SimpleKeyingInterface

SimpleKeyingInterface

Documentation

#include <cryptopp/cryptlib.h>

SimpleKeyingInterface is a class used by symmetric ciphers to provide functions for security parameters such as keys, initialization vectors and rounds.

Keying Functions

SimpleKeyingInterface provides the following functions for keying material.

Keying functions

Function	Comments
MinKeyLength	minimum key length, in bytes
MaxKeyLength	maximum key length, in bytes
DefaultKeyLength	default key length, in bytes
GetValidKeyLength	returns a valid key length, rounds up to the next valid length if needed
IsValidKeyLength	returns true if the key length is valid
SetKey	sets only the key for the algorithm
SetKeyWithRounds	sets the key and rounds for the algorithm
SetKeyWithIV	sets the key and iv for the algorithm

Nearly all ciphers simply use SetKeyWithIV. However, SetKey takes a NameValuePairs, so more security parameters can be set for an algorithm if needed.

SetKey (const byte *key, size_t length, const NameValuePairs &params = g_nullNameValuePairs)

IV Functions

SimpleKeyingInterface provides the following functions for initialization vectors.

IV functions

Function	Comments
IVRequirement	iv requirements, such as unique or random
IsResynchronizable	returns true if the algorithm uses an iv
CanUseRandomIVs	returns true if the algorithm can use a random iv
CanUsePredictableIVs	returns true if the algorithm can use a predictable iv
CanUseStructuredIVs	returns true if the algorithm can use a structured iv
IVSize	iv size, in bytes
DefaultIVLength	minimum iv length, in bytes
MaxIVLength	maximum iv length, in bytes
DefaultIVLength	default iv length, in bytes
Resynchronize	sets a new iv under a key for the algorithm
GetNextIV	returns an iv for the algorithm

IVRequirement returns the type of IV used by the algorithm as an IV_Requirement enumeration. The values are listed below.

IV_Requirement values

Value	Meaning
UNIQUE_IV	The IV must be unique.
RANDOM_IV	The IV must be random and possibly predictable.
UNPREDICTABLE_RANDOM_IV	The IV must be random and unpredictable.
INTERNALLY_GENERATED_IV	The IV is set by the object.
NOT_RESYNCHRONIZABLE	The object does not use an IV.