September 20, 2016

Accenture Debuts Prototype of ‘Editable’ Blockchain for Enterprise and Permissioned Systems

Invention addresses blockchain ‘immutability’ challenges for permissioned systems, including the legal ‘right to be forgotten,’ human error, illegal actions

Co-developers Accenture and Dr. Giuseppe Ateniese register U.S. and E.U. patents

NEW YORK, LONDON, HONG KONG; Sept. 20, 2016 – Accenture (NYSE: ACN) has created a prototype of a new capability that enables blockchain technology to be edited under extraordinary circumstances to resolve human errors, accommodate legal and regulatory requirements, and address mischief and other issues, while preserving key cryptographic features. The prototype represents a significant breakthrough for enterprise uses of blockchain technology particularly in banking, insurance and capital markets.

The invention is designed for “permissioned” blockchain systems, which are managed by designated administrators under agreed governance rules. The invention is not designed for “permissionless” systems, like the cryptocurrency system supporting Bitcoin, which is open and decentralized and where the absence of a single governing authority makes absolutely permanent, or “immutable,” recordkeeping vital.

“As we focus on new uses for blockchain technology beyond the realm of cryptocurrency, absolute immutability will become both a virtue and a vice,” said Richard Lumb, group chief executive – Financial Services at Accenture. “For decentralized cryptocurrency systems, such permanent accounting has been crucial in building trust and faith among participants. But for financial services institutions faced with a myriad of risk and regulatory requirements, absolute immutability is a potential roadblock. Our invention strikes a balance for enterprise use that preserves the fundamental value of the technology while enabling enterprise adoption.”

How the Editable Blockchain Works
The invention provides an alternative to existing blockchain technology. Blockchains are immutable to users of the system but, when necessary, designated administrators acting on agreed rules of governance can edit, rewrite or remove blocks of information without breaking the chain. It does this by using a new variation of what is known as the “chameleon” hash function, which can recreate algorithms that link two separate blocks through the use of secure private keys.

The invention also offers a capability where any edit made to a block leaves an immutable “scar” to indicate that the block was altered. Accenture and co-developer Dr. Giuseppe Ateniese have filed patent applications for the invention in the United States (US 15/253,997) and the European Union (EP 164 250 86.2).

Accenture will present the invention next week at Sibos 2016 (Booth C69) in Geneva, Switzerland.

Accenture has created a prototype of an editable blockchain capability for permissioned systems based on a modified chameleon hash function developed with Dr. Giuseppe Ateniese

Real-World Demand
The need for redaction capabilities in permissioned blockchain systems recently surfaced when tens of millions of dollars were reported stolen from another digital currency system due to coding problems in a ‘smart contract’ – a software program that resides on blockchains and automatically executes transactions when pre-agreed events take place.

“As blockchain solutions gain momentum in financial services and other industries, more and more real-world situations will emerge where information on blockchains simply needs to be modified or removed,” said David Treat, managing director of Accenture’s capital markets blockchain practice. “Our solution makes it possible to deal with situations in a predictable fashion when things go wrong and to meet new and changing regulatory and legal requirements, like the ‘right to be forgotten’ and other data-privacy and retention rules. An editable form of blockchain will make the technology more practical and useful for enterprise systems and accelerate its adoption. It combines the confidence that comes from immutability with the pragmatism required in an imperfect world.”

“The clever work of the bitcoin creators and leaps of progress in applied cryptographic research are opening the door to bold new uses of blockchain,” said Dr. Giuseppe Ateniese, a leading cryptographer and professor of computer science at The Stevens Institute of Technology. “By modifying the traditional ‘chameleon hash’ function we can preserve the strength of the original blockchain while making it even more useful. Unlike a traditional database, our solution is compatible with current blockchain frameworks and works in a decentralized and accountable environment.”

Further detail on the need for an editable blockchain is available in Accenture’s newly published report “Editing the Uneditable Blockchain: Why distributed ledger technology must adapt to an imperfect world.”

Editor’s note
With conventional blockchain technology, if someone attempts to make a change to a block, they “break the math,” or chain of algorithms, that holds the blocks of information together. Unless a sufficient number of participants accept the change, the system essentially rejects it, leaving the blockchain intact and creating an evidence-trail of tampering. If a sufficient number of participants agree to the change, a fork can be added, with one prong ending on or diverging from the faulty block and another prong continuing onward from the corrected block. After a block has been corrected all subsequent blocks must be reconstructed, which can be disruptive and costly and, in some cases, practically impossible.

About Accenture
Accenture is a leading global professional services company, providing a broad range of services and solutions in strategy, consulting, digital, technology and operations. Combining unmatched experience and specialized skills across more than 40 industries and all business functions – underpinned by the world’s largest delivery network – Accenture works at the intersection of business and technology to help clients improve their performance and create sustainable value for their stakeholders. With more than 375,000 people serving clients in more than 120 countries, Accenture drives innovation to improve the way the world works and lives. Visit us at

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