- Ripple’s roadmap, published April 20 by senior director of engineering Ayo Akinyele, schedules candidate post-quantum signature schemes to run alongside elliptic-curve signatures on the XRP Ledger’s Devnet in the second half of 2026.
- The plan targets a network-wide amendment and full transition to post-quantum cryptography no later than 2028, with partner Project Eleven building a hybrid signing prototype and a quantum-safe custody wallet.
- A “Q-Day” contingency would force what Ripple calls a hard shift, with classical signatures no longer accepted by the network and all funds moved to quantum-safe accounts.
Ripple is working through a four-phase plan to ready the XRP Ledger (XRPL) for quantum computers, set out in an April 20 roadmap that puts candidate quantum-resistant signature schemes on the network’s Devnet in the second half of 2026 and targets a full transition no later than 2028.
Ripple senior director of engineering Ayo Akinyele published the roadmap three weeks after Google Quantum AI reported that the elliptic-curve cryptography securing crypto wallets could be broken by quantum circuits needing fewer than 1,450 logical qubits, running on fewer than 500,000 physical qubits, about a 20-fold cut to earlier resource estimates.
“The threat has moved from theoretical to credible, and preparation timelines now matter”, the Ripple post stated.
Akinyele flagged the exposure directly: “Every time an account signs a transaction, its public key becomes visible onchain, and in a post-quantum world, that exposure could eventually be exploited.”
The post also cited the risk researchers call harvest now, decrypt later, where attackers collect visible on-chain key data today and wait for quantum hardware capable of cracking it.
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Four Phases Ending in 2028
Ripple spent the first half of 2026 on a network-wide quantum risk assessment and on testing signature schemes recommended by NIST, the US standards body that finalised its first three post-quantum algorithms in August 2024.
The current phase runs candidate schemes beside existing elliptic-curve signatures on Devnet, and the final phase would propose an amendment for native post-quantum cryptography, requiring coordination across XRPL’s independent validators.
Ripple confirmed it is working with post-quantum security firm Project Eleven on a hybrid signing proof of concept, validator-level testing, Devnet benchmarking and a quantum-safe custody wallet prototype.
The company stated it is designing for cryptographic agility, with support for multiple NIST-standardised algorithms so the ledger can adapt as the post-quantum field matures.
Emergency Path if Q-Day Comes Early
Phase one of the roadmap is a standing contingency for a sudden break in classical cryptography.
In that scenario, Ripple stated, “classical public-key signature standards are no longer accepted by the network, and funds must move to post-quantum secure accounts”, with post-quantum zero-knowledge proofs under study so owners can prove control of existing keys without exposing them.
XRPL already supports native key rotation, letting users retire vulnerable keys without changing accounts, though Ripple noted these building blocks “are not post-quantum solutions on their own”.
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