Nethermind optimized Noir UltraHonk verification for Soroban by moving cryptographic operations from guest WASM to Protocol 25/26 native host functions. The result: 64% reduction in CPU instructions, verification fees cut from 0.23 to 0.09 XLM, and shielded-pool applications now feasible.
Noir UltraHonk verification on Soroban was possible but expensive: the baseline verifier consumed 224.8 million CPU instructions (56% of the 400M limit), leaving little room for application logic. Nethermind reduced that cost by 64% through three optimization phases: migrating scalar-field arithmetic to Protocol 25 BN254 host functions, cleaning up hot-path overhead in the verifier logic, and replacing a hand-rolled G1 multi-scalar multiplication loop with a native host call (CAP-0080). The final verifier uses roughly 80M instructions, leaving 80% of the transaction budget for shielded pools, privacy applications, or other Noir-based contracts. On Stellar Testnet, a shielded-pool proof verification costs 0.01242 XLM.