- Qt 6.8
- Qt Network
- C++ Classes
- QSslCertificate
- Qt 6.8.1 Reference Documentation

# QSslCertificate Class

The QSslCertificate class provides a convenient API for an X509 certificate. More...

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

- List of all members, including inherited members
- QSslCertificate is part of Network Programming API and Implicitly Shared Classes.

Note: All functions in this class are reentrant.

## Public Types

enum class | PatternSyntax { RegularExpression, Wildcard, FixedString }
enum | SubjectInfo { Organization, CommonName, LocalityName, OrganizationalUnitName, CountryName, …, EmailAddress }

## Public Functions

| QSslCertificate(QIODevice *device, QSsl::EncodingFormat format = QSsl::Pem)
| QSslCertificate(const QByteArray &data = QByteArray(), QSsl::EncodingFormat format = QSsl::Pem)
| QSslCertificate(const QSslCertificate &other)
`(since 6.8)` | QSslCertificate(QSslCertificate &&other)
| ~QSslCertificate()
void | clear()
QByteArray | digest(QCryptographicHash::Algorithm algorithm = QCryptographicHash::Md5) const
QDateTime | effectiveDate() const
QDateTime | expiryDate() const
QList<QSslCertificateExtension> | extensions() const
Qt::HANDLE | handle() const
bool | isBlacklisted() const
bool | isNull() const
bool | isSelfSigned() const
QString | issuerDisplayName() const
QStringList | issuerInfo(QSslCertificate::SubjectInfo subject) const
QStringList | issuerInfo(const QByteArray &attribute) const
QList<QByteArray> | issuerInfoAttributes() const
QSslKey | publicKey() const
QByteArray | serialNumber() const
QMultiMap<QSsl::AlternativeNameEntryType, QString> | subjectAlternativeNames() const
QString | subjectDisplayName() const
QStringList | subjectInfo(QSslCertificate::SubjectInfo subject) const
QStringList | subjectInfo(const QByteArray &attribute) const
QList<QByteArray> | subjectInfoAttributes() const
void | swap(QSslCertificate &other)
QByteArray | toDer() const
QByteArray | toPem() const
QString | toText() const
QByteArray | version() const
bool | operator!=(const QSslCertificate &other) const
QSslCertificate & | operator=(const QSslCertificate &other)
bool | operator==(const QSslCertificate &other) const

## Static Public Members

QList<QSslCertificate> | fromData(const QByteArray &data, QSsl::EncodingFormat format = QSsl::Pem)
QList<QSslCertificate> | fromDevice(QIODevice *device, QSsl::EncodingFormat format = QSsl::Pem)
QList<QSslCertificate> | fromPath(const QString &path, QSsl::EncodingFormat format = QSsl::Pem, QSslCertificate::PatternSyntax syntax = PatternSyntax::FixedString)
bool | importPkcs12(QIODevice *device, QSslKey *key, QSslCertificate *certificate, QList<QSslCertificate> *caCertificates = nullptr, const QByteArray &passPhrase = QByteArray())
QList<QSslError> | verify(const QList<QSslCertificate> &certificateChain, const QString &hostName = QString())

## Detailed Description

QSslCertificate stores an X509 certificate, and is commonly used to verify the identity and store information about the local host, a remotely connected peer, or a trusted third party Certificate Authority.

There are many ways to construct a QSslCertificate. The most common way is to call QSslSocket::peerCertificate(), which returns a QSslCertificate object, or QSslSocket::peerCertificateChain(), which returns a list of them. You can also load certificates from a DER (binary) or PEM (Base64) encoded bundle, typically stored as one or more local files, or in a Qt Resource.

You can call isNull() to check if your certificate is null. By default, QSslCertificate constructs a null certificate. A null certificate is invalid, but an invalid certificate is not necessarily null. If you want to reset all contents in a certificate, call clear().

After loading a certificate, you can find information about the certificate, its subject, and its issuer, by calling one of the many accessor functions, including version(), serialNumber(), issuerInfo() and subjectInfo(). You can call effectiveDate() and expiryDate() to check when the certificate starts being effective and when it expires. The publicKey() function returns the certificate subject's public key as a QSslKey. You can call issuerInfo() or subjectInfo() to get detailed information about the certificate issuer and its subject.

Internally, QSslCertificate is stored as an X509 structure. You can access this handle by calling handle(), but the results are likely to not be portable.

See also QSslSocket, QSslKey, QSslCipher, and QSslError.

## Member Type Documentation

### enum class QSslCertificate::PatternSyntax

The syntax used to interpret the meaning of the pattern.

Constant | Value | Description
--- | --- | ---
`QSslCertificate::PatternSyntax::RegularExpression` | `0` | A rich Perl-like pattern matching syntax.
`QSslCertificate::PatternSyntax::Wildcard` | `1` | This provides a simple pattern matching syntax similar to that used by shells (command interpreters) for "file globbing". See QRegularExpression::fromWildcard().
`QSslCertificate::PatternSyntax::FixedString` | `2` | The pattern is a fixed string. This is equivalent to using the RegularExpression pattern on a string in which all metacharacters are escaped using escape(). This is the default.

