mirror of
https://github.com/QuasarApp/Qt-AES.git
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0ddf76d59a
* Pass expKey parameter of addRoundKey() by const reference to avoid unnecessary copy. * Use C++11 nullptr instead of NULL, make it clear that default value of iv parameter in encode() and decode() is empty QByteArray instead of implicit conversion from null pointer via QByteArray(const char *, int = -1) constructor. * Change parameter names in declarations of cipher(), invCipher() and byteXor() to match definitions. * Convert AES-NI-related files to headers, place functions with internal linkage to anonymous namespace to avoid exporting them, don't use inline specifier (inline keyword have different meaning in C++ rather than in C). * Use char literals instead of implementation-defined int-to-signed-char conversions where possible. * Set default value for padding argument in static RemovePadding() to match sample in README.
136 lines
4.3 KiB
Markdown
136 lines
4.3 KiB
Markdown
# Qt-AES
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Small and portable AES encryption class for Qt.
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Native support for all key sizes - 128/192/256 bits - ECB, CBC, CFB and OFB modes
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AES-NI support for all key sizes - ECB, CBC modes
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## Usage
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### Available Methods
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```
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// Encode of rawText with key
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// iv is used in CBC mode
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// return the encrypted byte array
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QByteArray encode(const QByteArray rawText, const QByteArray key, const QByteArray iv = QByteArray());
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// Decode of rawText with key
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// iv is used in CBC mode
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// return the decrypted byte array
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QByteArray decode(const QByteArray rawText, const QByteArray key, const QByteArray iv = QByteArray());
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// Key expansion in Rijndael schedule
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// return the new expanded key as byte array
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QByteArray expandKey(const QByteArray key);
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```
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The same methods are available as static calls
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```
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QAESEncryption::Crypt => encode(...)
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QAESEncryption::Decrypt => decode(...)
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QAESEncryption::ExpandKey => expandKey(...)
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```
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#### AES Levels
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The class supports all AES key lenghts
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* AES_128
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* AES_192
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* AES_256
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#### Modes
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The class supports the following operating modes
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* ECB
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* CBC
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* CFB
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* OFB
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#### Padding
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By default the padding method is `ISO`, however, the class supports:
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* ZERO
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* PKCS7
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* ISO
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### Example
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Sample code using a 128bit key in ECB mode
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```
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#include "qaesencryption.h"
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QAESEncryption encryption(QAESEncryption::AES_128, QAESEncryption::ECB);
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QByteArray encodedText = encryption.encode(plainText, key);
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QByteArray decodedText = encryption.decode(encodedText, key);
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```
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Example for 256bit CBC using QString
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```
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#include <QCryptographicHash>
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#include "qaesencryption.h"
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QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::CBC);
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QString inputStr("The Advanced Encryption Standard (AES), also known by its original name Rijndael "
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"is a specification for the encryption of electronic data established by the U.S. "
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"National Institute of Standards and Technology (NIST) in 2001");
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QString key("your-string-key");
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QString iv("your-IV-vector");
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QByteArray hashKey = QCryptographicHash::hash(key.toLocal8Bit(), QCryptographicHash::Sha256);
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QByteArray hashIV = QCryptographicHash::hash(iv.toLocal8Bit(), QCryptographicHash::Md5);
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QByteArray encodeText = encryption.encode(inputStr.toLocal8Bit(), hashKey, hashIV);
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QByteArray decodeText = encryption.decode(encodeText, hashKey, hashIV);
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QString decodedString = QString(encryption.removePadding(decodeText));
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//decodedString == inputStr !!
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```
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### Example via static invocation
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Static invocation without creating instances, 256 bit key, ECB mode, starting from *QString* text/key
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```
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#include <QCryptographicHash>
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#include "qaesencryption.h"
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QString inputStr("The Advanced Encryption Standard (AES), also known by its original name Rijndael "
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"is a specification for the encryption of electronic data established by the U.S. "
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"National Institute of Standards and Technology (NIST) in 2001");
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QString key("your-string-key");
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QString iv("your-IV-vector");
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QByteArray hashKey = QCryptographicHash::hash(key.toLocal8Bit(), QCryptographicHash::Sha256);
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QByteArray hashIV = QCryptographicHash::hash(iv.toLocal8Bit(), QCryptographicHash::Md5);
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//Static invocation
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QByteArray encrypted = QAESEncryption::Crypt(QAESEncryption::AES_256, QAESEncryption::CBC,
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inputStr.toLocal8Bit(), hashKey, hashIV);
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//...
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// Removal of Padding via Static function
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QString decodedString = QString(QAESEncryption::RemovePadding(decodeText));
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```
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## AES New Instructions Set
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To use the hardware acceleration provided by the AES New Instructions Set, define USE_INTEL_AES_IF_AVAILABLE
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If the CPU supports it, the code will switch to use AESNI automatically.
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The feature is enabled by default
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## Unit Testing
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The unit testing vectors used are included in [NIST-Recommendation for Block Cipher Modes of Operation](http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38a.pdf)
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Please note that this code is not audited or AES-certified by any competent authority, use it at your own risk.
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## Dependencies
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* qtcore
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No OpenSSL required.
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## Contact
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Question or suggestions are welcome!
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Please use the GitHub issue tracking to report suggestions or issues.
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## License
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This software is provided under the [UNLICENSE](http://unlicense.org/)
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## Known Issues
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Please take a look at the list of currently open issues
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