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Zama Protocol Change Log

This page tracks upcoming and ongoing milestones for the Zama Protocol and related releases. It updates as new versions are planned and deployed.

Zama Protocol status

Deployed and planned FHEVM versions on the Testnet and Mainnet.

Status
Version
Details

Testnet

FHEVM v0.13

Change log ↗

Mainnet

FHEVM v0.11

Change log ↗

See the full version status in the Zama Protocol Version Dashboard.

Product updates

FHEVM

FHEVM v0.13 — June 2026

Highlights

The v0.13 release strengthens multichain support, introduces a redesigned developer SDK, and improves coprocessor consensus monitoring:

  • Improved Multichain support, building on the multi-chain foundation introduced in v0.12 with per-chain worker isolation and simplified host chain configuration.

  • New @fhevm/sdk npm package with a major refactor of the relayer SDK.

  • New FHE operations: FHE.sum and FHE.isIn for aggregation and membership checks on encrypted values.

  • All-contracts delegation: delegating to the 0xffffffffffffffffffffffffffffffffffffffff sentinel address grants a user delegation rights over all contracts.

  • Coprocessor consensus drift monitoring, with metrics and logs that can be used for alerting.

  • tfhe-rs upgraded to v1.6.1 across the Coprocessor and KMS.

New features

  • FHE.sum (Copro): sums a list of encrypted values in a single FHE operation.

  • FHE.isIn (Copro): checks whether an encrypted value belongs to a given set.

  • All-contracts delegation (Copro, KMS, Devex): users can delegate decryption rights across all contracts at once by delegating the 0xffffffffffffffffffffffffffffffffffffffff contract address. See RFC 017.

  • @fhevm/sdk npm package (Devex): new SDK package replacing the previous relayer SDK structure, with a major refactor.

  • Coprocessor consensus drift monitoring (Copro): detects anomalous coprocessor consensus drift.

  • Generic event listener (Copro, Gateway): a generic event listener is now integrated in the Coprocessor.

  • AI skills repository (Devex): a new public repository of AI agent skills for building on FHEVM — zama-ai/skills.

Improvements

  • Multichain hardening (Copro): host chains are now seeded declaratively with per-chain worker isolation, the host chain ID is derived from ciphertext handles instead of static gw-listener configuration, and Helm charts are updated for multi-coprocessor and multichain deployments.

  • IAM authentication for the Coprocessor RDS (Copro): database access now supports IAM-based authentication instead of static credentials.

  • Improved consensus reconciliation (Copro): better reconciliation logic for multi-coprocessor consensus.

  • KMS context and extra_data verification (KMS, Gateway, Copro): context and extra_data are now verified on all KMS endpoints.

  • tfhe-rs upgraded to v1.6.1 (Copro, KMS).

  • Extensive end-to-end test suite (Devex): broader e2e coverage across input, compute, and decryption flows.

FHEVM

FHEVM v0.12 — April 2026

Highlights

The v0.12 release brings multi-chain support, stronger consensus, and tighter resource controls to the Zama Protocol:

  • Multi-chain coprocessor support and multi-coprocessor consensus with deterministic ciphertext re-randomisation, enabling coprocessors to converge on identical FHE results across chains.

  • KMS context-aware decryptions introducing epoch IDs and context-state validation across the Gateway, KMS connector, and host contracts.

  • Per-block HCU metering on the host with configurable per-block, per-transaction, and per-depth Homomorphic Compute Unit limits, plus a whitelist for privileged callers.

  • Simplified ACL (v2) replacing the MultichainACL contract suite with a single access-control flow on the host chain.

  • Compressed key generation on GPU in the KMS, lowering key-generation overhead for GPU-backed deployments.

New features

  • Multi-chain coprocessor support (Copro): coprocessors can now serve multiple host chains in a single deployment.

  • Multi-coprocessor consensus (Copro): independent coprocessors converge on identical FHE results, with deterministic re-randomisation as the foundation.

  • KMS context-aware decryptions (Gateway, KMS, Host contracts): a new "KMS context" system adds epoch IDs and context state to decryption operations. Decryption requests carry context-aware extraData, and the KMS connector validates context state via a new kms_context table and Ethereum listener.

