Zcash Advances Quantum Readiness With Ironwood’s Shielded Notes Upgrade

TLDR: Zcash’s Ironwood upgrade activated on July 28, 2026, at block 3,428,143, opening a new shielded pool. Ironwood notes use plaintext marker 0x03, replacing Orchard’s 0x02 format to prepare for future recovery. ZIP 2005 reserves marker 0x0A for PRF-expand, but it does not make shielded transactions quantum-resistant. Recovery remains unfinished, while Sprout, Sapling and Orchard funds lack the same planned protection. Zcash’s push toward quantum preparedness has moved from theory to how shielded funds are recorded. Its Ironwood upgrade, activated July 28, 2026, introduced notes designed to support recovery if current cryptographic protections fail.