A method for implementing a secure stream protocol to secure an interconnect link (815, 825) between an initiating device and a target device, comprising: configuring the secure stream protocol in a restricted ordering mode, if an interconnect protocol of the interconnect link (815, 825) allows but does not require reordering of a first type of transaction over a second type of transaction, or in an explicit counter mode if the interconnect protocol requires reordering of the first type of transaction over the second type of transaction; setting an indication in a transaction of a stream of transactions to be sent from the initiating device to the target device, the indication indicating that the secure stream protocol is configured in the restricted ordering mode or the explicit counter mode, the transaction being of the first type of transaction or the second type of transaction; if the secure stream protocol is configured in the explicit counter mode, including a counter used for encryption in the transaction and, if the secure stream protocol is configured in the restricted ordering mode, not including the counter in the transaction, the counter allowing to detect whether transactions of the stream were received at the target device in an order in which the transactions of the stream were sent by the initiating device; and sending the transaction of the stream from the initiating device to the target device over the interconnect link (815, 825), the transaction traversing one or more intermediate devices from the initiating device to the target device, wherein the indication in the transaction set to the restricted ordering mode indicates to the one or more intermediate devices that reordering the first type of transaction over the second type of transaction is not allowed such that transactions of the stream are received at the target device in the order in which the transactions of the stream were sent by the initiating device, and wherein the indication in the transaction set to the explicit counter mode indicates to the one or more intermediate devices that reordering the first type of transaction over the second type of transaction is allowed. configuring the secure stream protocol in a restricted ordering mode, if an interconnect protocol of the interconnect link (815, 825) allows but does not require reordering of a first type of transaction over a second type of transaction, or in an explicit counter mode if the interconnect protocol requires reordering of the first type of transaction over the second type of transaction; setting an indication in a transaction of a stream of transactions to be sent from the initiating device to the target device, the indication indicating that the secure stream protocol is configured in the restricted ordering mode or the explicit counter mode, the transaction being of the first type of transaction or the second type of transaction; if the secure stream protocol is configured in the explicit counter mode, including a counter used for encryption in the transaction and, if the secure stream protocol is configured in the restricted ordering mode, not including the counter in the transaction, the counter allowing to detect whether transactions of the stream were received at the target device in an order in which the transactions of the stream were sent by the initiating device; and sending the transaction of the stream from the initiating device to the target device over the interconnect link (815, 825), the transaction traversing one or more intermediate devices from the initiating device to the target device, wherein the indication in the transaction set to the restricted ordering mode indicates to the one or more intermediate devices that reordering the first type of transaction over the second type of transaction is not allowed such that transactions of the stream are received at the target device in the order in which the transactions of the stream were sent by the initiating device, and wherein the indication in the transaction set to the explicit counter mode indicates to the one or more intermediate devices that reordering the first type of transaction over the second type of transaction is allowed.