By Ken Cottrill, Co-Founder and Research Principal
The words “blockchain” and “immutable” often appear in close proximity to each other, because blockchains are supposed to be paragons of immutability.
But what does that really mean?
The Meriam-Webster definition of immutable is: “not capable of or susceptible to change.”
This definition could apply to:
Does it apply to blockchain technology?
The answer is yes. More or less.
Blockchains are certainly not susceptible to change. Once a transaction has been validated and accepted, cryptography makes it very difficult to alter the entry. As the blockchain matures and more “blocks” are added, it becomes even tougher to meddle with the contents.
But it’s not impossible. For example, last year Accenture caused a stir among blockchain aficionados when the consulting firm announced that it created a prototype edit function for blockchains. The chameleon hash (sounds like a new Asian dish) function is meant to be used when a blockchain “has to be edited under extraordinary circumstances.”
Purists claim that inserting trap doors in this seemingly impregnable technology defeats the object of the exercise. And they have a point.
In the commercial world, however, many enterprises are nervous about the idea of an unalterable database. For instance, there are heavily regulated financial services companies that want the leeway to edit a blockchain in response to regulatory change. They argue that such actions will be truly exceptional, and typically apply to permissioned blockchain systems that are managed by administrators.
But even where there are no surreptitious passageways into a ledger, users can still band together to storm the ramparts and change the records if they have a mind to.
Similarly, if a powerful organization such as a government with almost unlimited financial and computing resources wanted to break into a blockchain – whether permissioned or not – it probably could.
Does this mean that immutability is just empty jargon, and in the real world blockchains are just as vulnerable to mischievous editing as any other database?
The key phrase here is “real world.” To all intents and purposes everyday blockchains can be considered tamper-proof. The amount of effort and resources needed to infiltrate them is enough to deter most mischief makers. Besides, up until now, the technology appears to be unassailable alongside the hack-ridden databases and information exchanges currently in common use.
Will the technology’s defenses remain that way as more bad guys test the walls? That’s anyone’s guess.
And there are some privacy challenges to overcome. For instance, in Europe there is a “right to be forgotten” ruling that basically allows individuals who believe that they are being misrepresented by search engine results to demand redress. The incorrect details could be decoupled from searches, for instance.
In today’s hectic world, there are times when a right to be forgotten seems like the best idea since the zipper fastener. But it runs counter to the unalterable nature of blockchain systems.
Such issues need to be addressed, but not to the point where we obsess over whether blockchains qualify as genuinely immutable. The technology is not like the laws of gravity; it is a human construct that hopefully delivers a better way to do business.
And it will change over time. Innovation is not immutable.
For more information on the issue of blockchain immutability take a look at these blogs: