How to build private smart contracts via : - zkSNARK: State is commitments, a single prover computes on plaintext and posts a zkSNARK, no global decryption or access control. - coSNARK: State is commitments, computation is off-chain via MPC so no single server sees the full witness, still no global decryption or access control. - TEE: State is ciphertext outside and plaintext inside the enclave, computation and policy gated decryption run inside a remotely attested enclave, relying on hardware/attestation integrity. - FHE: State is ciphertext under a common FHE key, anyone can homomorphically evaluate with on-chain verification, decryption is policy gated by a threshold committee (collusion risk). - iO: State is ciphertext and compute is homomorphic, a public obfuscated decryptor enforces decryption policy without a live keyholder (no collusion risk).

got the idea to write this while watching the Jigsaw talk at SBC () which a coSNARK-based approach to private smart contracts.