Abstract base class for block ciphers. More...

#include <BlockCipher.h>

Inheritance diagram for BlockCipher:

Public Member Functions
	BlockCipher ()
	Constructs a block cipher.

virtual	~BlockCipher ()
	Destroys this block cipher object. More...

virtual size_t	blockSize () const =0
	Size of a single block processed by this cipher, in bytes. More...

virtual size_t	keySize () const =0
	Default size of the key for this block cipher, in bytes. More...

virtual bool	setKey (const uint8_t *key, size_t len)=0
	Sets the key to use for future encryption and decryption operations. More...

virtual void	encryptBlock (uint8_t output, const uint8_t input)=0
	Encrypts a single block using this cipher. More...

virtual void	decryptBlock (uint8_t output, const uint8_t input)=0
	Decrypts a single block using this cipher. More...

virtual void	clear ()=0
	Clears all security-sensitive state from this block cipher. More...

Detailed Description

Abstract base class for block ciphers.

Block ciphers always operate in electronic codebook (ECB) mode. Higher-level classes such as CFB128 and CTR128 wrap the block cipher to create more useful classes for encryption and decryption of bulk data.

References: http://en.wikipedia.org/wiki/Block_cipher, http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29

Definition at line 29 of file BlockCipher.h.

Constructor & Destructor Documentation

BlockCipher::~BlockCipher ( )

virtual

Destroys this block cipher object.

Subclasses are responsible for clearing temporary key schedules and other buffers so as to avoid leaking sensitive information.

See Also: clear()

Definition at line 52 of file BlockCipher.cpp.

Member Function Documentation

size_t BlockCipher::blockSize ( ) const

pure virtual

Size of a single block processed by this cipher, in bytes.

Returns: Returns the size of a block in bytes.

See Also: keySize(), encryptBlock()

Implemented in Speck, and AESCommon.

void BlockCipher::clear ( )

pure virtual

Clears all security-sensitive state from this block cipher.

Security-sensitive information includes key schedules and any temporary state that is used by encryptBlock() or decryptBlock() which is stored in the object itself.

See Also: setKey(), encryptBlock(), decryptBlock()

Implemented in Speck, and AESCommon.

void BlockCipher::decryptBlock	(	uint8_t *	output,
		const uint8_t *	input
	)

pure virtual

Decrypts a single block using this cipher.

Parameters

output	The output buffer to put the plaintext into. Must be at least blockSize() bytes in length.
input	The input buffer to read the ciphertext from which is allowed to overlap with output. Must be at least blockSize() bytes in length.

See Also: encryptBlock(), blockSize()

Implemented in Speck, and AESCommon.

void BlockCipher::encryptBlock	(	uint8_t *	output,
		const uint8_t *	input
	)

pure virtual

Encrypts a single block using this cipher.

Parameters

output	The output buffer to put the ciphertext into. Must be at least blockSize() bytes in length.
input	The input buffer to read the plaintext from which is allowed to overlap with output. Must be at least blockSize() bytes in length.

See Also: decryptBlock(), blockSize()

Implemented in Speck, and AESCommon.

size_t BlockCipher::keySize ( ) const

pure virtual

Default size of the key for this block cipher, in bytes.

This value indicates the default, or recommended, size for the key.

See Also: setKey(), blockSize()

Implemented in AES256, AES192, AES128, and Speck.

bool BlockCipher::setKey	(	const uint8_t *	key,
		size_t	len
	)

pure virtual

Sets the key to use for future encryption and decryption operations.

Parameters

key	The key to use.
len	The length of the key.

Returns: Returns false if the key length is not supported, or the key is somehow "weak" and unusable by this cipher.

Use clear() or the destructor to remove the key and any other sensitive data from the object once encryption or decryption is complete.

See Also: keySize(), clear()

Implemented in AES256, AES192, AES128, and Speck.

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation