Simple encryption and decryption of strings and byte arrays. More...

#include <QxSimpleCrypt.h>

Public Types
enum	CompressionMode { CompressionAuto, CompressionAlways, CompressionNever }
enum	IntegrityProtectionMode { ProtectionNone, ProtectionChecksum, ProtectionHash }
enum	Error { ErrorNoError, ErrorNoKeySet, ErrorUnknownVersion, ErrorIntegrityFailed }
enum	CryptoFlag { CryptoFlagNone = 0, CryptoFlagCompression = 0x01, CryptoFlagChecksum = 0x02, CryptoFlagHash = 0x04 }
Public Member Functions
	QxSimpleCrypt ()
	QxSimpleCrypt (quint64 key)
void	setKey (quint64 key)
bool	hasKey () const
void	setCompressionMode (CompressionMode mode)
CompressionMode	compressionMode () const
void	setIntegrityProtectionMode (IntegrityProtectionMode mode)
IntegrityProtectionMode	integrityProtectionMode () const
Error	lastError () const
QString	encryptToString (const QString &plaintext)
QString	encryptToString (QByteArray plaintext)
QByteArray	encryptToByteArray (const QString &plaintext)
QByteArray	encryptToByteArray (QByteArray plaintext)
QString	decryptToString (const QString &cyphertext)
QByteArray	decryptToByteArray (const QString &cyphertext)
QString	decryptToString (QByteArray cypher)
QByteArray	decryptToByteArray (QByteArray cypher)
	Q_DECLARE_FLAGS (CryptoFlags, CryptoFlag)
Private Member Functions
void	splitKey ()
Private Attributes
quint64	m_key
QVector< char >	m_keyParts
CompressionMode	m_compressionMode
IntegrityProtectionMode	m_protectionMode
Error	m_lastError

Detailed Description

Simple encryption and decryption of strings and byte arrays.

This class provides a simple implementation of encryption and decryption of strings and byte arrays : http://qt-project.org/wiki/Simple_encryption

Warning:: The encryption provided by this class is NOT strong encryption. It may help to shield things from curious eyes, but it will NOT stand up to someone determined to break the encryption. Don't say you were not warned.

The class uses a 64 bit key. Simply create an instance of the class, set the key, and use the encryptToString() method to calculate an encrypted version of the input string. To decrypt that string again, use an instance of QxSimpleCrypt initialized with the same key, and call the decryptToString() method with the encrypted string. If the key matches, the decrypted version of the string will be returned again.

If you do not provide a key, or if something else is wrong, the encryption and decryption function will return an empty string or will return a string containing nonsense. lastError() will return a value indicating if the method was succesful, and if not, why not.

QxSimpleCrypt is prepared for the case that the encryption and decryption algorithm is changed in a later version, by prepending a version identifier to the cypertext.

Definition at line 73 of file QxSimpleCrypt.h.

Member Enumeration Documentation

enum qx::QxSimpleCrypt::CompressionMode

CompressionMode describes if compression will be applied to the data to be encrypted.

Enumerator:

CompressionAuto	Only apply compression if that results in a shorter plaintext.
CompressionAlways	Always apply compression. Note that for short inputs, a compression may result in longer data
CompressionNever	Never apply compression.

Definition at line 82 of file QxSimpleCrypt.h.

enum qx::QxSimpleCrypt::CryptoFlag

Enumerator:

CryptoFlagNone
CryptoFlagCompression
CryptoFlagChecksum
CryptoFlagHash

Definition at line 227 of file QxSimpleCrypt.h.

enum qx::QxSimpleCrypt::Error

Error describes the type of error that occured.

Enumerator:

ErrorNoError	No error occurred.
ErrorNoKeySet	No key was set. You can not encrypt or decrypt without a valid key.
ErrorUnknownVersion	The version of this data is unknown, or the data is otherwise not valid.
ErrorIntegrityFailed	The integrity check of the data failed. Perhaps the wrong key was used.

Definition at line 105 of file QxSimpleCrypt.h.

enum qx::QxSimpleCrypt::IntegrityProtectionMode

IntegrityProtectionMode describes measures taken to make it possible to detect problems with the data or wrong decryption keys.

Measures involve adding a checksum or a cryptograhpic hash to the data to be encrypted. This increases the length of the resulting cypertext, but makes it possible to check if the plaintext appears to be valid after decryption.

Enumerator:

ProtectionNone	The integerity of the encrypted data is not protected. It is not really possible to detect a wrong key, for instance.
ProtectionChecksum	A simple checksum is used to verify that the data is in order. If not, an empty string is returned.
ProtectionHash	A cryptographic hash is used to verify the integrity of the data. This method produces a much stronger, but longer check

Definition at line 96 of file QxSimpleCrypt.h.

Constructor & Destructor Documentation

qx::QxSimpleCrypt::QxSimpleCrypt ( )

Constructor.

Constructs a QxSimpleCrypt instance without a valid key set on it.

qx::QxSimpleCrypt::QxSimpleCrypt ( quint64 key ) [explicit]

Constructor.

