A method for authenticating an Internet Protocol Security (IPsec) packet, wherein the method comprises, receiving the IPsec packet via an input port, performing a Sequence-Integrity Check Value (SEQ-ICV) check that validates a sequence number within the IPsec packet, and performing an Integrity Check Value (ICV) check that validates a checksum within the IPsec packet, wherein the SEQ-ICV check is performed before the ICV check. In yet another example embodiment, an apparatus for transmitting an IPsec packet, comprising a processor, and a transmitter coupled to the processor, wherein the transmitter is configured to transmit an IPsec packet that comprises a header that comprises a sequence number field that provides a sequence number, and a payload that comprises one or more SEQ-ICV segments used to authenticate the sequence number within the IPsec packet.