dominant one. For example on x86 AES/GCM returns "AESNI" rather than "CLMUL" or "AES+SSE4.1" or "AES+CLMUL" or "AES+SSE4.1+CLMUL".

Note: Provider is not universally implemented yet.

Since: Crypto++ 8.0

Reimplemented from Algorithm.

Reimplemented in CCM_Base, ChaCha20Poly1305_Base, XChaCha20Poly1305_Base, EAX_Base, EAX_Final< T_BlockCipher, T_IsEncryption >, and GCM_Base.

Definition at line 1423 of file cryptlib.h.

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

cryptlib.h

Classes

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~AuthenticatedSymmetricCipher()

Member Function Documentation

◆ MaxHeaderLength()

◆ MaxMessageLength()

◆ MaxFooterLength()

◆ NeedsPrespecifiedDataLengths()

◆ SpecifyDataLengths()

◆ EncryptAndAuthenticate()

◆ DecryptAndVerify()

◆ AlgorithmName()

◆ AlgorithmProvider()