The system as a PACS(picture archiving and communication system), which handles medical image, saves patient's medical image information and transports them. This needs security processor for user's authentication and encrypted information based on PKI(public key infrastructure). The DICOM (digital imaging communications in medicine), which is a standard of PACS's transmission, has adopted RSA(Rivest Shamir Adleman) in the authentication and transmission, which is public key algorithm. However, in embedded medical image system using low power and restricted hardware resource, it's long key size is an important problem on the hardware implementation and processing time. Moreover, the public key algorithm, ECC(elliptic curve cryptography) supported higher security than those of RSA in the same key size. In this paper, the DICOM security standard RSA is substituted for ECC and we implemented it. ECC is implemented on GF(2/sup 163/) using polynomial base. Finite field operating used Montgomery algorithm and Brunner Extended Euclidian algorithm. ECC point multiplication operating used Radix-4 scalar multiplication. And we verified it on ISE 6.2 software using the Xilinx Vertex 1000E FPGA. Finally, we designed and verified it by semi-custom ASIC design.