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QSsl Namespace

The QSsl namespace declares enums common to all SSL classes in Qt Network. More...

Header: #include <QSsl>
CMake: find_package(Qt6 REQUIRED COMPONENTS Network)
target_link_libraries(mytarget PRIVATE Qt6::Network)
qmake: QT += network


enum class AlertLevel { Warning, Fatal, Unknown }
enum class AlertType { CloseNotify, UnexpectedMessage, BadRecordMac, RecordOverflow, DecompressionFailure, …, UnknownAlertMessage }
enum AlternativeNameEntryType { EmailEntry, DnsEntry, IpAddressEntry }
enum EncodingFormat { Pem, Der }
enum class ImplementedClass { Key, Certificate, Socket, DiffieHellman, EllipticCurve, …, DtlsCookie }
enum KeyAlgorithm { Rsa, Dsa, Ec, Dh, Opaque }
enum KeyType { PrivateKey, PublicKey }
enum SslOption { SslOptionDisableEmptyFragments, SslOptionDisableSessionTickets, SslOptionDisableCompression, SslOptionDisableServerNameIndication, SslOptionDisableLegacyRenegotiation, …, SslOptionDisableServerCipherPreference }
flags SslOptions
enum SslProtocol { TlsV1_0, TlsV1_0OrLater, TlsV1_1, TlsV1_1OrLater, TlsV1_2, …, SecureProtocols }
enum class SupportedFeature { CertificateVerification, ClientSideAlpn, ServerSideAlpn, Ocsp, Psk, …, Alerts }

Detailed Description

Type Documentation

[since 6.0] enum class AlertLevel

Describes the level of an alert message

This enum describes the level of an alert message that was sent or received.

Constant Value Description
QSslSocket::AlertLevel::Warning 0 Non-fatal alert message
QSslSocket::AlertLevel::Fatal 1 Fatal alert message, the underlying backend will handle such an alert properly and close the connection.
QSslSocket::AlertLevel::Unknown 2 An alert of unknown level of severity.

This enum was introduced or modified in Qt 6.0.

[since 6.0] enum class AlertType

Enumerates possible codes that an alert message can have

See RFC 8446, section 6 for the possible values and their meaning.

Constant Value Description
QSslSocket::AlertType::CloseNotify 0 ,
QSslSocket::AlertType::UnexpectedMessage 10  
QSslSocket::AlertType::BadRecordMac 20  
QSslSocket::AlertType::RecordOverflow 22  
QSslSocket::AlertType::DecompressionFailure 30  
QSslSocket::AlertType::HandshakeFailure 40  
QSslSocket::AlertType::NoCertificate 41  
QSslSocket::AlertType::BadCertificate 42  
QSslSocket::AlertType::UnsupportedCertificate 43  
QSslSocket::AlertType::CertificateRevoked 44  
QSslSocket::AlertType::CertificateExpired 45  
QSslSocket::AlertType::CertificateUnknown 46  
QSslSocket::AlertType::IllegalParameter 47  
QSslSocket::AlertType::UnknownCa 48  
QSslSocket::AlertType::AccessDenied 49  
QSslSocket::AlertType::DecodeError 50  
QSslSocket::AlertType::DecryptError 51  
QSslSocket::AlertType::ExportRestriction 60  
QSslSocket::AlertType::ProtocolVersion 70  
QSslSocket::AlertType::InsufficientSecurity 71  
QSslSocket::AlertType::InternalError 80  
QSslSocket::AlertType::InappropriateFallback 86  
QSslSocket::AlertType::UserCancelled 90  
QSslSocket::AlertType::NoRenegotiation 100  
QSslSocket::AlertType::MissingExtension 109  
QSslSocket::AlertType::UnsupportedExtension 110  
QSslSocket::AlertType::CertificateUnobtainable 111  
QSslSocket::AlertType::UnrecognizedName 112  
QSslSocket::AlertType::BadCertificateStatusResponse 113  
QSslSocket::AlertType::BadCertificateHashValue 114  
QSslSocket::AlertType::UnknownPskIdentity 115  
QSslSocket::AlertType::CertificateRequired 116  
QSslSocket::AlertType::NoApplicationProtocol 120  
QSslSocket::AlertType::UnknownAlertMessage 255  

This enum was introduced or modified in Qt 6.0.

enum QSsl::AlternativeNameEntryType

Describes the key types for alternative name entries in QSslCertificate.

Constant Value Description
QSsl::EmailEntry 0 An email entry; the entry contains an email address that the certificate is valid for.
QSsl::DnsEntry 1 A DNS host name entry; the entry contains a host name entry that the certificate is valid for. The entry may contain wildcards.
QSsl::IpAddressEntry 2 An IP address entry; the entry contains an IP address entry that the certificate is valid for, introduced in Qt 5.13.

See also QSslCertificate::subjectAlternativeNames().

enum QSsl::EncodingFormat

Describes supported encoding formats for certificates and keys.

Constant Value Description
QSsl::Pem 0 The PEM format.
QSsl::Der 1 The DER format.

[since 6.1] enum class ImplementedClass

Enumerates classes that a TLS backend implements

In QtNetwork, some classes have backend-specific implementation and thus can be left unimplemented. Enumerators in this enum indicate, which class has a working implementation in the backend.

Constant Value Description
QSslSocket::ImplementedClass::Key 0 Class QSslKey.
QSslSocket::ImplementedClass::Certificate 1 Class QSslCertificate.
QSslSocket::ImplementedClass::Socket 2 Class QSslSocket.
QSslSocket::ImplementedClass::DiffieHellman 3 Class QSslDiffieHellmanParameters.
QSslSocket::ImplementedClass::EllipticCurve 4 Class QSslEllipticCurve.
QSslSocket::ImplementedClass::Dtls 5 Class QDtls.
QSslSocket::ImplementedClass::DtlsCookie 6 Class QDtlsClientVerifier.

