Crypto++  5.6.5
Free C++ class library of cryptographic schemes
Public Member Functions | List of all members
HashTransformation Class Referenceabstract

Interface for hash functions and data processing part of MACs. More...

+ Inheritance diagram for HashTransformation:

Public Member Functions

HashTransformationRef ()
 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...
 
- Public Member Functions inherited from Clonable
virtual ClonableClone () const
 Copies this object. More...
 

Detailed Description

Interface for hash functions and data processing part of MACs.

HashTransformation objects are stateful. They are created in an initial state, change state as Update() is called, and return to the initial state when Final() is called. This interface allows a large message to be hashed in pieces by calling Update() on each piece followed by calling Final().

See also
HashFilter(), HashVerificationFilter()

Definition at line 930 of file cryptlib.h.

Member Function Documentation

HashTransformation& HashTransformation::Ref ( )
inline

Provides a reference to this object.

Returns
A reference to this object

Useful for passing a temporary object to a function that takes a non-const reference

Definition at line 938 of file cryptlib.h.

virtual void HashTransformation::Update ( const byte *  input,
size_t  length 
)
pure virtual
virtual byte* HashTransformation::CreateUpdateSpace ( size_t &  size)
inlinevirtual

Request space which can be written into by the caller.

Parameters
sizethe requested size of the buffer

The purpose of this method is to help avoid extra memory allocations.

size is an IN and OUT parameter and used as a hint. When the call is made, size is the requested size of the buffer. When the call returns, size is the size of the array returned to the caller.

The base class implementation sets size to 0 and returns NULL.

Note
Some objects, like ArraySink, cannot create a space because its fixed.

Reimplemented in IteratedHashBase< word32, HashTransformation >, IteratedHashBase< T_HashWordType, HashTransformation >, IteratedHashBase< word32, MessageAuthenticationCode >, IteratedHashBase< word64, HashTransformation >, and IteratedHashBase< word64, MessageAuthenticationCode >.

Definition at line 953 of file cryptlib.h.

virtual void HashTransformation::Final ( byte *  digest)
inlinevirtual

Computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash

Final() restarts the hash for a new message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 960 of file cryptlib.h.

virtual void HashTransformation::Restart ( )
inlinevirtual
virtual unsigned int HashTransformation::DigestSize ( ) const
pure virtual

Provides the digest size of the hash.

Returns
the digest size of the hash.

Implemented in PK_MessageAccumulator, BLAKE2_Base< W, T_64bit >, BLAKE2_Base< word32, false >, BLAKE2_Base< word64, true >, IteratedHashWithStaticTransform< T_HashWordType, T_Endianness, T_BlockSize, T_StateSize, T_Transform, T_DigestSize, T_StateAligned >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 32, RIPEMD256 >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 16, MD5 >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 16, MD4 >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 40, RIPEMD320 >, IteratedHashWithStaticTransform< word32, BigEndian, 64, 20, SHA1 >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 16, RIPEMD128 >, IteratedHashWithStaticTransform< word32, BigEndian, 64, 32, SHA224, 28, true >, IteratedHashWithStaticTransform< word32, BigEndian, 64, 32, SHA256, 32, true >, IteratedHashWithStaticTransform< word32, LittleEndian, 64, 20, RIPEMD160 >, IteratedHashWithStaticTransform< word64, LittleEndian, 64, 24, Tiger >, IteratedHashWithStaticTransform< word64, BigEndian, 128, 64, SHA384, 48,(0|0)>, IteratedHashWithStaticTransform< word64, BigEndian, 64, 64, Whirlpool >, IteratedHashWithStaticTransform< word64, BigEndian, 128, 64, SHA512, 64,(0|0)>, Poly1305_Base< T >, CRC32C, GCM_Base, Keccak, CCM_Base, EAX_Base, Weak::PanamaHash< B >, SHA3, TruncatedHashTemplate< T >, CRC32, VMAC_Base, DMAC_Base< T >, HMAC_Base, CMAC_Base, CBC_MAC_Base, TTMAC_Base, Adler32, Weak::MD2, and NullHash.

unsigned int HashTransformation::TagSize ( ) const
inline

Provides the tag size of the hash.

Returns
the tag size of the hash.

Same as DigestSize().

Definition at line 975 of file cryptlib.h.

virtual unsigned int HashTransformation::BlockSize ( ) const
inlinevirtual

Provides the block size of the compression function.

Returns
the block size of the compression function, in bytes

BlockSize() will return 0 if the hash is not block based. For example, SHA3 is a recursive hash (not an iterative hash), and it does not have a block size.