### enum QSslCertificate::SubjectInfo

Describes keys that you can pass to QSslCertificate::issuerInfo() or QSslCertificate::subjectInfo() to get information about the certificate issuer or subject.

Constant | Value | Description
--- | --- | ---
`QSslCertificate::Organization` | `0` | "O" The name of the organization.
`QSslCertificate::CommonName` | `1` | "CN" The common name; most often this is used to store the host name.
`QSslCertificate::LocalityName` | `2` | "L" The locality.
`QSslCertificate::OrganizationalUnitName` | `3` | "OU" The organizational unit name.
`QSslCertificate::CountryName` | `4` | "C" The country.
`QSslCertificate::StateOrProvinceName` | `5` | "ST" The state or province.
`QSslCertificate::DistinguishedNameQualifier` | `6` | The distinguished name qualifier
`QSslCertificate::SerialNumber` | `7` | The certificate's serial number
`QSslCertificate::EmailAddress` | `8` | The email address associated with the certificate

## Member Function Documentation

### `[explicit]` QSslCertificate::QSslCertificate(QIODevice *device, QSsl::EncodingFormat format = QSsl::Pem)

Constructs a QSslCertificate by reading format encoded data from device and using the first certificate found. You can later call isNull() to see if device contained a certificate, and if this certificate was loaded successfully.

### `[explicit]` QSslCertificate::QSslCertificate(const QByteArray &data = QByteArray(), QSsl::EncodingFormat format = QSsl::Pem)

Constructs a QSslCertificate by parsing the format encoded data and using the first available certificate found. You can later call isNull() to see if data contained a certificate, and if this certificate was loaded successfully.

### QSslCertificate::QSslCertificate(const QSslCertificate &other)

Constructs an identical copy of other.

### `[constexpr noexcept, since 6.8]` QSslCertificate::QSslCertificate(QSslCertificate &&other)

Move-constructs a new QSslCertificate from other.

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

This function was introduced in Qt 6.8.

### `[noexcept]` QSslCertificate::~QSslCertificate()

Destroys the QSslCertificate.

### void QSslCertificate::clear()

Clears the contents of this certificate, making it a null certificate.

See also isNull().

### QByteArray QSslCertificate::digest(QCryptographicHash::Algorithm algorithm = QCryptographicHash::Md5) const

Returns a cryptographic digest of this certificate. By default, an MD5 digest will be generated, but you can also specify a custom algorithm.

### QDateTime QSslCertificate::effectiveDate() const

Returns the date-time that the certificate becomes valid, or an empty QDateTime if this is a null certificate.

See also expiryDate().

### QDateTime QSslCertificate::expiryDate() const

Returns the date-time that the certificate expires, or an empty QDateTime if this is a null certificate.

See also effectiveDate().

### QList<QSslCertificateExtension> QSslCertificate::extensions() const

Returns a list containing the X509 extensions of this certificate.

### `[static]` QList<QSslCertificate> QSslCertificate::fromData(const QByteArray &data, QSsl::EncodingFormat format = QSsl::Pem)

Searches for and parses all certificates in data that are encoded in the specified format and returns them in a list of certificates.

See also fromDevice().

### `[static]` QList<QSslCertificate> QSslCertificate::fromDevice(QIODevice *device, QSsl::EncodingFormat format = QSsl::Pem)

Searches for and parses all certificates in device that are encoded in the specified format and returns them in a list of certificates.

See also fromData().

### `[static]` QList<QSslCertificate> QSslCertificate::fromPath(const QString &path, QSsl::EncodingFormat format = QSsl::Pem, QSslCertificate::PatternSyntax syntax = PatternSyntax::FixedString)

Searches all files in the path for certificates encoded in the specified format and returns them in a list. path must be a file or a pattern matching one or more files, as specified by syntax.

Example:

     const auto certs = QSslCertificate::fromPath("C:/ssl/certificate.*.pem",
                                                  QSsl::Pem, QSslCertificate::Wildcard);
     for (const QSslCertificate &cert : certs) {
         qDebug() << cert.issuerInfo(QSslCertificate::Organization);
     }

See also fromData().

### Qt::HANDLE QSslCertificate::handle() const

Returns a pointer to the native certificate handle, if there is one, else `nullptr`.

You can use this handle, together with the native API, to access extended information about the certificate.

Warning: Use of this function has a high probability of being non-portable, and its return value may vary from platform to platform or change from minor release to minor release.

### `[static]` bool QSslCertificate::importPkcs12(QIODevice *device, QSslKey *key, QSslCertificate *certificate, QList<QSslCertificate> *caCertificates = nullptr, const QByteArray &passPhrase = QByteArray())

Imports a PKCS#12 (pfx) file from the specified device. A PKCS#12 file is a bundle that can contain a number of certificates and keys. This method reads a single key, its certificate and any associated caCertificates from the bundle. If a passPhrase is specified then this will be used to decrypt the bundle. Returns `true` if the PKCS#12 file was successfully loaded.

Note: The device must be open and ready to be read from.

### bool QSslCertificate::isBlacklisted() const

Returns `true` if this certificate is blacklisted; otherwise returns `false`.

See also isNull().

### bool QSslCertificate::isNull() const

Returns `true` if this is a null certificate (i.e., a certificate with no contents); otherwise returns `false`.

By default, QSslCertificate constructs a null certificate.

See also clear().

### bool QSslCertificate::isSelfSigned() const

Returns `true` if this certificate is self signed; otherwise returns `false`.

A certificate is considered self-signed its issuer and subject are identical.

### QString QSslCertificate::issuerDisplayName() const

Returns a name that describes the issuer. It returns the QSslCertificate::CommonName if available, otherwise falls back to the first QSslCertificate::Organization or the first QSslCertificate::OrganizationalUnitName.

See also issuerInfo().

### QStringList QSslCertificate::issuerInfo(QSslCertificate::SubjectInfo subject) const

Returns the issuer information for the subject from the certificate, or an empty list if there is no information for subject in the certificate. There can be more than one entry of each type.

See also subjectInfo().

### QStringList QSslCertificate::issuerInfo(const QByteArray &attribute) const

Returns the issuer information for attribute from the certificate, or an empty list if there is no information for attribute in the certificate. There can be more than one entry for an attribute.

See also subjectInfo().

### QList<QByteArray> QSslCertificate::issuerInfoAttributes() const

Returns a list of the attributes that have values in the issuer information of this certificate. The information associated with a given attribute can be accessed using the issuerInfo() method. Note that this list may include the OIDs for any elements that are not known by the SSL backend.

See also subjectInfo().

### QSslKey QSslCertificate::publicKey() const

Returns the certificate subject's public key.

### QByteArray QSslCertificate::serialNumber() const

Returns the certificate's serial number string in hexadecimal format.

### QMultiMap<QSsl::AlternativeNameEntryType, QString> QSslCertificate::subjectAlternativeNames() const

Returns the list of alternative subject names for this certificate. The alternative names typically contain host names, optionally with wildcards, that are valid for this certificate.

These names are tested against the connected peer's host name, if either the subject information for CommonName doesn't define a valid host name, or the subject info name doesn't match the peer's host name.

See also subjectInfo().

### QString QSslCertificate::subjectDisplayName() const

Returns a name that describes the subject. It returns the QSslCertificate::CommonName if available, otherwise falls back to the first QSslCertificate::Organization or the first QSslCertificate::OrganizationalUnitName.

See also subjectInfo().

### QStringList QSslCertificate::subjectInfo(QSslCertificate::SubjectInfo subject) const

Returns the information for the subject, or an empty list if there is no information for subject in the certificate. There can be more than one entry of each type.

See also issuerInfo().

### QStringList QSslCertificate::subjectInfo(const QByteArray &attribute) const

Returns the subject information for attribute, or an empty list if there is no information for attribute in the certificate. There can be more than one entry for an attribute.

See also issuerInfo().

### QList<QByteArray> QSslCertificate::subjectInfoAttributes() const

Returns a list of the attributes that have values in the subject information of this certificate. The information associated with a given attribute can be accessed using the subjectInfo() method. Note that this list may include the OIDs for any elements that are not known by the SSL backend.

See also subjectInfo().

### `[noexcept]` void QSslCertificate::swap(QSslCertificate &other)

Swaps this certificate instance with other. This function is very fast and never fails.

### QByteArray QSslCertificate::toDer() const

Returns this certificate converted to a DER (binary) encoded representation.

### QByteArray QSslCertificate::toPem() const

Returns this certificate converted to a PEM (Base64) encoded representation.

### QString QSslCertificate::toText() const

Returns this certificate converted to a human-readable text representation.

### `[static]` QList<QSslError> QSslCertificate::verify(const QList<QSslCertificate> &certificateChain, const QString &hostName = QString())

Verifies a certificate chain. The chain to be verified is passed in the certificateChain parameter. The first certificate in the list should be the leaf certificate of the chain to be verified. If hostName is specified then the certificate is also checked to see if it is valid for the specified host name.

Note that the root (CA) certificate should not be included in the list to be verified, this will be looked up automatically using the CA list specified in the default QSslConfiguration, and, in addition, if possible, CA certificates loaded on demand on Unix and Windows.

### QByteArray QSslCertificate::version() const

Returns the certificate's version string.

### bool QSslCertificate::operator!=(const QSslCertificate &other) const

Returns `true` if this certificate is not the same as other; otherwise returns `false`.

### QSslCertificate &QSslCertificate::operator=(const QSslCertificate &other)

Copies the contents of other into this certificate, making the two certificates identical.

### bool QSslCertificate::operator==(const QSslCertificate &other) const

Returns `true` if this certificate is the same as other; otherwise returns `false`.