Systems, methods, and media for retransmitting data using the SRTP are provided. In some embodiments, methods for retransmitting data using the SRTP are provided. The methods include: receiving at least one data unit associated with a media session; determining the index of the at least one data unit; determining the session key of the media session using the index; authenticating the at least one data unit using the session key; and retransmitting the at least one data unit.