KDE 4.2 API Reference qca
QCA::Cipher Class Reference
[QCA user API]
#include <QtCrypto>
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").
Definition at line 575 of file qca_basic.h.
Public Types | |
| enum | Mode { CBC, CFB, ECB, OFB } |
| enum | Padding { DefaultPadding, NoPadding, PKCS7 } |
Public Member Functions | |
| int | blockSize () const |
| Cipher (const Cipher &from) | |
| Cipher (const QString &type, Mode mode, Padding pad=DefaultPadding, Direction dir=Encode, const SymmetricKey &key=SymmetricKey(), const InitializationVector &iv=InitializationVector(), const QString &provider=QString()) | |
| virtual void | clear () |
| Direction | direction () const |
| virtual MemoryRegion | final () |
| KeyLength | keyLength () const |
| Mode | mode () const |
| virtual bool | ok () const |
| Cipher & | operator= (const Cipher &from) |
| Padding | padding () const |
| void | setup (Direction dir, const SymmetricKey &key, const InitializationVector &iv=InitializationVector()) |
| QString | type () const |
| virtual MemoryRegion | update (const MemoryRegion &a) |
| bool | validKeyLength (int n) const |
| ~Cipher () | |
Static Public Member Functions | |
| static QStringList | supportedTypes (const QString &provider=QString()) |
| static QString | withAlgorithms (const QString &cipherType, Mode modeType, Padding paddingType) |
Member Enumeration Documentation
| 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
Definition at line 585 of file qca_basic.h.
| 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 599 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:
-
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.
Definition at line 269 of file qca_basic.cpp.
| QCA::Cipher::Cipher | ( | const Cipher & | from | ) |
Standard copy constructor.
- Parameters:
-
from the Cipher to copy state from
Definition at line 283 of file qca_basic.cpp.
| QCA::Cipher::~Cipher | ( | ) |
Definition at line 289 of file qca_basic.cpp.
Member Function Documentation
| int QCA::Cipher::blockSize | ( | ) | const |
| void QCA::Cipher::clear | ( | ) | [virtual] |
reset the cipher object, to allow re-use
Implements QCA::Filter.
Definition at line 342 of file qca_basic.cpp.
| Direction QCA::Cipher::direction | ( | ) | const |
| MemoryRegion QCA::Cipher::final | ( | ) | [virtual] |
complete the block of data, padding as required, and returning the completed block
Implements QCA::Filter.
Definition at line 357 of file qca_basic.cpp.
| KeyLength QCA::Cipher::keyLength | ( | ) | const |
| Cipher::Mode QCA::Cipher::mode | ( | ) | const |
| bool QCA::Cipher::ok | ( | ) | const [virtual] |
Test if an update() or final() call succeeded.
- Returns:
- true if the previous call succeeded
Implements QCA::Filter.
Definition at line 367 of file qca_basic.cpp.
Assignment operator.
- Parameters:
-
from the Cipher to copy state from
Definition at line 294 of file qca_basic.cpp.
| Cipher::Padding QCA::Cipher::padding | ( | ) | const |
| 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.
Definition at line 372 of file qca_basic.cpp.
| 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.
Definition at line 301 of file qca_basic.cpp.
| QString QCA::Cipher::type | ( | ) | const |
Return the cipher type.
Reimplemented from QCA::Algorithm.
Definition at line 306 of file qca_basic.cpp.
| MemoryRegion QCA::Cipher::update | ( | const MemoryRegion & | a | ) | [virtual] |
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.
Definition at line 348 of file qca_basic.cpp.
| 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
Definition at line 331 of file qca_basic.cpp.
| 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)
Definition at line 380 of file qca_basic.cpp.
The documentation for this class was generated from the following files:
