A method, system, and computer product for use in generating one time passcodes (OTPs) in security environment, the security environment comprising an OTP generator and an OTP validator, the method comprising generating, at the OTP generator, an OTP according to a function, wherein the function includes as an input a device id, validating the OTP at the OTP validator, whereby the validation comprises generating, at the OTP validator, a second OTP according to the function, and determining whether the OTP is valid based on a comparison of the OTP with the second OTP generated at the OTP validator.