An example method includes, in response to receiving a byte array including process data, determining whether auxiliary data is to be transmitted from a field device based on a counter, the auxiliary data including an encryption key identifier and an initialization vector, when auxiliary data is to be transmitted, transmitting a first data packet including the auxiliary data to the remote device, and determining a value for a source bit based on a type of connection between the field device and the remote device, the source bit and the counter included in associated data. The method further includes generating a nonce value based on the source bit and the initialization vector, encrypting a payload including the byte array based on the encryption key identifier and the nonce value, and transmitting a second data packet to the remote device, the second data packet including the associated data and the encrypted payload.