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QMessageAuthenticationCode 类

QMessageAuthenticationCode 类提供生成基于哈希的消息身份验证代码的办法。 更多...

头： #include <QMessageAuthenticationCode>
CMake: find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake: QT += core

注意： 此类的所有函数 可重入 .

公共函数

QMessageAuthenticationCode (QCryptographicHash::Algorithm method , QByteArrayView key = {})
(从 6.6 起) QMessageAuthenticationCode (QMessageAuthenticationCode && other )
~QMessageAuthenticationCode ()
void addData (QByteArrayView data )
void addData (const char * data , qsizetype length )
bool addData (QIODevice * device )
void reset ()
QByteArray result () const
(从 6.6 起) QByteArrayView resultView () const
void setKey (QByteArrayView key )
(从 6.6 起) void swap (QMessageAuthenticationCode & other )
(从 6.6 起) QMessageAuthenticationCode & operator= (QMessageAuthenticationCode && other )

静态公共成员

QByteArray hash (QByteArrayView message , QByteArrayView key , QCryptographicHash::Algorithm method )

详细描述

Use the QMessageAuthenticationCode class to generate hash-based message authentication codes (HMACs). The class supports all cryptographic hash algorithms from QCryptographicHash (see also QCryptographicHash::Algorithm ).

To generate a message authentication code, pass a suitable hash algorithm and secret key to the constructor. Then process the message data by calling addData () one or more times. After the full message has been processed, get the final authentication code via the result () 函数： 

    QByteArray key = "key";
    QByteArray message = "The quick brown fox jumps over the lazy dog";
    ...
    QMessageAuthenticationCode code(QCryptographicHash::Sha256, key);
    code.addData(message);
    code.result().toHex(); // returns "f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8"

For simple cases like above, you can also use the static hash () 函数： 

    QMessageAuthenticationCode::hash(message, key, QCryptographicHash::Sha256).toHex();

注意： The cryptographic strength of the HMAC depends upon the size of the secret key, and the security of the underlying hash function.

另请参阅 QCryptographicHash and QCryptographicHash::Algorithm .

成员函数文档编制

[explicit] QMessageAuthenticationCode:: QMessageAuthenticationCode ( QCryptographicHash::Algorithm method , QByteArrayView key = {})

Constructs an object that can be used to create a cryptographic hash from data using method method and key key .

注意： In Qt versions prior to 6.6, this function took its arguments as QByteArray , not QByteArrayView . If you experience compile errors, it's because your code is passing objects that are implicitly convertible to QByteArray , but not QByteArrayView . Wrap the corresponding argument in QByteArray{~~~} to make the cast explicit. This is backwards-compatible with old Qt versions.

[noexcept, since 6.6] QMessageAuthenticationCode:: QMessageAuthenticationCode ( QMessageAuthenticationCode && other )

Move-constructs a new QMessageAuthenticationCode from other .

注意： The moved-from object other is placed in a partially-formed state, in which the only valid operations are destruction and assignment of a new object.

该函数在 Qt 6.6 引入。

[noexcept] QMessageAuthenticationCode:: ~QMessageAuthenticationCode ()

销毁对象。

[noexcept] void QMessageAuthenticationCode:: addData ( QByteArrayView data )

添加 data to the message.

注意： In Qt versions prior to 6.6, this function took its arguments as QByteArray , not QByteArrayView . If you experience compile errors, it's because your code is passing objects that are implicitly convertible to QByteArray , but not QByteArrayView . Wrap the corresponding argument in QByteArray{~~~} to make the cast explicit. This is backwards-compatible with old Qt versions.

另请参阅 resultView () 和 result ().

void QMessageAuthenticationCode:: addData (const char * data , qsizetype length )

这是重载函数。

Adds the first length chars of data to the message.

bool QMessageAuthenticationCode:: addData ( QIODevice * device )

读取数据，从打开 QIODevice device until it ends and adds it to message. Returns true 若读取是成功的。

注意： device must be already opened.

[static] QByteArray QMessageAuthenticationCode:: hash ( QByteArrayView message , QByteArrayView key , QCryptographicHash::Algorithm method )

Returns the authentication code for the message message using the key key and the method method .

注意： In Qt versions prior to 6.6, this function took its arguments as QByteArray , not QByteArrayView . If you experience compile errors, it's because your code is passing objects that are implicitly convertible to QByteArray , but not QByteArrayView . Wrap the corresponding argument in QByteArray{~~~} to make the cast explicit. This is backwards-compatible with old Qt versions.

[noexcept] void QMessageAuthenticationCode:: reset ()

Resets message data. Calling this function doesn't affect the key.

QByteArray QMessageAuthenticationCode:: result () const

Returns the final authentication code.

另请参阅 resultView () 和 QByteArray::toHex ().

[noexcept, since 6.6] QByteArrayView QMessageAuthenticationCode:: resultView () const

返回最终的哈希值。

Note that the returned view remains valid only as long as the QMessageAuthenticationCode object is not modified by other means.

该函数在 Qt 6.6 引入。

另请参阅 result ().

[noexcept] void QMessageAuthenticationCode:: setKey ( QByteArrayView key )

Sets secret key . Calling this function automatically resets the object state.

For optimal performance, call this function only to change the active key, not to set an initial key, as in 

QMessageAuthenticationCode mac(method);
mac.setKey(key); // does extra work
use(mac);

Prefer to pass initial keys as the constructor argument: 

QMessageAuthenticationCode mac(method, key); // OK, optimal
use(mac);

You can use std::optional to delay construction of a QMessageAuthenticationCode until you know the key: 

std::optional<QMessageAuthenticationCode> mac;
~~~
key = ~~~;
mac.emplace(method, key);
use(*mac);

注意： In Qt versions prior to 6.6, this function took its arguments as QByteArray , not QByteArrayView . If you experience compile errors, it's because your code is passing objects that are implicitly convertible to QByteArray , but not QByteArrayView . Wrap the corresponding argument in QByteArray{~~~} to make the cast explicit. This is backwards-compatible with old Qt versions.

[noexcept, since 6.6] void QMessageAuthenticationCode:: swap ( QMessageAuthenticationCode & other )

Swaps message authentication code other with this message authentication code. This operation is very fast and never fails.

该函数在 Qt 6.6 引入。

[noexcept, since 6.6] QMessageAuthenticationCode &QMessageAuthenticationCode:: operator= ( QMessageAuthenticationCode && other )

移动赋值 other 到此 QMessageAuthenticationCode 实例。

注意： The moved-from object other is placed in a partially-formed state, in which the only valid operations are destruction and assignment of a new object.

该函数在 Qt 6.6 引入。

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