Digital signature systems and methods to represent network path trace information in a packet, implemented by a network element in a network include updating a digital signature based on a unique identifier of the network element, wherein the digital signature is carried in-band with the packet; and transmitting the packet by the network element with the updated digital signature, wherein the digital signature represents the network path trace information of the packet up to the network element. The digital signature is a key carried in-band with the packet, and the updating can include performing an exclusive OR function with a current key and a Cyclic Redundancy Check (CRC) of a bit field with the unique identifier included therein to derive a new key which is inserted as the digital signature in the packet.