Reimplemented in IteratedHash< word64, LittleEndian, T_BlockSize >, IteratedHash< T_HashWordType, T_Endianness, T_BlockSize >, IteratedHash< word32, LittleEndian, T_BlockSize >, IteratedHash< word32, LittleEndian, 64, MessageAuthenticationCode >, IteratedHash< word32, BigEndian, T_BlockSize >, IteratedHash< word32, NativeByteOrder, 32 >, IteratedHash< word64, BigEndian, T_BlockSize >, Keccak_Final< T_DigestSize >, Poly1305_Base< T >, SHA3_Final< T_DigestSize >, VMAC_Base, and Weak::MD2.

Definition at line 981 of file cryptlib.h.

virtual unsigned int HashTransformation::OptimalBlockSize ( ) const
inlinevirtual

Provides the input block size most efficient for this hash.

Returns
The input block size that is most efficient for the cipher

The base class implementation returns MandatoryBlockSize().

Optimal input length is n * OptimalBlockSize() - GetOptimalBlockSizeUsed() for any n > 0.

Reimplemented in IteratedHashBase< word32, HashTransformation >, IteratedHashBase< T_HashWordType, HashTransformation >, IteratedHashBase< word32, MessageAuthenticationCode >, IteratedHashBase< word64, HashTransformation >, IteratedHashBase< word64, MessageAuthenticationCode >, CMAC_Base, and HMAC_Base.

Definition at line 988 of file cryptlib.h.

unsigned int HashTransformation::OptimalDataAlignment ( ) const
virtual
virtual void HashTransformation::CalculateDigest ( byte *  digest,
const byte *  input,
size_t  length 
)
inlinevirtual

Updates the hash with additional input and computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash
inputthe additional input as a buffer
lengththe size of the buffer, in bytes

Use this if your input is in one piece and you don't want to call Update() and Final() separately

CalculateDigest() restarts the hash for the next message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 1003 of file cryptlib.h.

virtual bool HashTransformation::Verify ( const byte *  digest)
inlinevirtual

Verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if the existing hash's size exceeds DigestSize()

Verify() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

Verify() restarts the hash for the next message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 1015 of file cryptlib.h.

virtual bool HashTransformation::VerifyDigest ( const byte *  digest,
const byte *  input,
size_t  length 
)
inlinevirtual

Updates the hash with additional input and verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
inputthe additional input as a buffer
lengththe size of the buffer, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if the existing hash's size exceeds DigestSize()

Use this if your input is in one piece and you don't want to call Update() and Verify() separately

VerifyDigest() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

VerifyDigest() restarts the hash for the next message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 1031 of file cryptlib.h.

virtual void HashTransformation::TruncatedFinal ( byte *  digest,
size_t  digestSize 
)
pure virtual
virtual void HashTransformation::CalculateTruncatedDigest ( byte *  digest,
size_t  digestSize,
const byte *  input,
size_t  length 
)
inlinevirtual

Updates the hash with additional input and computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash
digestSizethe length of the truncated hash, in bytes
inputthe additional input as a buffer
lengththe size of the buffer, in bytes

Use this if your input is in one piece and you don't want to call Update() and CalculateDigest() separately.

CalculateTruncatedDigest() restarts the hash for the next message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 1051 of file cryptlib.h.

bool HashTransformation::TruncatedVerify ( const byte *  digest,
size_t  digestLength 
)
virtual

Verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
digestLengththe size of the truncated hash, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if digestLength exceeds DigestSize()

TruncatedVerify() is a truncated version of Verify(). It can operate on a buffer smaller than DigestSize(). However, digestLength cannot exceed DigestSize().

Verify() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

TruncatedVerify() restarts the hash for the next message.

Reimplemented in TruncatedHashTemplate< T >, and NullHash.

Definition at line 408 of file cryptlib.cpp.

virtual bool HashTransformation::VerifyTruncatedDigest ( const byte *  digest,
size_t  digestLength,
const byte *  input,
size_t  length 
)
inlinevirtual

Updates the hash with additional input and verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
digestLengththe size of the truncated hash, in bytes
inputthe additional input as a buffer
lengththe size of the buffer, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if digestLength exceeds DigestSize()

Use this if your input is in one piece and you don't want to call Update() and TruncatedVerify() separately.

VerifyTruncatedDigest() is a truncated version of VerifyDigest(). It can operate on a buffer smaller than DigestSize(). However, digestLength cannot exceed DigestSize().

VerifyTruncatedDigest() restarts the hash for the next message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

Definition at line 1080 of file cryptlib.h.


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