Read-and-write property specifying the security policy or encryption used when connecting to an OPC UA server. This property cannot be changed while communication is active. Possible values for this property are 1 - uspNone: Does not use encryption in the connection (default), 2 - uspBasic128Rsa15: Uses the RSA algorithm with a 128-bit key in the connection, 3 - uspBasic256: Uses the AES algorithm with a 256-bit key in the connection, 4 - uspBasic256Sha256: Uses the SHA algorithm with a 256-bit key in the connection, 5 - uspAes128_Sha256_RsaOaep: Uses the SHA algorithm with a 256-bit key combined with the RSA algorithm and the OAEP (Optimal Asymmetric Encryption Padding) method in the connection, or 6 - uspAes256_Sha256_RsaPss: Uses the SHA algorithm with a 256-bit key combined with the RSA algorithm and the PSS (Probabilistic Signature Scheme) method in the connection. This property is used together with the SecurityMode property to determine the type of security of a connection.