QPasswordDigestor Namespace Reference

\inmodule QtNetwork More...

Functions
Q_NETWORK_EXPORT QByteArray	deriveKeyPbkdf1 (QCryptographicHash::Algorithm algorithm, const QByteArray &data, const QByteArray &salt, int iterations, quint64 dkLen)
Q_NETWORK_EXPORT QByteArray	deriveKeyPbkdf2 (QCryptographicHash::Algorithm algorithm, const QByteArray &data, const QByteArray &salt, int iterations, quint64 dkLen)

Detailed Description

\inmodule QtNetwork

The QPasswordDigestor namespace contains functions which you can use to generate hashes or keys.

Function Documentation

deriveKeyPbkdf1()

Q_NETWORK_EXPORT QByteArray QPasswordDigestor::deriveKeyPbkdf1	(	QCryptographicHash::Algorithm	algorithm,
		const QByteArray &	data,
		const QByteArray &	salt,
		int	iterations,
		quint64	dkLen )

Since

5.12

Returns a hash computed using the PBKDF1-algorithm as defined in \l {RFC 8018, section 5.1}.

The function takes the data and salt, and then hashes it repeatedly for iterations iterations using the specified hash algorithm. If the resulting hash is longer than dkLen then it is truncated before it is returned.

This function only supports SHA-1 and MD5! The max output size is 160 bits (20 bytes) when using SHA-1, or 128 bits (16 bytes) when using MD5. Specifying a value for dkLen which is greater than this results in a warning and an empty QByteArray is returned. To programmatically check this limit you can use \l {QCryptographicHash::hashLength}. Furthermore: the salt must always be 8 bytes long!

Note

This function is provided for use with legacy applications and all new applications are recommended to use \l {deriveKeyPbkdf2} {PBKDF2}.

See also

deriveKeyPbkdf2, QCryptographicHash, QCryptographicHash::hashLength

Definition at line 58 of file qpassworddigestor.cpp.

deriveKeyPbkdf2()

Q_NETWORK_EXPORT QByteArray QPasswordDigestor::deriveKeyPbkdf2	(	QCryptographicHash::Algorithm	algorithm,
		const QByteArray &	data,
		const QByteArray &	salt,
		int	iterations,
		quint64	dkLen )

Since

5.12

Derive a key using the PBKDF2-algorithm as defined in \l {RFC 8018, section 5.2}.

This function takes the data and salt, and then applies HMAC-X, where the X is algorithm, repeatedly. It internally concatenates intermediate results to the final output until at least dkLen amount of bytes have been computed and it will execute HMAC-X iterations times each time a concatenation is required. The total number of times it will execute HMAC-X depends on iterations, dkLen and algorithm and can be calculated as {iterations * ceil(dkLen / QCryptographicHash::hashLength(algorithm))}.

See also

deriveKeyPbkdf1, QMessageAuthenticationCode, QCryptographicHash

Definition at line 195 of file qpassworddigestor.cpp.