This enum was introduced or modified in Qt 6.1.

enum QSsl::KeyAlgorithm

Describes the different key algorithms supported by QSslKey.

Constant Value Description
QSsl::Rsa 1 The RSA algorithm.
QSsl::Dsa 2 The DSA algorithm.
QSsl::Ec 3 The Elliptic Curve algorithm.
QSsl::Dh 4 The Diffie-Hellman algorithm.
QSsl::Opaque 0 A key that should be treated as a 'black box' by QSslKey.

The opaque key facility allows applications to add support for facilities such as PKCS#11 that Qt does not currently offer natively.

enum QSsl::KeyType

Describes the two types of keys QSslKey supports.

Constant Value Description
QSsl::PrivateKey 0 A private key.
QSsl::PublicKey 1 A public key.

enum QSsl::SslOption
flags QSsl::SslOptions

Describes the options that can be used to control the details of SSL behaviour. These options are generally used to turn features off to work around buggy servers.

Constant Value Description
QSsl::SslOptionDisableEmptyFragments 0x01 Disables the insertion of empty fragments into the data when using block ciphers. When enabled, this prevents some attacks (such as the BEAST attack), however it is incompatible with some servers.
QSsl::SslOptionDisableSessionTickets 0x02 Disables the SSL session ticket extension. This can cause slower connection setup, however some servers are not compatible with the extension.
QSsl::SslOptionDisableCompression 0x04 Disables the SSL compression extension. When enabled, this allows the data being passed over SSL to be compressed, however some servers are not compatible with this extension.
QSsl::SslOptionDisableServerNameIndication 0x08 Disables the SSL server name indication extension. When enabled, this tells the server the virtual host being accessed allowing it to respond with the correct certificate.
QSsl::SslOptionDisableLegacyRenegotiation 0x10 Disables the older insecure mechanism for renegotiating the connection parameters. When enabled, this option can allow connections for legacy servers, but it introduces the possibility that an attacker could inject plaintext into the SSL session.
QSsl::SslOptionDisableSessionSharing 0x20 Disables SSL session sharing via the session ID handshake attribute.
QSsl::SslOptionDisableSessionPersistence 0x40 Disables storing the SSL session in ASN.1 format as returned by QSslConfiguration::sessionTicket(). Enabling this feature adds memory overhead of approximately 1K per used session ticket.
QSsl::SslOptionDisableServerCipherPreference 0x80 Disables selecting the cipher chosen based on the servers preferences rather than the order ciphers were sent by the client. This option is only relevant to server sockets, and is only honored by the OpenSSL backend.

By default, SslOptionDisableEmptyFragments is turned on since this causes problems with a large number of servers. SslOptionDisableLegacyRenegotiation is also turned on, since it introduces a security risk. SslOptionDisableCompression is turned on to prevent the attack publicised by CRIME. SslOptionDisableSessionPersistence is turned on to optimize memory usage. The other options are turned off.

Note: Availability of above options depends on the version of the SSL backend in use.

The SslOptions type is a typedef for QFlags<SslOption>. It stores an OR combination of SslOption values.

enum QSsl::SslProtocol

Describes the protocol of the cipher.

Constant Value Description
QSsl::TlsV1_0 0 TLSv1.0
QSsl::TlsV1_0OrLater 5 TLSv1.0 and later versions.
QSsl::TlsV1_1 1 TLSv1.1.
QSsl::TlsV1_1OrLater 6 TLSv1.1 and later versions.
QSsl::TlsV1_2 2 TLSv1.2.
QSsl::TlsV1_2OrLater 7 TLSv1.2 and later versions.
QSsl::DtlsV1_0 8 DTLSv1.0
QSsl::DtlsV1_0OrLater 9 DTLSv1.0 and later versions.
QSsl::DtlsV1_2 10 DTLSv1.2
QSsl::DtlsV1_2OrLater 11 DTLSv1.2 and later versions.
QSsl::TlsV1_3 12 TLSv1.3. (Since Qt 5.12)
QSsl::TlsV1_3OrLater 13 TLSv1.3 and later versions. (Since Qt 5.12)
QSsl::UnknownProtocol -1 The cipher's protocol cannot be determined.
QSsl::AnyProtocol 3 Any supported protocol. This value is used by QSslSocket only.
QSsl::SecureProtocols 4 The default option, using protocols known to be secure.

[since 6.1] enum class SupportedFeature

Enumerates possible features that a TLS backend supports

In QtNetwork TLS-related classes have public API, that may be left unimplemented by some backend, for example, our SecureTransport backend does not support server-side ALPN. Enumerators from SupportedFeature enum indicate that a particular feature is supported.

Constant Value Description
QSslSocket::SupportedFeature::CertificateVerification 0 Indicates that QSslCertificate::verify() is implemented by the backend.
QSslSocket::SupportedFeature::ClientSideAlpn 1 Client-side ALPN (Application Layer Protocol Negotiation).
QSslSocket::SupportedFeature::ServerSideAlpn 2 Server-side ALPN.
QSslSocket::SupportedFeature::Ocsp 3 OCSP stapling (Online Certificate Status Protocol).
QSslSocket::SupportedFeature::Psk 4 Pre-shared keys.
QSslSocket::SupportedFeature::SessionTicket 5 Session tickets.
QSslSocket::SupportedFeature::Alerts 6 Information about alert messages sent and received.

This enum was introduced or modified in Qt 6.1.

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