QCA::Cipher Class Reference

#include <QtCrypto>

Inheritance diagram for QCA::Cipher:

Public Types
enum	Mode {   CBC , CFB , ECB , OFB ,   CTR , GCM , CCM }
enum	Padding { DefaultPadding , NoPadding , PKCS7 }

Public Member Functions
	Cipher (const Cipher &from)
	Cipher (const QString &type, Mode mode, Padding pad, Direction dir, const SymmetricKey &key, const InitializationVector &iv, const AuthTag &tag, const QString &provider=QString())
	Cipher (const QString &type, Mode mode, Padding pad=DefaultPadding, Direction dir=Encode, const SymmetricKey &key=SymmetricKey(), const InitializationVector &iv=InitializationVector(), const QString &provider=QString())
int	blockSize () const
void	clear () override
Direction	direction () const
MemoryRegion	final () override
KeyLength	keyLength () const
Mode	mode () const
bool	ok () const override
Cipher &	operator= (const Cipher &from)
Padding	padding () const
void	setup (Direction dir, const SymmetricKey &key, const InitializationVector &iv, const AuthTag &tag)
void	setup (Direction dir, const SymmetricKey &key, const InitializationVector &iv=InitializationVector())
AuthTag	tag () const
QString	type () const
MemoryRegion	update (const MemoryRegion &a) override
bool	validKeyLength (int n) const
Public Member Functions inherited from QCA::Algorithm
	Algorithm (const Algorithm &from)
void	change (const QString &type, const QString &provider)
void	change (Provider::Context *c)
Provider::Context *	context ()
const Provider::Context *	context () const
Algorithm &	operator= (const Algorithm &from)
Provider *	provider () const
Provider::Context *	takeContext ()
QString	type () const
Public Member Functions inherited from QCA::Filter
MemoryRegion	process (const MemoryRegion &a)

Static Public Member Functions
static QStringList	supportedTypes (const QString &provider=QString())
static QString	withAlgorithms (const QString &cipherType, Mode modeType, Padding paddingType)

Additional Inherited Members
Protected Member Functions inherited from QCA::Algorithm
	Algorithm ()
	Algorithm (const QString &type, const QString &provider)

Detailed Description

General class for cipher (encryption / decryption) algorithms.

Cipher is the class for the various algorithms that perform low level encryption and decryption within QCA.

AES128, AES192 and AES256 are recommended for new applications.

Standard names for ciphers are:

• Blowfish - "blowfish"
• TripleDES - "tripledes"
• DES - "des"
• AES128 - "aes128"
• AES192 - "aes192"
• AES256 - "aes256"
• CAST5 (CAST-128) - "cast5"

When checking for the availability of a particular kind of cipher operation (e.g. AES128 in CBC mode with PKCS7 padding), you append the mode and padding type (in that example "aes128-cbc-pkcs7"). CFB and OFB modes don't use padding, so they are always just the cipher name followed by the mode (e.g. "blowfish-cfb" or "aes192-ofb"). If you are not using padding with CBC mode (i.e. you are ensuring block size operations yourself), just use the cipher name followed by "-cbc" (e.g. "blowfish-cbc" or "aes256-cbc").

Examples

aes-cmac.cpp, and ciphertest.cpp.

Definition at line 581 of file qca_basic.h.

Member Enumeration Documentation

Mode

enum QCA::Cipher::Mode

Mode settings for cipher algorithms.

Note

ECB is almost never what you want, unless you are trying to implement a Cipher variation that is not supported by QCA.

Enumerator
CBC	operate in Cipher Block Chaining mode
CFB	operate in Cipher FeedBack mode
ECB	operate in Electronic Code Book mode
OFB	operate in Output FeedBack Mode
CTR	operate in CounTer Mode
GCM	operate in Galois Counter Mode
CCM	operate in Counter with CBC-MAC

Definition at line 591 of file qca_basic.h.

Padding

enum QCA::Cipher::Padding

Padding variations for cipher algorithms.

See the Padding description for more details on padding schemes.

Enumerator
DefaultPadding	Default for cipher-mode.
NoPadding	Do not use padding.
PKCS7	Pad using the scheme in PKCS#7.

Definition at line 608 of file qca_basic.h.

Constructor & Destructor Documentation

Cipher() [1/3]

QCA::Cipher::Cipher	(	const QString &	type,
		Mode	mode,
		Padding	pad = DefaultPadding,
		Direction	dir = Encode,
		const SymmetricKey &	key = SymmetricKey(),
		const InitializationVector &	iv = InitializationVector(),
		const QString &	provider = QString() )

Standard constructor.

Parameters

type	the name of the cipher specialisation to use (e.g. "aes128")
mode	the operating Mode to use (e.g. QCA::Cipher::CBC)
pad	the type of Padding to use
dir	the Direction that this Cipher should use (Encode for encryption, Decode for decryption)
key	the SymmetricKey array that is the key
iv	the InitializationVector to use (not used for ECB mode)
provider	the name of the Provider to use

Note

Padding only applies to CBC and ECB modes. CFB and OFB ciphertext is always the length of the plaintext.

