QCA::Cipher

#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 QString &type, Mode mode, Padding pad=DefaultPadding, Direction dir=Encode, const SymmetricKey &key=SymmetricKey(), const InitializationVector &iv=InitializationVector(), const QString &provider=QString())
 
 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 Cipher &from)
 
int blockSize () const
 
void clear () override
 
Direction direction () const
 
MemoryRegion final () override
 
KeyLength keyLength () const
 
Mode mode () const
 
bool ok () const override
 
Cipheroperator= (const Cipher &from)
 
Padding padding () const
 
void setup (Direction dir, const SymmetricKey &key, const InitializationVector &iv=InitializationVector())
 
void setup (Direction dir, const SymmetricKey &key, const InitializationVector &iv, const AuthTag &tag)
 
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 (Provider::Context *c)
 
void change (const QString &type, const QString &provider)
 
Provider::Contextcontext ()
 
const Provider::Contextcontext () const
 
Algorithmoperator= (const Algorithm &from)
 
Providerprovider () const
 
Provider::ContexttakeContext ()
 
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 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 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

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
typethe name of the cipher specialisation to use (e.g. "aes128")
modethe operating Mode to use (e.g. QCA::Cipher::CBC)
padthe type of Padding to use
dirthe Direction that this Cipher should use (Encode for encryption, Decode for decryption)
keythe SymmetricKey array that is the key
ivthe InitializationVector to use (not used for ECB mode)
providerthe 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.
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
typethe name of the cipher specialisation to use (e.g. "aes128")
modethe operating Mode to use (e.g. QCA::Cipher::CBC)
padthe type of Padding to use
dirthe Direction that this Cipher should use (Encode for encryption, Decode for decryption)
keythe SymmetricKey array that is the key
ivthe InitializationVector to use (not used for ECB mode)
tagthe AuthTag to use (only for GCM and CCM modes)
providerthe 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.
QCA::Cipher::Cipher ( const Cipher from)

Standard copy constructor.

Parameters
fromthe Cipher to copy state from

Member Function Documentation

int QCA::Cipher::blockSize ( ) const

return the block size for the cipher object

void QCA::Cipher::clear ( )
overridevirtual

reset the cipher object, to allow re-use

Implements QCA::Filter.

Direction QCA::Cipher::direction ( ) const

Return the cipher direction.

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 QCA::Cipher::keyLength ( ) const

Return acceptable key lengths.

Mode QCA::Cipher::mode ( ) const

Return the cipher mode.

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.
Cipher& QCA::Cipher::operator= ( const Cipher from)

Assignment operator.

Parameters
fromthe Cipher to copy state from
Padding QCA::Cipher::padding ( ) const

Return the cipher padding type.

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
dirthe Direction that this Cipher should use (Encode for encryption, Decode for decryption)
keythe SymmetricKey array that is the key
ivthe InitializationVector to use (not used for ECB Mode)
Note
You should not leave iv empty for any Mode except ECB.
Examples:
ciphertest.cpp.
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
dirthe Direction that this Cipher should use (Encode for encryption, Decode for decryption)
keythe SymmetricKey array that is the key
ivthe InitializationVector to use (not used for ECB Mode)
tagthe AuthTag to use (only for GCM and CCM modes)
Note
You should not leave iv empty for any Mode except ECB.
static QStringList QCA::Cipher::supportedTypes ( const QString provider = QString())
static

Returns a list of all of the cipher types available.

Parameters
providerthe 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.
AuthTag QCA::Cipher::tag ( ) const

return the authentication tag for the cipher object

QString QCA::Cipher::type ( ) const

Return the cipher type.

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
athe array of data to encrypt / decrypt

Implements QCA::Filter.

Examples:
ciphertest.cpp.
bool QCA::Cipher::validKeyLength ( int  n) const

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

Parameters
nthe key length in bytes
Returns
true if the key would be valid for the current algorithm
static QString QCA::Cipher::withAlgorithms ( const QString cipherType,
Mode  modeType,
Padding  paddingType 
)
static

Construct a Cipher type string.

Parameters
cipherTypethe name of the algorithm (eg AES128, DES)
modeTypethe mode to operate the cipher in (eg QCA::CBC, QCA::CFB)
paddingTypethe padding required (eg QCA::NoPadding, QCA::PCKS7)

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