However, the primary problem with blockchains is that same immutability. Once something is stored in a blockchain, it stays there forever. Forever is a very long time, and storing data forever creates its own problems.
For public blockchains like the one used by Bitcoin, storage costs are not negligible. Each transaction on that blockchain must include a transaction fee that’s supposed to offset the cost of storing that record forever. This leads to scalability problems: since each transaction costs money, it’s not feasible to transact on a public blockchain on an industrial scale. For private blockchains, this is not really a problem because so few copies of the database exist, and they might not even have to live for that long. But a large number of copies is part of the security and reliability of blockchains, so there is a tradeoff between cost and security.
iDefendo’s technology was designed to mitigate these problems and make it possible to use public blockchains on an industrial scale with predictable costs that scale nonlinearly with the number of transactions. We automatically batch transactions so that an arbitrary number of transactions within our system can share a single public blockchain transaction. This reduces costs without sacrificing any of the security and integrity offered by the large, public blockchains that are in widespread use, to which we connect.
At the core of our technology is something we call a Digital Witness. A Digital Witness interlocks three pieces of information that we call WHAT, WHEN, and WHO. WHAT uniquely identifies some data, such as a file, a database record, or a transaction identifier. WHEN is the date and time when the Digital Witness saw the information, and WHO is a signature that identifies the person or company who created the Digital Witness.
Information is often sensitive, and it might be subject to regulatory requirements. That’s why we’ve designed our technology in such a way that we do not have to see your information. The information we require as WHAT can be calculated within your systems, so no sensitive information ever leaves your secure environment. We see only the calculated cryptographic hash – like a digital fingerprint – that's created using a one-way function, and these hashes convey no information about the content they represent.
Each Digital Witness is self-validating, meaning that as long as you have access to the original information that made up WHAT, you can prove that WHEN and WHO are also unchanged since the Digital Witness was created.
The last step is to lock the WHEN part of the Digital Witness to a reliable time stamp, and that’s where our batched blockchain transactions come in. All Digital Witnesses in the system created during a specific period of time are added to a so-called hash tree, and the root of that tree is used to create a transaction in one or more public blockchains. A user can also elect to have each Digital Witness create a transaction on one or more private blockchains.
A Timeline is like a small blockchain in itself. It comprises a number of Digital Witnesses that are chained together so that the latest link added always points back to the preceding one. A Timeline can thus be used to document a multistep process that has a time dimension, where step A can be proved to have been performed before step B and so on. If an attempt is made to either remove a link in the chain or insert one at any position other than last, the chain will immediately be mathematically invalid and the attempt will thus be clearly detectable.
The Evidence Engine is the name of the platform that we have built on top of the Digital Witnesses and the Timelines. On the platform, developers can create apps that leverage the power of the underlying technology. An app can have a user interface and be used by humans, but it can also be fully automated and perform background tasks. Examples of the former category are our pre-built apps Transfer and Vault, and an example of the latter is an app that automatically creates Digital Witnesses and Timelines for every new and changed file in a connected Dropbox account, allowing users to prove when each version of files in their Dropbox was created and edited.
A blockchain can be compared to a distributed ledger that provides a trustworthy, immutable record of information without the need for verification by a centralized authority. A blockchain is often called trustless, since it takes away the need for third parties to be involved in transactions. It does so by building a database of entries (each of which is built from a preceding block of information and stored as a copy) that is secured by a complex mathematical algorithm. Each party owns an identical copy of the record, which is automatically updated when any change is made to it. This makes it extremely difficult for anyone to create fraudulent transactions or alter existing transactions. Since you can store any kind of information on the blockchain, it is applicable to and usable in a wide range of sectors.
Blockchains can be public and open (permissionless) or structured within a private group (permissioned). The blockchain functionality that many commercial actors have chosen to work with is permissioned blockchains, since only preapproved participants may join them and take part of the information that is shared.