The DTLS transport supports the ability to use different cipher suites for a given PubSub Connection. This is configured via the ConnectionProperties of the PubSubConnectionDataType structure. A default value is configured in the ConfigurationProperties of the PubSubConfiguration. The properties are defined through the KeyValuePair array in the ConnectionProperties. The NamespaceIndex of the QualifiedName in the KeyValuePair shall be 0 for DTLS standard properties. The Name of the QualifiedName is constructed from a prefix and the DTLS property name with the following syntax. The intended use is for the DTLS client to include a single cipher suite in the handshake, which is the cipher suite to be used for that connection. To facilitate this, the DTLS server may have a list of cipher suites that are accepted if sent by a DTLS client in the handshake.

The NamespaceIndex of the QualifiedName in the KeyValuePair for properties defined in this document shall be 0. The Name of the QualifiedName is the property key from Table 202. The DataType of the Value in the KeyValuePair shall be the DataType defined in Table 202.

Table 202 formally defines the DTLS configuration properties

Table 196 – OPC UA DTLS standard properties

Key	DataTypes	Description
0:DtlsConnectionSettings	DtlsPubSubConnectionDataType	The DTLS configuration for the PubSubConnection or WriterGroup. The DtlsPubSubConnectionDataType is defined in 6.4.1.7.6.
0:DtlsClientCipherSuite	String	Cipher suite for the PubSubConnection or WriterGroup. The ClientCipherSuite is defined in 6.4.1.7.1.