Did Someone Really Break Bitcoin’s Encryption? Here’s The Truth About What Happened

The latest threat to Bitcoin’s cryptography is quantum computing. A researcher called Giancarlo Lelli has now won a one Bitcoin prize for using quantum hardware to crack a small cryptographic key linked to the same family of mathematics that protects Bitcoin. 

This sounds terrifying at first glance, as it threatens the future of billions worth of Bitcoin. However, it also needs careful handling, because the truth is more complicated than breaking Bitcoin’s encryption.

Researcher Makes Successful Attack On Elliptic Curve Cryptography

The event came from Project Eleven’s Q-Day Prize, which was awarded to independent researcher Giancarlo Lelli. Lelli used publicly available quantum hardware to break a 15-bit elliptic curve cryptography key, using a variant of Shor’s algorithm to derive a private key from a public one. 

The previous public quantum attack record was a 6-bit cryptographic key in September 2025, which means Lelli’s 15-bit result extends the record by a factor of 512 in complexity. 

Interestingly, the hardware involved was not a classified government system or a private supercomputer. Lelli ran the attack on a publicly accessible quantum device with about 70 qubits, completing it in only 45 minutes.

The implications tie directly into how BTC’s security model is structured. That matters because Bitcoin relies on the same elliptic curve cryptography that was broken. 

According to Project Eleven, an estimated 6.9 million BTC valued at about $520 billion, are held in addresses where the public keys have already been revealed on-chain. This includes the roughly 1.1 million BTC attributed to Bitcoin creator Satoshi Nakamoto. Advances like these raise concerns about how soon such holdings could become vulnerable, bringing forward timelines to when they can be under threat from bad actors.

Is Bitcoin’s Encryption Broken?

A 512x jump in seven months is the kind of progress curve that tends to get people’s attention. Progress at that pace suggests the computational threshold required to challenge BTC may be very close. However, Bitcoin does not use 15-bit keys. Bitcoin’s real security operates at a 256-bit scale, which is vastly beyond what was broken in this experiment.

Project Eleven CEO Alex Pruden noted that “The resource requirements for this type of attack keep dropping, and the barrier to running it in practice is dropping with them.”

Still, theoretical resource estimates for a full 256-bit attack have fallen massively over the past year. Google’s April 2026 whitepaper put the requirement at under 500,000 physical qubits. A subsequent paper from Caltech and Oratomic brought that figure as low as 10,000 qubits in a neutral-atom architecture. 

The quantum threat does not mean every Bitcoin wallet is equally vulnerable. The most discussed risk involves wallets whose public keys have already been exposed on-chain. Recent developments have given rise to the concept of “harvest now, decrypt later,” where bad actors are compiling public keys and waiting for future quantum computers to catch up.