**Prover selection method analysis:**

Question to think about: How does a prover selection model/prover environment affect:
* decentralization?
* liveness?
* permissionless entry?
* efficiency and competition?
* availability of a valid proof
* prover rewards/profitability?
* resilience to attacks?

**1. Random selection through VRF** or **Rotating queue:** (provers are not vetted)
* decentralization: yes
* liveness: yes, if there is at least one honest active prover that generates proofs
* permissionless entry: yes
* efficiency and competition: no waste of compute resource but no incentive for efficiency either
* availability of a valid proof: risk of invalid proof exists due do randomness and not-vetted provers
* prover rewards/profitability: equal distribution of rewards
* resilience to attacks: risk of potential collusion/Sybil attacks => mitigation mechanism to be implemented

**2. Competitive approaches:** (provers are vetted by the computing power required to win)

**Proof racing** or **Proof Mining:**
* decentralization: higher chance for centralization
* liveness: centralization can increase risks of liveness failure
* permissionless entry: theoretically yes, but compute requirements can increase entry barrier
* efficiency and competition: high competition and low efficiency due to the waste of compute resource which can increase gas fees as well
* availability of a valid proof: yes, probability of a valid proof is very high as long as multiple provers are competing
* prover rewards/profitability: potential concentration/centralization of rewards
* resilience to attacks: more prone to attacks due to prover centralization

NOTE: the entry barrier can be lower in case of proof mining if the challenges to be solved by the provers are easier than the proof generation itself, this may affect network health, decentralization and other factors as well.

**3. Staking-based approaches:** stake amount should be upper-bound to remain inclusive
1. **Staking-based proving with random selection or rotating queue**: provers are vetted based on the stake provided
* decentralization: risk of centralization if the stake amount is high,
* liveness: yes, if there is at least one honest active prover that can generate proofs
* permissionless entry: depends on the amount of stake required, only provers that can provide the stake can participate
* efficiency and competition: no waste of compute resource but no incentive for efficiency or healthy competition either
* availability of a valid proof: yes, risk of an invalid proof is very low due to the potential slashing in case of failure
* prover rewards/profitability: equal distribution of rewards
* resilience to attacks: chances for certain attacks (51%, etc) are lower due to the financial requirements but there is still risk of potential collusion/Sybil attacks => mitigation mechanism to be implemented

2. **Staking-based proving combined with reputation ratio (& random selection)**: provers are vetted based on the stake provided and their past performance
* decentralization: risk of centralization in case of high stake requirement,
* liveness: yes, if there is at least one honest active prover that can generate proofs
* permissionless entry: depends on the amount of stake required, only provers that can provide the stake can participate
* efficiency and competition: competition driven by and aiming for reliability/reputation, no waste of compute resources
* availability of a valid proof: yes, risk of an invalid proof is minimal (due to the potential slashing, and the selection among reputable provers)
* prover rewards/profitability: provers with higher reliability receive more rewards
* resilience to attacks: chances for attacks are pretty low due to the model incentivising honest and reliable behavior

**4. Auction-based approaches:** (lowest bid to generate the proof)
1. **Pure auction with prover bids**
* decentralization: yes, but there is some chance of centralization due to most resourceful provers if they kill
* liveness: yes, if there is at least one honest active prover that submits a bid
* permissionless entry: yes
* efficiency and competition: increased efficiency and competition for cheap proofs, no waste of compute resources
* availability of a valid proof: yes, risk of an invalid proof is minimal as long as there is more than one prover bidding
* prover rewards/profitability: more efficient provers receive more rewards
* resilience to attacks: risk of potential collusion/Sybil attacks, but there can be also malicious bidders submitting invalid proofs on purpose, or economically powerful provers submitting bids with losses to kill competition and gain dominance
2. **Staking-based proving with prover bids**
* decentralization: yes, but there is some risk of centralization if the stake amount is high,
* liveness: yes, if there is at least one honest active prover that submits a bid
* permissionless entry: depends on the amount of stake required, only provers that can provide the stake can participate
* efficiency and competition: increased efficiency and competition for cheap proofs, no waste of compute resources
* availability of a valid proof: yes, risk of an invalid proof is very minimal due to stake requirement
* prover rewards/profitability: more efficient provers receive more rewards
* resilience to attacks: chances for attacks are pretty low due to the model incentivising honest and reliable behavior, but there can be economically powerful provers submitting bids with losses to kill competition and gain dominance

**5. Alternative ideas for combined models:**
1. **Random selection of 5 provers and then proof racing** among them
* decentralization: yes
* liveness: yes
* permissionless entry: yes
* efficiency and competition: some inefficiency due to the waste of compute resources among the selected provers but this is limited by selecting only x number of competing provers
* availability of a valid proof: yes, probability of a valid proof is very high due to multiple provers generating a proof, the above mentioned inefficiency in the form of wasting some compute resources actually increases the chances of a valid proof
* prover rewards/profitability: fairly equal distribution of rewards due to random selection
* resilience to attacks: risk of potential collusion/Sybil attacks => mitigation mechanism to be implemented
2. **Random selection of 3 provers from a pool of the 32/64/128 most reputable provers and then proof racing** among them:
* decentralization: yes
* liveness: yes
* permissionless entry: yes
* efficiency and competition: competition driven by and aiming for reliability/reputation, even less waste of compute resources than above
* availability of a valid proof: yes, probability of a valid proof is very high due to multiple reputable provers generating a proof,
* prover rewards/profitability: fairly equal distribution of rewards due to random selection, provers with higher reliability have higher chances to get rewarded
* resilience to attacks: chances for attacks are pretty low due to the model incentivising honest and reliable behavior, but there is risk of potential collusion/Sybil attacks => mitigation mechanism to be implemented