  • Per-block HCU limits (Host contracts): a new HCULimit contract enforces configurable per-block, per-transaction, and per-transaction-depth Homomorphic Compute Unit limits, with a whitelist mechanism for privileged callers to bypass block limits.

  • Compressed key generation on GPU (KMS).

  • Coprocessor state revert tooling (Copro): new revert_coprocessor_db_state.sql script, packaged in the db-migration Docker image, that can revert a coprocessor to a previous block number.

  • Gateway ciphertext drift detection (Gateway): opt-in detection comparing local ciphertext digests against on-chain consensus, enabled via --ciphertext-commits-address.

  • Library-Solidity additions: FHE.isPublicDecryptionResultValid view function for on-chain decryption signature validation; FHE.fromExternal returns a trivial-encrypt of 0 for uninitialized handles instead of reverting.

  • relayer-sdk v0.5.x (Devex): new extraData parameter on the relayer SDK.

Improvements

  • ACL simplification (v2) (Host contracts): the MultichainACL contract suite is removed; access control is consolidated on the host chain with simpler validation.

  • New handle format (Host contracts): handle hashing now includes a FHE_comp domain separator and the previous block hash + timestamp, strengthening uniqueness across chains and time.

  • Per-FHE-operation re-randomisation (Copro): ciphertext inputs are re-randomised per FHE operation using a deterministic seed derived from input ciphertexts and operator.

  • Re-randomisation of input ciphertexts before first compression (Copro).

  • KMS-connector switched to eth_getLogs (KMS): replaces subscription-based event listening with batched database insertion.

  • tfhe-rs upgraded to v1.5.4 (Copro/MPC).

  • Contract upgrade version check CI: a new workflow enforces that REINITIALIZER_VERSION and version constants are bumped when contract bytecode changes.

  • ECDSA.sol renamed to FhevmECDSA.sol to fix naming conflicts.

Breaking changes

  • MultichainACL contracts deleted: MultichainACL.sol, MultichainACLChecks.sol, and IMultichainACL.sol are removed entirely.

  • isUserDecryptionReady signature changed: the address userAddress parameter was removed. The old signature is preserved via a backward-compatibility overload but is deprecated.

  • New handle format: FHEVMExecutor handle hashing now prepends COMPUTATION_DOMAIN_SEPARATOR ("FHE_comp") and appends blockhash(block.number-1) + block.timestamp.

  • HCULimit contract required: FHEVMExecutor REINITIALIZER_VERSION bumped to 3; initialization requires hcuCapPerBlock, maxHCUDepthPerTx, and maxHCUPerTx. Integrators must sync to get whitelisted contracts.

  • ACL REINITIALIZER_VERSION bumped to 4: ExpirationDateBeforeOneHour error replaced by ExpirationDateInThePast. Validation now only checks expirationDate > block.timestamp.

  • KMSVerifier upgraded for context-aware decryption with epoch / context support.

  • ECDSA.sol renamed to FhevmECDSA.sol: import path changes from cryptography/ECDSA.sol to cryptography/FhevmECDSA.sol; library renamed from ECDSA to FhevmECDSA.

  • Coprocessor: tenants table removed from the DB; legacy tfhe-worker gRPC endpoint removed.

Bug fixes

  • Backport of prepareUpgrade flows to the 0.12.x line.

  • Reduced coprocessor migration lock time during the 0.12 migration.

  • Coprocessor no longer reads key blobs from the database on key cache hits.

Resources

FHEVM

FHEVM v0.11 — February 2026

This release brings major performance and security improvements to the Zama Protocol.

Highlights

  • tfhe-rs v1.5.0 upgrade across Coprocessor and KMS for improved FHE performance

  • ACL checks on host chain for direct access control enforcement through the relayer and KMS connector

  • Delegated decryption with a complete end-to-end flow

  • FHE statistics for TFHE-rs for better observability into Coprocessor FHE operations

New features

  • GPU acceleration: Optional GPU backends for ZK proof verification, Switch-and-Squash (SnS), and re-randomization. CPU-only deployments remain fully supported.

  • Delegated decryption: Complete end-to-end support for delegated user decryption, allowing authorized addresses to decrypt on behalf of users.

  • Operator staking system: New ERC-4626-based staking contracts with UUPS upgradeability, permit support, and Operator Rewarder contracts for fee management.

  • Confidential Tokens Registry: Added a Confidential Tokens Registry and ERC-7984 upgradeable wrapper contracts for encrypted token assets.

