Quantum Computing Breaks 6-Bit Elliptic Curve Signature
On September 2, Steve Tippeconnic, developer and quantum computing specialist at IBM, published a study where he claims that he managed to break a 6-bit elliptic curve (ECC)-based digital signature.
Although this is a much smaller key size than that used by current systems such as Bitcoin (256 bits), the experiment represents a relevant advance by demonstrating that a quantum attack using variants of the Shor algorithm could be applied.
In Tippeconnic’s own words, “although the size of the key is small, the result demonstrates the feasibility of a Shor-style quantum attack on real hardware.”
A quantum attack in practice
To carry out the “attack”, the developer used the 133-qubit IBM_torino processor.
The goal of the experiment was to find a secret key called “k” from a public equation used in elliptic curve cryptography (Q = kP).
You can imagine it as if someone reached a destination point on a map, but without revealing the exact distance they traveled to reach it. The task of the experiment was precisely to deduce that hidden distance from the final visible position.
As Tippeconnic explained, the quantum circuit generated special mathematical interferences that allowed us to get closer to this hidden value.
To achieve this, the system was run 16,384 times, as if a die was rolled thousands of times to observe what patterns are repeated. The result was a drawing on the “screen” of the Quantum Fourier Transform (QFT), a tool that translates signals into frequencies, similar to breaking down a song into its distinct notes.
Although the circuit was extremely complex (with more than 340,000 steps chained together), the results showed a clear pattern. After applying additional analysis with classical methods, it was discovered that the secret key was the number 42, one of the values that appeared most relevant in the results.
The importance of the experiment does not lie in the magnitude of the broken key (barely 6 bits, an inoperative size in any real application), but in the proof that a quantum attack can materialize in practice.
These 256-bit Bitcoin keys are, for now, impossible to breach using classical computing. However, IBM’s work reflects that, as quantum computing becomes stronger, current cryptographic schemes could be put at risk.
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