Disclosure: The opinions voiced here are solely those of the author and do not reflect the views or opinions of the editorial team.
As the ongoing scandal unfolds and experts assess the extent to which senior officials have jeopardized US national security through the leak of that Signal chat, along with the embarrassment stemming from their contentious follow-up comments, I’d like to delve into one specific incident from this narrative.
Initially, the White House claimed that the chat never existed. However, as evidence mounted, they changed their stance, asserting that the chat contained no classified information of national security relevance. What evidence can journalist Jeffrey Goldberg provide in the wake of that chat? Furthermore, the messages in the chat were programmed to erase themselves after a certain time. Imagine a courtroom environment where the evidence presented consists solely of screenshots—almost no evidence at all, as such documentation is nearly impossible to authenticate.
The solution is straightforward—if the journalist had responsibly preserved his evidence. He could validate that he had access to sensitive information at a time when he should not have, by disclosing cryptographic hash sums of that data. If he had not been part of the chat, he would not have known the timing and details of the planned strike in Yemen, including the target, among other specifics. While some details may eventually be released, they would not have been publicly known during the chat—correct?
The remedy lies in a cryptographic technique called proof of existence without disclosure. This method has two fundamental components: cryptographic hashes and trustworthy timestamps. This can be achieved on the blockchain either manually—if one is familiar with the process—or through various applications and services that provide blockchain-based timestamping proofs.
Here’s how it functions: you draft a message (for instance, by copying text from the chat), generate a hash of that message, publish it on a blockchain, and retain the private key associated with the address you used to make that publication. Later, you will require this private key to demonstrate that it was indeed your address (that is, you personally) that published the hash, thereby confirming your awareness of the original message at that moment. Although a social media account could serve a similar purpose, it is essential to remember that social networks are centralized platforms—vulnerable and, unlike blockchains, not permanent.
Thus, this serves as a valuable note for journalists who may one day find themselves needing to validate the existence of a fact while keeping its contents confidential.
This procedure produces an indisputable, timestamped record that verifies a specific original message existed and was acknowledged by the publisher at the time the blockchain transaction was validated—all while keeping the content private until the journalist opts to disclose it.