New Technologies applicable to Document Management: Blockchain Hrvoje Stancic, Ph.D., assoc. prof. Faculty of Humanities and Social Sciences University of Zagreb, Croatia hstancic@ffzg.hr

Contents Introduction eIDAS Regulation Hash function Hash (Merkle) tree Distributed network Blockchain Conclusion

1. Introduction Electronic Document Management – motivation business productivity organizational effectiveness The need for version tracking tracing steps (where/when the document was/is) in the business process verification of changes, document structure, contents trusted exchange of document (trusted third party)

1. Introduction … Electronic Document Management Challenges stand alone solutions cloud solutions Challenges dealing with digital signatures, seals, time stamps preservation of documents' authenticity integrity reliability usability non-repudiation security confidentiality

2. eIDAS Regulation Regulation (EU) No 910/2014 of the European Parliament and of the Council of 23 July 2014 on electronic identification and trust services for electronic transactions in the internal market and repealing Directive 1999/93/EC http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R0910&from=EN defines advanced electronic signatures qualified certificates electronic seals qualified electronic time stamps

2. eIDAS Regulation ... Advanced electronic signature – an electronic signature that (a) it is uniquely linked to the signatory (b) it is capable of identifying the signatory (c) it is created using means that the signatory can maintain under his sole control, and (d) it is linked to the data to which it relates in such a manner that any subsequent change of the data is detectable Firstly defined in: Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on a Community framework for electronic signatures

2. eIDAS Regulation ... Advanced e-signatures rely on qualified certificates guarantee the authenticity and the identity of the signatory are issued for the period of 2 to 5 years expire can be revoked (CRL – Certification Revocation List)

2. eIDAS Regulation ... Advanced electronic seals similar requirements as for the advanced e-signature with the difference that it relates to the creator instead of the signatory also relay on the qualified certificates

2. eIDAS Regulation ... Qualified electronic time stamps (a) binds the date and time to data in such a manner as to reasonably preclude the possibility of the data being changed undetectably (b) is based on an accurate time source linked to Coordinated Universal Time, and (c) is signed using an advanced electronic signature or sealed with an advanced electronic seal of the qualified trust service provider, or by some equivalent method Qualified trust service providers provide qualified validation service (granted the qualified status by the supervisory body).

2. eIDAS Regulation ... Qualified electronic time stamps use advanced electronic signatures and electronic seals Advanced electronic signatures and electronic seals rely on qualified certificates authenticity identity of the signatory

2. eIDAS – example of electronic signature Advanced electronic signature

2. eIDAS – example of electronic signature

2. eIDAS Regulation ... Challenges short expiration period possibilities of certificate revocation the need for resigning dependence on the certification authority(-ies), i.e. qualified trust service providers ("trusted third party")

Archival time stamp(s) 2. eIDAS Regulation ... Relies on ETSI standards ETSI EN 319 102-1 Electronic Signatures and Infrastructures (ESI); Procedures for Creation and Validation of AdES Digital Signatures Archival Timestamps Signature providing Long Term Availability and Integrity of Validation Material (B-LTA) Signature with Time (B-T) Signature with Long Term Validation Material (B-LT) Basic Signature (B-B) e-signature Time stamp Certificate and revocation data Archival time stamp(s) Signer's document Signed attributes

2. eIDAS – example of electronic signature

3. Hash function Hash or message digest one-way function that calculates the unique fix-length string out of any document of any size it is not possible to recreate the original document by knowing its hash (theoretically) extremely difficult and nearly impossible to create "collisions" i.e. meaningful records with the same hash value (produced by a given hash function)

3. Hash function … Different hash functions (e.g. Adler32, Haval, MD, RipeMD160, SHA, Tiger, Whirlpool etc.) result with hash values of different lengths Secure Hash Algorithm (SHA): e.g. SHA-256, SHA-512 Example: hash of a document (.docx) MD5: 614e8bb4b90a998a5faea456f7249741 SHA-256: 7d8c5b62dcb440233f7eaac1ec49e4c386b8089c37d69 ab51bc674b8877cb032

3. Hash function – example Online MD5, http://onlinemd5.com/ Received file Calculated hash Received hash

3. Hash function … Hash in combination with electronic signatures can be used to check record's integrity authenticity of electronic signature

3. Hash function … 1. Hash function Application of private key Hash e-sign. 7d8c5b... e-sign. 7d8c5b... Hash function 2. Hash = integrity check Application of public key e-sign. Hash 7d8c5b... electronic signature authenticity check

4. Hash (Merkle) tree Several (or many) hash values may be hashed together thus forming a Merkle or hash tree Merkle, R. C. (1982). Patent No. US19790072363 19790905. USA H(D1-D20) – "root/top hash" H – hash D – document H(D1-D10) H(D11-D20) […] […] H(D1) H(D10) H(D11) H(D20)