  • CLI tool: Added a new command-line tool for common FHEVM workflows.

  • BNB chain support: Added configurations for BNB chain deployments.

Improvements

  • tfhe-rs upgrade to v1.5.0: Updated across the Coprocessor and KMS, while FHE keys and serialized ciphertexts remain generally compatible.

  • ACL checks on host chain: Decryption ACL checks now run directly on the host chain through the relayer and KMS connector, reducing trust assumptions.

  • FHE statistics: Added FHE operation statistics and decryption performance metrics in the Coprocessor.

  • Dependence-chain processing: Improved the Coprocessor scheduler for better parallelism.

  • Host-listener poller mode: Added an alternative polling mode that replaces WebSocket-based event listening.

  • KMS garbage collection: Added garbage collection for KMS operations.

  • Database optimizations: Improved indexing for the ciphertext_digest table.

Fixes

  • Overflow prevention in the ProtocolStaking cooldown mechanism

  • ERC-4626 inflation attack mitigation using decimal offset

  • Better handling of cyclic dependence errors in the Coprocessor

  • Improved eth_getLogs timeout management in the host-listener

Resources

FHEVM

FHEVM v0.10 — October 2025

This preview introduces a dedicated payment contract in the Gateway and flexible delegation of decryption rights through smart contracts.

These changes improve fee management, access control, and the usability of encrypted operations.

Preview

  • Gateway payment contract for Coprocessor and KMS fee management

  • Delegation through smart contracts for controlled decryption access

  • Time-scoped permissions for temporary or session-based access

  • Contract-scoped permissions for stricter access control

New features

  • Gateway payment contract: Adds a dedicated payment contract within the Gateway to manage fees for Coprocessor and KMS operations, including input and decryption flows.

  • Delegation via smart contracts: Users can delegate decryption rights to other addresses with fine-grained control over scope and duration:

    • Explicit authorization for another address to generate EIP-712 signatures and run userDecrypt operations

    • Delegation validity defined by timestamp for temporary or session-based access

    • Delegation scoped to specific contract addresses for context-aware access control

Improvements

  • More flexible encrypted data access through delegation

  • More transparent fee management with a dedicated Gateway payment flow

Resources

FHEVM

FHEVM v0.9 — October 2025

This release adds new key generation capabilities, dynamic coprocessor management, and a redesigned decryption event flow.

These changes improve flexibility, scalability, and consensus handling while deprecating older event formats.

Breaking changes

The methods FHE.requestDecryption and FHE.setDecryptionOracle are now deprecated and must be removed.

Update your contracts to use the new decryption flow through the relayer.

Highlights

  • On-chain FHE key and CRS generation

  • Dynamic pauser management

  • Transaction input re-randomization

  • Redesigned user decryption events

  • Gateway API cleanup and renaming

New features

  • Support generation of FHE key and CRS on-chain:

    • Request FHE key and CRS generation directly through the Gateway.

    • New environment variables for gateway contracts:

      • KMS_GENERATION_THRESHOLD — threshold used to validate consensus on FHE key or CRS generation

      • KMS_NODE_STORAGE_URL_[0-N] — storage base URL for public materials for each KMS node

    • New environment variable for the coprocessor (gw-listener):

      • KMS_GENERATION_ADDRESS — address of the KMSGeneration gateway contract

    • New environment variable for the connector:

      • KMS_GENERATION_ADDRESS — address of the KMSGeneration gateway contract

Obsolete environment variables

These variables are no longer used:

  • FHE_PARAMS_NAME

  • FHE_PARAMS_DIGEST

  • New PauserSet immutable contract:

    • Host and Gateway contracts can now be paused by any address added in PauserSet.

    • New environment variables for gateway contracts:

      • NUM_PAUSERS — number of pauser addresses to add. Set this to n_kms + n_copro.

      • PAUSER_ADDRESS_[0-N] — pauser addresses

    • New environment variables for host contracts:

      • NUM_PAUSERS — number of pauser addresses to add. Set this to n_kms + n_copro.

      • PAUSER_ADDRESS_[0-N] — pauser addresses

Obsolete environment variable

This variable is no longer used:

  • PAUSER_ADDRESS

  • Re-randomization of transaction inputs:

    • All transaction inputs, including state inputs, are re-encrypted before FHE evaluation.

