Speck Class Reference

Speck block cipher with a 128-bit block size. More...

#include <Speck.h>

Inheritance diagram for Speck:

Public Member Functions
	Speck ()
	Constructs a Speck block cipher with no initial key. More...
size_t	blockSize () const
	Size of a single block processed by this cipher, in bytes. More...
size_t	keySize () const
	Default size of the key for this block cipher, in bytes. More...
bool	setKey (const uint8_t *key, size_t len)
	Sets the key to use for future encryption and decryption operations. More...
void	encryptBlock (uint8_t *output, const uint8_t *input)
	Encrypts a single block using this cipher. More...
void	decryptBlock (uint8_t *output, const uint8_t *input)
	Decrypts a single block using this cipher. More...
void	clear ()
	Clears all security-sensitive state from this block cipher. More...
Public Member Functions inherited from BlockCipher
	BlockCipher ()
	Constructs a block cipher.
virtual	~BlockCipher ()
	Destroys this block cipher object. More...

Detailed Description

Speck block cipher with a 128-bit block size.

Speck is a family of lightweight block ciphers designed by the National Security Agency (NSA). The ciphers are highly optimized for software implementation on microcontrollers.

This class implements the Speck family that uses 128-bit block sizes with 128-bit, 192-bit, or 256-bit key sizes. Other Speck families support smaller block sizes of 32, 48, 64, or 96 bits but such block sizes are too small for use in modern cryptosystems.

Note

Current crytoanalysis (up until 2015) has not revealed any obvious weaknesses in the full-round version of Speck. But if you are wary of ciphers designed by the NSA, then use ChaCha or AES instead.

The SpeckTiny and SpeckSmall classes provide alternative implementations that have reduced RAM and flash size requirements at the cost of some features and performance.

References: https://en.wikipedia.org/wiki/Speck_%28cipher%29, http://eprint.iacr.org/2013/404

See also

SpeckTiny, SpeckSmall

Definition at line 28 of file Speck.h.

Constructor & Destructor Documentation

Speck()

Speck::Speck

(

)

Constructs a Speck block cipher with no initial key.

This constructor must be followed by a call to setKey() before the block cipher can be used for encryption or decryption.

Definition at line 72 of file Speck.cpp.

Member Function Documentation

blockSize()

size_t Speck::blockSize ( ) const

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()

Implements BlockCipher.

Definition at line 82 of file Speck.cpp.

clear()

void Speck::clear ( )

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()

Implements BlockCipher.

Definition at line 550 of file Speck.cpp.

decryptBlock()

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

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()

Implements BlockCipher.

Definition at line 425 of file Speck.cpp.

encryptBlock()

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

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()

Implements BlockCipher.

Definition at line 303 of file Speck.cpp.

keySize()

size_t Speck::keySize ( ) const

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()

Implements BlockCipher.

Definition at line 87 of file Speck.cpp.

setKey()

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

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()

Implements BlockCipher.

Definition at line 105 of file Speck.cpp.

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

• Speck.h
• Speck.cpp