Many sensor network applications rely on sensors' location information. However, most of existing location algorithms assume a non-adversarial environment or assume beacons lying within 1-hop. In this paper, we fo- cus on Hop-Count based localization (multihop) and de- velop a Secure HOp-Count based LOCalization scheme, called SHOLOC, to make localization attack-resistant. In SHOLOC, we assume both ordinary nodes and bea- con nodes can be moving, and the whole network period- ically restarts localization. SHOLOC proposes a proto- col to authenticate beacon information and protect hop- count from being arbitrary changed. SHOLOC employs beacon nodes to detect wormhole attacks. Theoretical analysis and simulation results are presented. Our con- clusion also includes two interest findings: 1)hop-count increment attacks are not effective to Hop-Count based algorithms, 2)filter mechanisms such as least median squares (LMS) are not resistant to wormhole attacks, and our method of detecting at beacon nodes side works well.