They invented a technological feature, called “traveling transactions, which relativizes the immutability of transactions in Ethereum accounting. This feature would apply to the so-called “smart transactions” behaving like a time machine, which goes back over the transactions and is able to make certain modifications to them. The whitepaper of this technology states that it is not capable of modifying the confirmed blocks of the accounting record on the chain. In other words, it is a myth that these time travels break the immutability of accounting. 

Anuj Das Gupta, one of the co-founders of Smart Transactions (stxn) and the person behind the “time machine,” said the following in an exclusive interview with a media outlet at a developer conference in Bangkok, Thailand: “We believe this is an important solution to the tension between flexibility and immutability when it comes to blockchains.” 

The developers of this technology comment that this function to reverse transactions will be more useful for users prone to making human errors when trading on cryptocurrency networks. 

Another area of ​​application for the time machine, Boris Mamlyuk says, is identifying malicious actors within applications that integrate traveling transactions : “If the application is misused, we can go back and recover the blockchain rewards that someone earned as a result of that misuse. So it’s a force multiplier. It opens up the utility.” 

Smart transactions would be like reversible emails 

According to the outlet, the stxn CEO compared the immutability of the blockchain to the early days of emailing in the late 20th century: once a message was sent, it was impossible to undo it. Today, however, it is possible to immediately undo sending an email with a single button. 

Smart transactions aim to do the same thing as modern reversible emails, but in so-called Web3, according to Das Gupta. “It allows us to travel back and forth in time in the transaction sequence flow, which opens up a lot more utility, just like that unsend button,” he explained. 

The creators of stxn compare the irreversibility of emails, which was a design limitation, to the immutability of Bitcoin and the various . networks . However, Satoshi Nakamoto, the creator of the network that inspired the creation of other networks that followed, considered complete immutability to be the most secure and radical way to eradicate the need for trust between participants. And he employed complete immutability on the Bitcoin chain not only as a technical decision of his P2P payment system on the Internet, but as one of its main properties, as a foundation stone of the Bitcoin building.  

There is therefore a need for an electronic payment system based on cryptographic proof rather than trust, allowing two willing parties to transact directly with each other, without the need for a trusted third party. If transactions are computationally impossible to reverse, they will protect sellers from fraud, and any escrow mechanism can be easily implemented to protect the buyer. 

Satoshi Nakamoto, creator of Bitcoin 

Confirmed blocks are untouchable, according to stxn 

According to Smart Transactions ’ whitepaper, their time travel system does not modify the past or confirmed transactions on the chain. “Changing the past should be prohibited at all costs,” they say.  

Since the past represents confirmed transactions, we would have to be able to reorder confirmed blocks, which is definitely not conceptually possible and remains technically inadmissible from what we understand and how we design our time travel infrastructure.

stxn, creator of “traveling transactions”. 

By time travel, the developers are referring “solely to the way time might be represented in the before-after mode (i.e., timing), and not as the mode of temporality (past-present-future).” 

Technically speaking, this means that the time element of smart transactions “should be modeled as a data structure of transitions/events, such that they are arranged in a before-after relationship.” This results in an organization according to “when” each smart transaction exists waiting for confirmation. 

At stxn they reaffirm that no transaction can travel beyond the current block, and that travelling transactions do not break the immutability of the chain. They comment that, however, a transaction can “advance to a block that has not been confirmed, either the current one in the middle of its production or one that will come later, causing the transaction to remain in a waiting station on the chain ready to be picked up.” 

Since most networks import the Ethereum virtual machine and its development pipelines, it is possible that “time travel” functionality will be transferred to other networks in the cryptocurrency ecosystem.