Physically Unclonable Function (PUF) is a security primitive to address hardware security issues such as chip authentication, Intellectual Property (IP) protection etc. Conventional CMOS PUFs are built on delay (inverter chains, scan chains etc.) or memory structures (like SRAM). In this paper, we propose a novel PUF which works on the principles of spintronic Domain Wall Memory (DWM). Conventional DWM is limited by pinning due to process variations induced surface roughness of the nanowire. We exploit this limitation towards chip-authentication. We propose two flavors of PUFs namely relay-PUF and memory-PUF. The proposed PUFs show excellent entropy (measured by Hamming Distance). We also analyze metrics such as robustness, area and power of the DWM-PUFs. The memory-PUF indicated up to an order of magnitude reduction in power compared to SRAM PUF.