Ethereum 2.0 uses a proof-of-stake mechanism to protect the network, that is, many computer threads called “verifiers” vote to decide which block can be chained (the so-called “attesting” to witness), of course, they will also propose Alternate block. However, the verifier is not just “on” and “off” two states: from becoming a verifier to exiting the verifier throughout the life cycle, its state will undergo multiple transitions. This article will delve into the life cycle of the verifier, show the essence of each stage and conversion process, how to trigger the conversion, and the duration of each conversion 1 .
First explain the time unit
The time in Ethereum 2.0 is usually measured in units of “epoch (period)”. One period is 384 seconds, which is six and a half minutes. For ease of understanding, the time based on this measure has been converted to minutes, hours, and days, and detailed information is provided in the footnotes of the appendix.
Verifier life cycle overview
Before we dive into the details, let’s take a look at the overview of the validator’s life cycle and understand the terminology used to express different states.
-Figure 1: List of validator life cycles-The stages shown on each tab are as follows:
- We have been deposited Margin (Deposited): Margin offer has been packaged Ethernet 1.0 square block chain
- Awaiting activation (Pending): Margin offer is accepted by the network Ethernet Square 2.0
- Active (Active): verifier to witness blocks and blocks of the proposal
- About to exit (Exiting): verifier will stop and witness proposed block
- Forfeited (Slashing): Because caught cheating, verify the witness to stop and block the proposal
- Completely out (Exited): verifier completely out, no longer involved in any of the processes
It can thus define a basic state: ” being witness (attesting)”, activate, and the initiative to withdraw completely withdraw are in this state, in this state who allegedly looked to witness and verify the proposed blocks. This state is the most important. In this state, the verifier needs to connect to the Ethereum 2.0 network and synchronize data to perform their responsibilities and avoid being punished.
-Figure 2: “Witnessing” state-After defining these stages, let’s examine the transition process between them in detail.
Margin deposit stage
The acceptance of the margin offer is the beginning of the validator’s career; this acceptance process takes place on the Ethereum 1.0 chain because the validator funds are originally placed on the Ethereum 1.0 chain. But when the 1.0 chain is accepted, the 2.0 chain cannot yet perceive this deposit.
The deposit period of the validator’s margin takes approximately 7.5 hours 2 to ensure that the chain reorganization affects the order of Eth1 transactions and the probability of invalidating the margin offer is sufficiently small. After this phase is completed, the verifier enters awaiting activation stage 3 .
-Figure 3: From the deposit phase to the activation phase-
Waiting for activation phase
After the deposit is deposited on the Eth1 chain long enough, it will be accepted by the Eth2 chain. This marks the organization that the verifier officially started accepting Eth2. Assuming that a validator has deposited at least 32 ETH 4 , then the TA can begin to witness.
The validators waiting for activation will form a queue: at a point in time, the number of validators that can be activated and withdrawn on the Eth2 chain is a relatively small number (so have to queue) 5 to ensure the stability of the validator set. If the queue is empty, then wait to activate the certifier will activate in about 25 minutes after 6 ; if the queue is very long, it may be days or even weeks to activate. However, after lining up, the verifier can directly activate and participate in the witness.
-Figure 4: From waiting for activation to active phase-
Active phase
Generally speaking, a verifier spends most of its time at this stage. Active verifiers send out a witness message about every 6 minutes, and occasionally have to propose block 7 themselves . The verifier will remain active unless the following three situations occur:
- The verifier was punished for failing to send a witness message in time, and eventually the balance was lower than 16 ETH
- The verifier voluntarily requested to quit by sending a corresponding transaction (this transaction cannot be issued within 9 days of activation)
- The verifier proved to be evil
In the first two cases, the verifier will be added to the exit queue (the number of validators who can leave the active state within a certain period of time is also limited, just as the number of validators that can enter is limited, about 1 every few minutes A).
-Figure 5: From activated state to leaving soon-In the third case, the verification will be added to the perpetrator queue and be punished.
-Figure 6: From the activated state to the forfeited state-It is worth noting that if necessary, the verifier can always send an additional margin offer (containing the same verifier information) to “recharge” the balance (but the upper limit of the effective balance Yes 32). This will prevent the verifier’s balance from being lower than 16 from being placed in the exit queue.
