This International Standard provides a standard interface to hardware biometric modules designed to be integrated in embedded systems which can be constrained in memory and computational power. This International Standard specifies a full interface for such hardware-based biometric modules. This interface@ called Embedded BioAPI@ is defined by the specification of commands to be implemented by these modules. Such a specification is done in two levels: ?? For low level implementations@ a frame definition is provided@ as well as the coding of all commands and their relevant responses. Being defined as a single-master/multiple-slave half-duplex protocol@ these messages can be implemented over any communication interface at the physical and link layers. The definition of such communication interfaces is outside of the scope of this International Standard. ?? A C-based function header description@ for those manufacturers that want to provide a C-library for integration as a Software Development Kit for the overall embedded system. Regarding security@ this International Standard defines two kinds of devices: ?? Type A: devices that@ due to lack of processing capabilities@ do not implement any kind of security mechanism. ?? Type B: devices that implement security mechanisms for achieving confidentiality@ integrity and/or authenticity. Use of the Type B kind of devices is recommended. For Type B devices a set of minimum requirements is defined@ but the security mechanisms to be used are out of the scope of this International Standard. Low level implementation is outside of the scope of the normative part of this International Standard@ although an informative annex (see Annex B) is provided. Security mechanisms@ although considered in this International Standard@ are outside of the scope of this International Standard@ and are referred to other relevant standards. In particular@ key management is outside of the scope of this International Standard@ and is expected to be done prior to the application of this International Standard. Specifications and requirements for Embedded BioAPI subcomponents@ or any kind of devices suitable to implement Embedded BioAPI@ are outside of the scope of this International Standard.