NIST IR 8202 Blockchain Technology Overview Dylan Yaga Peter Mell Nik Roby Karen Scarfone This publication is available free of charge from: https://doi.org/10.6028/ NIST.IR.8202 NISTIR 8202 Blockchain Technology Overview Dylan Yaga Peter Mell Computer Security Division Information Technology Laboratory Nik Roby G2, Inc. Annapolis Junction, MD Karen Scarfone Scarfone Cybersecurity Clifton, VA This publication is available free of charge from: https://doi.org/10.6028/ NIST.IR.8202 October 2018 U.S. Department of Commerce Wilbur L. Ross, Jr., Secretary National Institute of Standards and Technology Walter Copan , NIST Director and Under Secretary of Commerce for Standards and TechnologyNational Institute of Standards and Technology Internal Report 8202 66 pages ( October 2018 ) This publication is available free of charge from: https://doi.org/10.6028/ NIST.IR.8202 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification i s not intended to imply recommendation or endorsement by NIST, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. There may be references in this publication to other publications cur rently under development by NIST in accordance with its assigned statutory responsibilities. The information in this publication, including concepts and methodologies, may be used by f ederal agencies even before the completion of such companion publication s. Thus, until each publication is completed, current requirements, guideline s, and procedures, where they exist, remain operative. For planning and transition purposes, f ederal agencies may wish to closely follow the development of these new publications by NIST. Organizations are encouraged to review all draft publications during public comment periods and provide feedback to NIST. Many NIST cybersecurity publications , ot her than the ones noted above, are available at https://csrc.nist.gov/publications . Comments on this publication may be submitted to: National Institute of Standards and Technology Attn: Computer Security Division, Information Technology Laboratory 100 Bureau Drive (Mail Stop 8930) Gaithersburg, MD 20899 -8930 Email: nistir8202- comments@nist.gov All comments are subject to release under the Freedom of Information Act (FOIA). NISTIR 8202 BLOCKCHAIN TECHNOLOGY OVERVIEW ii This publication is available free of charge from: http s://doi.org/10.6028/ NIST.IR.8202 Reports on Computer Systems Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the Nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analyses to advance the development and productive use of information technology. ITL’s responsibilities include the development of management, administrative, technical, and physical standards and guidelines for the cost -effective security and privacy of other than national s ecurity -related information in federal informa tion systems. Abstract Blockchains are tamper evident and tamper resistant digital ledger s implemented in a distributed fashion (i.e., without a central repository) and usually without a central authority (i.e., a bank, company, or government). At their basic level, they enable a community of users to record transactions in a shared ledger within that community, such that under normal operation of the blockchain network no transaction can be changed once published. This document provide s a high- level technical overview of blockchain techn