Security and privacy in RFID systems is an important and active research area. A number of challenges arise due to the extremely limited computational, storage and communication abilities of a typical RFID tag. This work describes a simple technique for inexpensive untraceable identification of RFID tags. The proposed protocol (called YA-TRAP) involves minimal interaction between a tag and a reader and places low computational burden on the tag (a single keyed hash). It also imposes low computational load on the back-end server.