Secure Sockets Layer (SSL) Classes
The classes below provide support for secure network communication using the Secure Sockets Layer (SSL) protocol, using the OpenSSL Toolkit to perform encryption and protocol handling.
From Qt version 5.15 onwards, the officially supported version for OpenSSL is 1.1.1 or later.
Qt version 5.15.1 onward is also compatible with OpenSSL 3.
This class provides encryption for UDP sockets
This class implements server-side DTLS cookie generation and verification
This class defines parameters for DTLS cookie generator
This class represents Online Certificate Status Protocol response
Declares enums common to all SSL classes in Qt Network
Convenient API for an X509 certificate
API for accessing the extensions of an X509 certificate
Represents an SSL cryptographic cipher
Holds the configuration and state of an SSL connection
Interface for Diffie-Hellman parameters for servers
Represents an elliptic curve for use by elliptic-curve cipher algorithms
Interface for private and public keys
Authentication data for pre shared keys (PSK) ciphersuites
SSL encrypted socket for both clients and servers
Describes the current state of DTLS handshake
Describes errors that can be found by QDtls and QDtlsClientVerifier
Describes the Online Certificate Status
Describes the reason for revocation
When building Qt from source, the configuration system checks for the presence of the
openssl/opensslv.h header provided by source or developer packages of OpenSSL.
By default, an SSL-enabled Qt library dynamically loads any installed OpenSSL library at run-time. However, it is possible to link against the library at compile-time by configuring Qt with the
When building a version of Qt linked against OpenSSL, the build system will attempt to link with libssl and libcrypt libraries located in the default location on the developer's system. This location is configurable: set the
OPENSSL_LIBS environment variable to contain the linker options required to link Qt against the installed library. For example, on a Unix/Linux system:
OPENSSL_LIBS='-L/opt/ssl/lib -lssl -lcrypto' ./configure -openssl-linked
To disable SSL support in a Qt build, configure Qt with the
Datagram Transport Layer Security (DTLS) is a protocol that enables security for datagram-based applications, providing them with protection against eavesdropping, tampering, or message forgery. The DTLS protocol is based on the stream-oriented Transport Layer Security (TLS) protocol. QtNetwork enables the use of DTLS with User Datagram Protocol (UDP), as defined by RFC 6347.
Qt binary installers include the OpenSSL libraries used by QtNetwork. However, those are not automatically deployed with applications that are built with Qt. Import and export restrictions apply for some types of software, and for some parts of the world. Developers wishing to use SSL communication in their deployed applications should either ensure that their users have the appropriate libraries installed, or they should consult a suitably qualified legal professional to ensure that applications using code from the OpenSSL project are correctly certified for import and export in relevant regions of the world.
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