Project Eleven, a post-quantum cryptography startup focused on safeguarding digital assets, has raised $20m in a Series A round.
The round was led by Castle Island Ventures, with participation from Coinbase Ventures, Fin Capital, Variant, Quantonation, Nebular, Formation, Lattice Fund, Satstreet Ventures, Nascent Ventures and Balaji Srinivasan. It also reported continued investment from Variant, Quantonation, Nebular and Formation.
Project Eleven is building tools designed to help major digital assets transition away from cryptography that could be broken by a future fault-tolerant quantum computer capable of running Shor’s algorithm, which could allow private keys to be derived from public keys. The company argues that, without preparation, the concept of on-chain “digital ownership” could be undermined as quantum capabilities advance.
The business said the new funding will support its efforts to accelerate what it describes as a new suite of products aimed at securing blockchain networks ahead of “Q-Day” — the point at which quantum systems become cryptographically relevant.
The company positioned 2025 as a turning point for quantum computing, citing demonstrations of below-threshold quantum error correction and the emergence of the “largest quantum machine ever built”. It also said resource estimates for running Shor’s algorithm fell by a factor of 20 during 2025, which it views as a sign that the industry’s timeline assumptions are shifting quickly.
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