Protocol Alpha

This page contains all the relevant information for protocol Alpha, a development version of the Tezos protocol.

The code can be found in the src/proto_alpha directory of the master branch of Tezos.

This page documents the changes brought by Protocol Alpha with respect to Edo.

Baking Accounts

A new account type has been added to represent accounts managed by bakers. These accounts are Michelson smart contracts running a fixed multisig script. This feature lets bakers renew and split their consensus keys without moving to a new address and asking their delegators to follow. In addition to the usual internal operations, baking accounts can also emit baking operations such as proposing and voting for protocol amendments.

/!This is a breaking change, see the corresponding section in the TZIP.

Smart Contracts/Michelson

Increase max_operation_data_length to 32KB

The maximal size of operations is doubled. In particular this has the effect of slightly more than doubling the maximum size of a smart contract.

Depth-First Execution Order

The applied order of inter-contract calls emitted by smart contracts has changed. The operations are now placed in a stack instead of a queue, resulting in a depth-first as opposed to breadth-first execution order.

/!This is a breaking change that affects the security of smart contracts


Normalization RPCs

Two new normalization RPCs, normalize_data and normalize_script, have been added. They can be used to convert Michelson values and scripts that have multiple possible representations into a canonical format. In particular, these RPCs can be used to convert Michelson comb pairs into the format they had before the introduction of the compact notations in Edo.

New failing_noop Operation

A new operation has been added to the protocol that is guaranteed to fail. This feature can be used by tooling (such as tezos-client) to sign arbitrary data securely, without fear of malicious injection into future protocols.


Endorsements Now Checked in Linear Time

Endorsement and double endorsing evidence operations now contain an additional slot field; the slot should be the smallest among the endorser’s slots.

Software that make use of operations and receipts will have to be adapted, in particular indexers.

Most notably, the first list of operations is now composed of endorsement_with_slot instead of endorsement operations.

The change will not affect custom signing stacks, as the endorsement_with_slot is just an unsigned wrapper around the Edo-compatible endorsement format.

The reference endorser forges an endorsement, sends it to the signer, and then wraps the result in an endorsement_with_slot before injection.

/!Breaking change: the format of endorsements and double endorsing evidences has changed

Staking balance RPC

Some users observed degraded performance in v8.1 as reported in issue tezos#1067. To address this, the measurement of staking balance has been reworked, improving the performance of the /chains/[...]/blocks/[...]/context/delegates/[...] RPC endpoint.

Gas Optimizations

Various optimizations have been added to the gas accounting subsystem. Most notably, gas consumption is now computed using saturated arithmetic.


Deactivation of the Test Chain in the Economic Protocol

Prior to Florence, Tezos nodes spawned a test chain during the “Testing” phase of voting for the purpose of allowing users to test the new amendment. However, this feature was both unused in practice and quite complex. It has been removed, simplifying the amendment protocol.

Furthermore, the voting periods have been renamed as follows:
  1. Proposal –> Proposal

  2. Testing_vote –> Exploration

  3. Testing –> Cooldown

  4. Promotion_vote –> Promotion

  5. Adoption –> Adoption


Migrations may now Produce Balance Receipts

Protocol migrations can now update the balance of accounts by producing balance receipts. This was necessary groundwork for Baking Accounts and facilitates developer invoicing.



Abstract protocol types can now be used consistently outside the protocol.