4. Hash (Merkle) tree – example Online MD5, http://onlinemd5.com/ Hash of the File1.docx Hash of the File2.docx Hash of the File3.txt Calculated root/top hash

≠ 4. Hash (Merkle) tree … Merkle (hash) tree used by Satoshi Nakamoto for creating virtual/crypto currency Bitcoin resulted with the evolvement of the blockchain technology blockchain is the underlying technology enabling Bitcoin and many other applications blockchain relies upon a distributed network and decentralized consensus ≠

5. Distributed network Distributed (peer-to-peer) network vs. centralised network – one central server vs. decentralised network – several centres all nodes (servers) are equal – no centre(s) no single point of control or attack Image source: http://bluenetworks.weebly.com/syngeneia-in-the-history-of-pergamon.html

5. Distributed network … Enables the concept of decentralized consensus every participant (node/server) records every event in its ledger ("main book"/database) consensus is used in order to ensure that all ledgers are the exact copies (i.e. are synchronised) to determine truth event (e.g. transaction or document) is valid only if qualified majority (50%+1 node) agrees upon it

6. Blockchain A linked scheme based on hash (Merkle) tree Hashes of individual events or files are created and timestamped The group of hashes are hashed (a block is created), timestamped and made public (over the distributed network) in regular intervals (e.g. every second, every minute, every 10 or 15 minutes etc.) Hash of the previous block is included in the next block (thus creating a chain of blocks)

6. Blockchain … Blockchain formation […] […] […] […] […] […]

6. Blockchain … […] […] […] […] Blocks' creation direction Block n Hash of the previous block Top hash Block hash Hash of the previous block Top hash Block hash […] […] […] […] Block documents Block documents

6. Blockchain – example An example from the Enigio Time's time:beat solution (https://timebeat.com/)

6. Blockchain – example … Confirm that a particular document existed at a particular time (proof of contents, copyright etc.) + a secure time stamp is created

6. Blockchain – example …

6. Blockchain – example … President of the Association of Catalan Archivists and Vice-president of the Croatian Archival Society get blockchained (this morning)

6. Blockchain … The chain is formed of the linked blocks Each additional block reinforces the preceding ones Any attempt to modify a block will invalidate subsequent blocks and will be detected Even authorized changes are virtually impossible […] X X X X X X X X

6. Blockchain … Document verification the distributed ledger can be updated with a document only if qualified majority of participating nodes agree it can be verified as a document  the chain contains proof that a document was part of original set of documents the chain was built upon […]

6. Blockchain … Public blockchain Private blockchain Anyone can freely write data without permission granted by any authority Only known and trusted (authorized by an authority) participants can freely write data No point of control (except initial authorization) (Relative) anonymity No anonymity Examples: Bitcoin, Ethereum Example: a group of partnering archives

6. Blockchain – implementation possibility Connecting a document management system with the blockchain via a blockchain aggregator Shared ledger (TrustChain©) timestamped block verification time Blockchain aggregator sealed block Publication channels Clock document hash receipt (chain of proof) Document creators DMS Document users

6. Blockchain – research On-going research as part of the InterPARES Trust (http://interparestrust.org) project: Model for Preservation of Trustworthiness of the Digitally Signed, Timestamped and/or Sealed Digital Records (TRUSTER Preservation Model) investigating the possibilities of using linking based timestamping and blockchain technology for long-term preservation of digitally signed records developing a TrustChain© model

7. Conclusion Blockchain can be used in document management to confirm integrity of a document confirm that a document was existing or created at a certain point in time (i.e. not after it was timestamped and registered in the blockchain) confirm sequence of documents thus strengthening document versioning support/enhance non-repudiation of a document improve the validation possibilities of digitally signed documents/records during the long-term preservation

7. Conclusion … ISO/TC 307 – Blockchain and electronic distributed ledger technologies new standard being developed Document management, recordkeeping and archiving in the digital age archivists need to understand new technologies in order to be able to evaluate their impact, and include them in archival processes Act proactively and be able to offer professional opinions! Embracing new technologies will result in very personal gains for archivists.

INFuture2017:  Integrating ICT in Society Zagreb, 8-10 November 2017 The Westin Zagreb Hotel http://infoz.ffzg.hr/INFuture/

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New Technologies applicable to Document Management: Blockchain THANK YOU! New Technologies applicable to Document Management: Blockchain Hrvoje Stancic, Ph.D., assoc. prof. Faculty of Humanities and Social Sciences University of Zagreb, Croatia hstancic@ffzg.hr