    • This provides sIND-CPAD security.

    • This feature is transparent to users.

Improvements

  • User decryption response:

    • Encrypted shares and signatures are no longer aggregated on-chain in the Gateway.

    • Each KMS response now emits its own event.

    • New events in the Decryption contract:

      • UserDecryptionResponse(uint256 indexed decryptionId, uint256 indexShare, bytes userDecryptedShare, bytes signature, bytes extraData);

      • UserDecryptionResponseThresholdReached(uint256 indexed decryptionId);

Breaking changes

This event is deprecated from the Gateway Decryption contract:

  • PublicDecryptionResponse(uint256 indexed decryptionId, bytes decryptedResult, bytes[] signatures, bytes extraData)

  • User decryption request:

    • User EIP-712 signature verification is simplified in the Gateway Decryption contract.

Breaking changes

The uint256 contractsChainId field is no longer part of the UserDecryptRequestVerification struct used for EIP-712 signature verification.

  • Gateway contract renaming:

    • MultichainAcl is renamed to MultichainACL.

    • KmsManagement is renamed to KMSGeneration.

Breaking changes

These Gateway contracts are renamed:

  • MultichainAcl → MultichainACL

  • KmsManagement → KMSGeneration

These environment variables are renamed:

  • KMS_MANAGEMENT_ADDRESS → KMS_GENERATION_ADDRESS

  • KMS_CONNECTOR_KMS_MANAGEMENT_CONTRACT__ADDRESS → KMS_CONNECTOR_KMS_GENERATION_CONTRACT__ADDRESS

In the KMS Connector Helm chart values.yaml, this field is renamed:

  • kmsManagement → kmsGeneration

  • Gateway check functions replaced:

    • All external check... view functions are removed from the Gateway contracts.

    • Associated errors are moved to other contracts or removed.

    • Equivalent is... view functions now return a boolean instead of reverting.

Breaking changes

All check... view functions are removed from the Gateway contracts.

For example:

  • checkPublicDecryptAllowed is replaced by isPublicDecryptAllowed

  • PublicDecryptNotAllowed is moved to the Decryption contract

Resources

FHEVM

FHEVM v0.8 — September 2025

This release makes FHEVM more scalable, secure, and developer-friendly.

Highlights

  • New KMS connector for modular integration

  • Compressed ciphertexts for lighter payloads

  • Flexible extraData field for richer apps

  • Post-quantum ML-KEM512 for faster, smaller decrypts

  • Stronger chain resilience and ERC-7995 compliance

New features

  • New KMS connector: Added a new Key Management System connector to improve modularity and integration.

  • Compressed ciphertext support: Added support for compressed ciphertexts in both the SnS worker and KMS, reducing payload sizes.

  • Generic extraData field: Gateway functions, events, and signed structs now include a generic extraData field for extensibility and custom data support.

  • SepoliaConfig update: Added the protocolId() function to support protocol identification.

Improvements

  • ERC-7995 compatibility: Updated the Oracle callback interface for compliance, following ERC-7995.

  • Reduced user decrypt payload size: Migrated to ML-KEM512 for 128-bit equivalent post-quantum security. This reduces decrypt response sizes and allows more responses per block.

  • Host listener: Added reorganization handling in the host listener for stronger chain resilience.

  • Library storage layout: Adjusted the storage layout to align with the standard guidelines.

Breaking changes

Oracle callback function signature now requires this format:

function callbackExample(
  uint256 requestID,
  bytes memory cleartexts,
  bytes memory decryptionProof
) external;

Resources

FHEVM

FHEVM v0.7 — July 2025

This release introduces the first iteration of the Zama Protocol.

Highlights

  • Gateway is now a core component for protocol orchestration.

  • Coprocessor input verification is now enforced on the coprocessor side.

  • Decryption pipeline now prepares ciphertexts for decryption on coprocessors.

  • Solidity library is restructured to match the new protocol architecture.

Breaking changes

  • Renamed the library from TFHE to FHE

  • Introduced FHE.requestDecryption with support for msg.value, deprecating GatewayCaller

  • Removed ebytesXXX types

  • Replaced einput with externalEuintXXX, externalEbool, and externalEaddress

  • Introduced per-transaction operation limits, replacing the previous per-block limit

Resources

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