Exiting soon
Although verifiers who actively withdrew expressed their desire to stop verification (whether voluntary or forced), they cannot immediately withdraw. On the contrary, although they are about to exit, they still have to take on their responsibilities as usual. This ensures the stability of the network and avoids the impact of the verifier’s immediate withdrawal.
Just like a validator has a waiting activation state and a queue when it wants to activate, a validator who wants to withdraw also has a queue, and only a small number of validators are allowed to withdraw for a period of time. Likewise, the time it takes to take the initiative to exit depends on how many validators are in the top.
-Figure 7: From exiting to exiting completely-
Confiscated
If the verifier is caught after violating the agreement, he will be immediately forfeited 1 ETH (deducted from his balance), and then enter the forfeited state, which is similar to the exiting state, but also subject to punishment. We discuss this point in the “Full Exit” section below.
-Figure 8: From being confiscated to completely withdrawing-a validator who is about to leave or has completely withdrawn may be confiscated (the validator has a period of time before completely withdrawing funds to withdraw funds, during which time he can be fined ). This prevents the evil verifier from using the normal exit mechanism to escape before the evil is discovered. The result is that the state model becomes more complex:
-Figure 9: After adding the penalty conditions-
Quit completely
When transitioning to the full exit state, the verifier officially ended his work, no longer need to witness and propose blocks, and no longer need to closely follow the real-time dynamics of the Eth2 blockchain.
After the transition to the exit status, there is a delay of about 8 days before the balance of the verifier can be withdrawn. However, if a validator completely withdraws from the confiscated state, then two additional penalties will be accepted.
The first, completely withdraw from the president to be able to withdraw much interval, to 36 days 9 . Secondly, during these 36 days, the system will also impose further penalties on the verifier based on the number of verifiers that were confiscated within 18 days before and after the point of time when the verifier was caught by evildoers. Then the validator’s effective balance loss ratio 10 will be as shown in the figure below:
-Figure 10: Relationship between the valid balance confiscated and the percentage of validators confiscated during the same period-After the 36-day cycle is over, the remaining balance of confiscated validators can be taken away.
As can be seen from this life flow diagram, there is no additional mechanism for a retired verifier to reactivate. Therefore, once a verifier withdraws, its funds will remain dormant, waiting for the verifier to come and take it away. However, when Eth2 Phase 0, funds cannot be transferred-so all funds of the certifiers who have completely withdrawn are still stored in the pledge system until the transfer function is turned on. There is no transfer function because the user account mode has not been introduced.
Supplemented validator life process
Add all the above details to the flow chart, you can get a complete picture:
-Figure 11: Supplemented Verifier Life Flow Chart-Please take a closer look at the supplementary conditions, the duration of each stage, and the conversion process. These details are critical to the successful operation of the Eth2 verification facility. From initializing the margin to removing the margin, this life flow chart points out what may happen at each stage, and also provides a clear explanation for the verifier’s performance throughout the period.
Note 1: It should be noted that the Ethereum 2.0 specification does not have an explicit state machine, so the names of each stage are given by the author for ease of description.
Note 2: The time of 1024 Ethereum 1.0 blocks plus 32 Ethereum 2.0 time slots.
Note 3: It is assumed here that the verifier has enough 32 ETH. If there is not enough deposit, the verifier will stay in the deposit period until the verifier initiates a margin offer to make the balance exceed 32 ETH.
Note 4: If it is less than 32 ETH, it can be re-deposited to increase the balance of the verifier.
Note 5: There are (number of active validators + number of active exit validators + number of validated validators) / 63356 places in each period, and the lower limit is 4.
Note 6: That is the length of 4 periods.
Note 7: Every validator needs to send a witness message in a certain slot in a period, and every validator will be randomly selected as a block proposer.
Note 8: 256 periods.
Note 9: 8192 periods.
Note 10: Note that the maximum penalty is 100% of the effective balance, but the upper limit of the effective balance is 32 ETH, regardless of the verifier’s actual balance.