SHA2 Class Reference

#include <sha.h>

Inheritance diagram for SHA2:

Collaboration diagram for SHA2:

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Detailed Description

Implementation of the Extended NIST Secure Hash Algorithms (SHA-256/-384/-512), FIPS 180-2.

Usage flow:
  SHA2()     // construct a new SHA2 object
  add()      // call as many times as necessary to process data
  final()    // finalize message digest computation
  result()   // obtain resulting hash value

Recommendations for strict FIPS 140-1 compliance:
  All public data members and methods of the SHA2 class can be used 
  by an application requiring FIPS 140-1 compliance.

Sample code illustrating the use of this class appears in the Cookbook section Using the Message Digest Functions.

References

SHA-256/-384/-512 are specified in:

• FIPS 180-2

• original NIST Specifications

Public Member Functions
	SHA2 (int version)
	Constructor used to create a new object initialized for SHA-256, -384 or -512.
	~SHA2 ()
	Destructor. Calls clear();.
int	add (char c)
	Update message digest computation with a single byte.
int	add (int bytes, const char *buf)
	Update message digest computation with a buffer.
int	final (void)
	Finalize the message digest computation.
const char *	result (void) const
	Get a pointer to the final message digest.
int	length () const
	Get the length in bytes of a message digest.
int	blocksize () const
	Get the algorithm block size.
template<class T>
T	to () const
	Get a type T representation of the message digest.
str	tostr () const
	Get a str representation of the message digest.
void	clear (void)
	clear

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Constructor & Destructor Documentation

SHA2

(

int

version

)

[inline, explicit]

Constructor used to create a new object initialized for SHA-256, -384 or -512.

Parameters:

version

indicator: 2 for SHA-256, 3 for SHA-384, 5 (or any other value) for SHA-512

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Member Function Documentation

int add	(	int	bytes,
		const char *	buf
	)

Update message digest computation with a buffer.

Parameters:

	bytes	the number of bytes in the input buffer
	buf	a pointer to the input buffer

Returns:

0 (success)
CDK_ERROR_STATE
CDK_INVALID_PTR

int add

(

char

c

)

[inline]

Update message digest computation with a single byte.

Parameters:

c

the byte to be hashed

Returns:

0 (success)
CDK_ERROR_STATE

int blocksize

(

)

const [inline]

Get the algorithm block size.

Returns:

the algorithm's block size in bytes (64 or 128)

void clear

(

void

)

clear

Remarks:

Modifies: clear() called to initialize the object. vers doesn't change.

int final

(

void

)

Finalize the message digest computation.

Returns:

0 (success)
CDK_ERROR_STATE

int length

(

)

const

Get the length in bytes of a message digest.

Returns:

the expected number of output bytes (32, 48, or 64)

const char* result

(

void

)

const

Get a pointer to the final message digest.

Returns:

a pointer to the message digest
(NULL, if the CDK is in its hard error state)

T to

(

)

const [inline]

Get a type T representation of the message digest.

Returns:

an object of type T representating the message digest

str tostr

(

)

const

Get a str representation of the message digest.

Returns:

a str containing the string representation of the message digest.

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

• sha.h

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ISC Cryptographic Development Kit - User's Guide
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