Cipher() [2/3]

QCA::Cipher::Cipher	(	const QString &	type,
		Mode	mode,
		Padding	pad,
		Direction	dir,
		const SymmetricKey &	key,
		const InitializationVector &	iv,
		const AuthTag &	tag,
		const QString &	provider = QString() )

Standard constructor.

Parameters

type	the name of the cipher specialisation to use (e.g. "aes128")
mode	the operating Mode to use (e.g. QCA::Cipher::CBC)
pad	the type of Padding to use
dir	the Direction that this Cipher should use (Encode for encryption, Decode for decryption)
key	the SymmetricKey array that is the key
iv	the InitializationVector to use (not used for ECB mode)
tag	the AuthTag to use (only for GCM and CCM modes)
provider	the name of the Provider to use

Note

Padding only applies to CBC and ECB modes. CFB and OFB ciphertext is always the length of the plaintext.

Cipher() [3/3]

QCA::Cipher::Cipher

(

const Cipher &

from

)

Standard copy constructor.

Parameters

from	the Cipher to copy state from

Member Function Documentation

blockSize()

int QCA::Cipher::blockSize

(

)

const

return the block size for the cipher object

clear()

void QCA::Cipher::clear ( )

overridevirtual

reset the cipher object, to allow re-use

Implements QCA::Filter.

direction()

Direction QCA::Cipher::direction

(

)

const

Return the cipher direction.

final()

MemoryRegion QCA::Cipher::final ( )

overridevirtual

complete the block of data, padding as required, and returning the completed block

Implements QCA::Filter.

Examples

ciphertest.cpp.

keyLength()

KeyLength QCA::Cipher::keyLength

(

)

const

Return acceptable key lengths.

mode()

Mode QCA::Cipher::mode

(

)

const

Return the cipher mode.

ok()

bool QCA::Cipher::ok ( ) const

overridevirtual

Test if an update() or final() call succeeded.

Returns

true if the previous call succeeded

Implements QCA::Filter.

Examples

ciphertest.cpp.

operator=()

Cipher & QCA::Cipher::operator=

(

const Cipher &

from

)

Assignment operator.

Parameters

from	the Cipher to copy state from

padding()

Padding QCA::Cipher::padding

(

)

const

Return the cipher padding type.

setup() [1/2]

void QCA::Cipher::setup	(	Direction	dir,
		const SymmetricKey &	key,
		const InitializationVector &	iv,
		const AuthTag &	tag )

Reset / reconfigure the Cipher.

You can use this to re-use an existing Cipher, rather than creating a new object with a slightly different configuration.

Parameters

dir	the Direction that this Cipher should use (Encode for encryption, Decode for decryption)
key	the SymmetricKey array that is the key
iv	the InitializationVector to use (not used for ECB Mode)
tag	the AuthTag to use (only for GCM and CCM modes)

Note

You should not leave iv empty for any Mode except ECB.

setup() [2/2]

void QCA::Cipher::setup	(	Direction	dir,
		const SymmetricKey &	key,
		const InitializationVector &	iv = InitializationVector() )

Reset / reconfigure the Cipher.

You can use this to re-use an existing Cipher, rather than creating a new object with a slightly different configuration.

Parameters

dir	the Direction that this Cipher should use (Encode for encryption, Decode for decryption)
key	the SymmetricKey array that is the key
iv	the InitializationVector to use (not used for ECB Mode)

Note

You should not leave iv empty for any Mode except ECB.

Examples

ciphertest.cpp.

supportedTypes()

static QStringList QCA::Cipher::supportedTypes ( const QString & provider = QString() )

static

Returns a list of all of the cipher types available.

Parameters

provider

the name of the provider to get a list from, if one provider is required. If not specified, available cipher types from all providers will be returned.

tag()

AuthTag QCA::Cipher::tag

(

)

const

return the authentication tag for the cipher object

type()

QString QCA::Cipher::type

(

)

const

Return the cipher type.

update()

MemoryRegion QCA::Cipher::update ( const MemoryRegion & a )

overridevirtual

pass in a byte array of data, which will be encrypted or decrypted (according to the Direction that was set in the constructor or in setup() ) and returned.

Parameters

a	the array of data to encrypt / decrypt

Implements QCA::Filter.

Examples

ciphertest.cpp.

validKeyLength()

bool QCA::Cipher::validKeyLength

(

int

n

)

const

Test if a key length is valid for the cipher algorithm.

Parameters

n	the key length in bytes

Returns

true if the key would be valid for the current algorithm

withAlgorithms()

static QString QCA::Cipher::withAlgorithms ( const QString & cipherType, Mode modeType, Padding paddingType )

static

Construct a Cipher type string.

Parameters

cipherType	the name of the algorithm (eg AES128, DES)
modeType	the mode to operate the cipher in (eg QCA::CBC, QCA::CFB)
paddingType	the padding required (eg QCA::NoPadding, QCA::PCKS7)

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

• qca_basic.h