Constructs a QxSimpleCrypt instance and initializes it with the given

key.

Member Function Documentation

CompressionMode qx::QxSimpleCrypt::compressionMode ( ) const [inline]

Returns the CompressionMode that is currently in use.

Definition at line 144 of file QxSimpleCrypt.h.

QByteArray qx::QxSimpleCrypt::decryptToByteArray ( const QString & cyphertext )

Decrypts a cyphertext string encrypted with this class with the set key back to the plain text version.

If an error occured, such as non-matching keys between encryption and decryption, an empty string or a string containing nonsense may be returned.

QByteArray qx::QxSimpleCrypt::decryptToByteArray ( QByteArray cypher )

Decrypts a cyphertext binary encrypted with this class with the set key back to the plain text version.

If an error occured, such as non-matching keys between encryption and decryption, an empty string or a string containing nonsense may be returned.

QString qx::QxSimpleCrypt::decryptToString ( const QString & cyphertext )

Decrypts a cyphertext string encrypted with this class with the set key back to the plain text version.

If an error occured, such as non-matching keys between encryption and decryption, an empty string or a string containing nonsense may be returned.

QString qx::QxSimpleCrypt::decryptToString ( QByteArray cypher )

Decrypts a cyphertext binary encrypted with this class with the set key back to the plain text version.

If an error occured, such as non-matching keys between encryption and decryption, an empty string or a string containing nonsense may be returned.

QByteArray qx::QxSimpleCrypt::encryptToByteArray ( const QString & plaintext )

Encrypts the

plaintext string with the key the class was initialized with, and returns a binary cyphertext in a QByteArray the result.

This method returns a byte array, that is useable for storing a binary format. If you need a string you can store in a text file, use encryptToString() instead.

QByteArray qx::QxSimpleCrypt::encryptToByteArray ( QByteArray plaintext )

Encrypts the

plaintext QByteArray with the key the class was initialized with, and returns a binary cyphertext in a QByteArray the result.

This method returns a byte array, that is useable for storing a binary format. If you need a string you can store in a text file, use encryptToString() instead.

QString qx::QxSimpleCrypt::encryptToString ( const QString & plaintext )

Encrypts the

plaintext string with the key the class was initialized with, and returns a cyphertext the result. The result is a base64 encoded version of the binary array that is the actual result of the string, so it can be stored easily in a text format.

QString qx::QxSimpleCrypt::encryptToString ( QByteArray plaintext )

Encrypts the

plaintext QByteArray with the key the class was initialized with, and returns a cyphertext the result. The result is a base64 encoded version of the binary array that is the actual result of the encryption, so it can be stored easily in a text format.

bool qx::QxSimpleCrypt::hasKey ( ) const [inline]

Returns true if QxSimpleCrypt has been initialized with a key.

Definition at line 132 of file QxSimpleCrypt.h.

IntegrityProtectionMode qx::QxSimpleCrypt::integrityProtectionMode ( ) const [inline]

Returns the IntegrityProtectionMode that is currently in use.

Definition at line 156 of file QxSimpleCrypt.h.

Error qx::QxSimpleCrypt::lastError ( ) const [inline]

Returns the last error that occurred.

Definition at line 161 of file QxSimpleCrypt.h.

qx::QxSimpleCrypt::Q_DECLARE_FLAGS	(	CryptoFlags	,
		CryptoFlag
	)

void qx::QxSimpleCrypt::setCompressionMode ( CompressionMode mode ) [inline]

Sets the compression mode to use when encrypting data. The default mode is Auto.

Note that decryption is not influenced by this mode, as the decryption recognizes what mode was used when encrypting.

Definition at line 140 of file QxSimpleCrypt.h.

void qx::QxSimpleCrypt::setIntegrityProtectionMode ( IntegrityProtectionMode mode ) [inline]

Sets the integrity mode to use when encrypting data. The default mode is Checksum.

Note that decryption is not influenced by this mode, as the decryption recognizes what mode was used when encrypting.

Definition at line 152 of file QxSimpleCrypt.h.

void qx::QxSimpleCrypt::setKey ( quint64 key )

(Re-) initializes the key with the given

key.

void qx::QxSimpleCrypt::splitKey ( ) [private]

Member Data Documentation

CompressionMode qx::QxSimpleCrypt::m_compressionMode [private]

Definition at line 240 of file QxSimpleCrypt.h.

quint64 qx::QxSimpleCrypt::m_key [private]

Definition at line 238 of file QxSimpleCrypt.h.

QVector<char> qx::QxSimpleCrypt::m_keyParts [private]

Definition at line 239 of file QxSimpleCrypt.h.

Error qx::QxSimpleCrypt::m_lastError [private]

Definition at line 242 of file QxSimpleCrypt.h.

IntegrityProtectionMode qx::QxSimpleCrypt::m_protectionMode [private]

Definition at line 241 of file QxSimpleCrypt.h.

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

C:/Dev/_Perso/QxOrm/include/QxCommon/QxSimpleCrypt.h

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation