Qt OPC UA X509 Support Example | Qt OPC UA 6.1.3

- Qt 6.1
- Qt OPC UA
- Qt OPC UA Examples
- Qt OPC UA X509 Support Example
- Qt 6.1.3 Reference Documentation

# Qt OPC UA X509 Support Example

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     #include <QOpcUaProvider>
     #include <QOpcUaKeyPair>
     #include <QOpcUaX509CertificateSigningRequest>
     #include <QOpcUaX509ExtensionSubjectAlternativeName>
     #include <QOpcUaX509ExtensionBasicConstraints>
     #include <QOpcUaX509ExtensionKeyUsage>
     #include <QFile>

     int main(int argc, char **argv)
     {
         Q_UNUSED(argc);
         Q_UNUSED(argv);

         // Generate RSA Key
         QOpcUaKeyPair key;
         key.generateRsaKey(QOpcUaKeyPair::RsaKeyStrength::Bits1024);

         // Save private key to file
         QByteArray keyData = key.privateKeyToByteArray(QOpcUaKeyPair::Cipher::Aes128Cbc, "password");

         QFile keyFile("privateKey.pem");
         keyFile.open(QFile::WriteOnly);
         keyFile.write(keyData);
         keyFile.close();

         // Create a certificate signing request
         QOpcUaX509CertificateSigningRequest csr;

         // Set the subject of the certificate
         QOpcUaX509DistinguishedName dn;
         dn.setEntry(QOpcUaX509DistinguishedName::Type::CommonName, "QtOpcUaViewer");
         dn.setEntry(QOpcUaX509DistinguishedName::Type::CountryName, "DE");
         dn.setEntry(QOpcUaX509DistinguishedName::Type::LocalityName, "Berlin");
         dn.setEntry(QOpcUaX509DistinguishedName::Type::StateOrProvinceName, "Berlin");
         dn.setEntry(QOpcUaX509DistinguishedName::Type::OrganizationName, "The Qt Company");
         csr.setSubject(dn);

         // The subject alternative name extension is needed for OPC UA
         QOpcUaX509ExtensionSubjectAlternativeName *san = new QOpcUaX509ExtensionSubjectAlternativeName;
         san->addEntry(QOpcUaX509ExtensionSubjectAlternativeName::Type::DNS, "foo.com");
         san->addEntry(QOpcUaX509ExtensionSubjectAlternativeName::Type::URI, "urn:foo.com:The%20Qt%20Company:QtOpcUaViewer");
         san->setCritical(true);
         csr.addExtension(san);

         // Set the certificate basic constraints
         QOpcUaX509ExtensionBasicConstraints *bc = new QOpcUaX509ExtensionBasicConstraints;
         bc->setCa(false);
         bc->setCritical(true);
         csr.addExtension(bc);

         // Set the key usage constraints
         QOpcUaX509ExtensionKeyUsage *ku = new QOpcUaX509ExtensionKeyUsage;
         ku->setCritical(true);
         ku->setKeyUsage(QOpcUaX509ExtensionKeyUsage::KeyUsage::DigitalSignature);
         ku->setKeyUsage(QOpcUaX509ExtensionKeyUsage::KeyUsage::NonRepudiation);
         ku->setKeyUsage(QOpcUaX509ExtensionKeyUsage::KeyUsage::KeyEncipherment);
         ku->setKeyUsage(QOpcUaX509ExtensionKeyUsage::KeyUsage::DataEncipherment);
         ku->setKeyUsage(QOpcUaX509ExtensionKeyUsage::KeyUsage::CertificateSigning);
         csr.addExtension(ku);

         // Now there are two options:
         // 1. When you need to get your certificate signing request signed by a certificate authority
         //    you have to use the request data.
         // 2. When there is no certificate authority you have to self-sign the request.

         // Option 1
         QByteArray certificateSigingRequestData = csr.createRequest(key);

         // Option 2
         QByteArray selfSignedCertificateData = csr.createSelfSignedCertificate(key);

         return 0;
     }