last hash

src/processor/claim.rs

@@ -54,9 +54,6 @@ pub fn process_claim<'a, 'info>(
         .checked_sub(amount)
         .ok_or(OreError::ClaimTooLarge)?;
 
-    // Update timestamp
-    proof.last_claim_at = clock.unix_timestamp;
-
     // Distribute tokens from treasury to beneficiary
     solana_program::program::invoke_signed(
         &spl_token::instruction::transfer(

src/processor/mine.rs

@@ -169,6 +169,7 @@ pub fn process_mine<'a, 'info>(
     proof.balance = proof.balance.saturating_add(reward_actual);
 
     // Hash recent slot hash into the next challenge to prevent pre-mining attacks
+    proof.last_hash = hash.h;
     proof.challenge = hashv(&[
         hash.h.as_slice(),
         &slot_hashes_sysvar.data.borrow()[0..size_of::<SlotHash>()],

src/processor/register.rs

@@ -72,7 +72,7 @@ pub fn process_register<'a, 'info>(
         &slot_hashes_info.data.borrow()[0..size_of::<SlotHash>()],
     ])
     .0;
-    proof.last_claim_at = clock.unix_timestamp;
+    proof.last_hash = [0; 32];
     proof.last_hash_at = clock.unix_timestamp;
     proof.last_stake_at = clock.unix_timestamp;
     proof.total_hashes = 0;

src/state/proof.rs

@@ -21,8 +21,8 @@ pub struct Proof {
     /// The current mining challenge.
     pub challenge: [u8; 32],
 
-    /// The last time this account claimed rewards.
-    pub last_claim_at: i64,
+    /// The last hash the miner provided.
+    pub last_hash: [u8; 32],
 
     /// The last time this account provided a hash.
     pub last_hash_at: i64,