provided are a security device and a method for operating same . the security device may conceal an encryption key used for an encryption algorithm in an encryption module in correspondence to security attacks such as reading information on where the encryption key is stored in a memory by disassembling an ic chip , or extracting said information through microprobing . the encryption key may be included as a physical encryption key module in an encryption module , and a certain storage medium for storing the encryption key may be included in the encryption module . accordingly , the encryption key is not transmitted via a bus in a security device for encryption .