Network Working Group                                        H. Nakajima
Internet-Draft                                             Mercari, Inc.
Intended status: Informational                              June 7, 2018
Expires: December 9, 2018


       General Security Considerations for Crypto Assets Exchange
          draft-vcgtf-crypto-assets-security-considerations-00

Abstract

   This document discusses the threat, risk, and controls on the
   followings; Online system of crypto assets exchange that provides the
   exchange service to its customer (consumers and trade partners);
   assets information (including the private key of the crypto assets)
   that the online system of a crypto assets exchange manages; Social
   impact that can arise from the discrepancy in the security measures
   that are implemented in the online system of a crypto assets
   exchange.

   This document is applicable to the crypto assets exchanges that
   manages the private key that corresponds to the crypto assets.  It
   includes the organizations that outsources the key management to
   another organization.  In such a case, the certain recommendations
   applies to those outsourcers.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 9, 2018.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Scope of this document  . . . . . . . . . . . . . . . . . . .   3
   3.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   4.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Basic description of a model online system of a crypto assets
       exchange  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     5.1.  General . . . . . . . . . . . . . . . . . . . . . . . . .   3
     5.2.  A basic model of online system of a crypto assets
           exchange and its functional components  . . . . . . . . .   3
     5.3.  The flow leading to the sending of the transaction  . . .   4
     5.4.  Types of keys that are used for signature and encryption    4
       5.4.1.  Type of keys  . . . . . . . . . . . . . . . . . . . .   4
       5.4.2.  A flow for the key generation and the key usage . . .   4
       5.4.3.  On the usage of multiple keys . . . . . . . . . . . .   4
       5.4.4.  On the suspension of keys . . . . . . . . . . . . . .   4
     5.5.  On the characteristics of crypto assets on Blockchain and
           distributed ledger technologies . . . . . . . . . . . . .   4
       5.5.1.  General . . . . . . . . . . . . . . . . . . . . . . .   4
       5.5.2.  The importance of the private key used for signing  .   4
       5.5.3.  Diversity of implementations  . . . . . . . . . . . .   4
       5.5.4.  Risk on the unapproved transactions . . . . . . . . .   4
   6.  Basic objectives for the security management of crypto assets
       exchanges . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   7.  Approaches to basic security controls . . . . . . . . . . . .   4
   8.  Sector specific security management controls for crypto
       assets exchanges  . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  General . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.2.  On the direction of the information security management .   5
     8.3.  On the controls for key recovery  . . . . . . . . . . . .   5
     8.4.  On the controls against theft and leakage of the private
           key for signing . . . . . . . . . . . . . . . . . . . . .   5
     8.5.  On the illegal operation of the private key for signing .   5
     8.6.  On the illegal operation against the assets data  . . . .   5
     8.7.  On the user authentication  . . . . . . . . . . . . . . .   5
     8.8.  On the withdrawal of the coins  . . . . . . . . . . . . .   5
     8.9.  On the transfer of the crypto assets to an unused address   5



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   9.  Remaining issues  . . . . . . . . . . . . . . . . . . . . . .   5
   10. Security Considerations . . . . . . . . . . . . . . . . . . .   5
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   12. Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Appendix A.  Contributors . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   TODO Introduction

2.  Scope of this document

   In this document, crypto assets exchange operators which hold a
   private key of crypto assets.

3.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

4.  Terminology

   o  Wallet

   o  Fork of blockchain

5.  Basic description of a model online system of a crypto assets
    exchange

5.1.  General

   In this clause, a model online system of a crypto assets exchange
   that is used to explain the concepts and provisions in this document
   are explained.

5.2.  A basic model of online system of a crypto assets exchange and its
      functional components

   Followings are the basic model of a crypto assets exchange that this
   document deals with.







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5.3.  The flow leading to the sending of the transaction

5.4.  Types of keys that are used for signature and encryption

5.4.1.  Type of keys

5.4.2.  A flow for the key generation and the key usage

5.4.3.  On the usage of multiple keys

5.4.4.  On the suspension of keys

5.5.  On the characteristics of crypto assets on Blockchain and
      distributed ledger technologies

5.5.1.  General

5.5.2.  The importance of the private key used for signing

5.5.3.  Diversity of implementations

5.5.3.1.  On the cryptographic algorithms used by crypto assets

5.5.3.2.  On the possibility of the forking of the Blockchain

5.5.3.3.  Rollback by reorganization

5.5.3.4.  The treatment of the forked crypto assets

5.5.4.  Risk on the unapproved transactions

5.5.4.1.  General

5.5.4.2.  The handling of the unapproved transactions

5.5.4.3.  Transaction failures caused by the vulnerabilities of the
          implementation or the specification of the crypto assets

6.  Basic objectives for the security management of crypto assets
    exchanges

7.  Approaches to basic security controls









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8.  Sector specific security management controls for crypto assets
    exchanges

8.1.  General

8.2.  On the direction of the information security management

8.3.  On the controls for key recovery

8.4.  On the controls against theft and leakage of the private key for
      signing

8.5.  On the illegal operation of the private key for signing

8.6.  On the illegal operation against the assets data

8.7.  On the user authentication

8.8.  On the withdrawal of the coins

8.9.  On the transfer of the crypto assets to an unused address

9.  Remaining issues

10.  Security Considerations

   TODO Security

11.  IANA Considerations

   This document has no IANA actions.

12.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

Appendix A.  Contributors







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Author's Address

   Hirotaka Nakajima
   Mercari, Inc.

   Email: hiro@awa.sfc.keio.ac.jp













































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