Adds a `disable_pow` field and skips checking proof of work if it's true

zebra-chain/src/parameters/network.rs

@@ -189,6 +189,15 @@ impl Network {
         }
     }
 
+    /// Returns true if proof-of-work validation should be disabled for this network
+    pub fn disable_pow(&self) -> bool {
+        if let Self::Testnet(params) = self {
+            params.disable_pow()
+        } else {
+            false
+        }
+    }
+
     /// Returns the [`NetworkKind`] for this network.
     pub fn kind(&self) -> NetworkKind {
         match self {

zebra-chain/src/parameters/network/testnet.rs

@@ -71,6 +71,8 @@ pub struct ParametersBuilder {
     hrp_sapling_extended_full_viewing_key: String,
     /// Sapling payment address human-readable prefix for this network
     hrp_sapling_payment_address: String,
+    /// A flag for disabling proof-of-work checks when Zebra is validating blocks
+    disable_pow: bool,
 }
 
 impl Default for ParametersBuilder {
@@ -91,6 +93,7 @@ impl Default for ParametersBuilder {
             genesis_hash: TESTNET_GENESIS_HASH
                 .parse()
                 .expect("hard-coded hash parses"),
+            disable_pow: false,
         }
     }
 }
@@ -231,6 +234,12 @@ impl ParametersBuilder {
         self
     }
 
+    /// Sets the `disable_pow` flag to be used in the [`Parameters`] being built.
+    pub fn with_disable_pow(mut self, disable_pow: bool) -> Self {
+        self.disable_pow = disable_pow;
+        self
+    }
+
     /// Converts the builder to a [`Parameters`] struct
     pub fn finish(self) -> Parameters {
         let Self {
@@ -240,14 +249,16 @@ impl ParametersBuilder {
             hrp_sapling_extended_spending_key,
             hrp_sapling_extended_full_viewing_key,
             hrp_sapling_payment_address,
+            disable_pow,
         } = self;
         Parameters {
             network_name,
+            genesis_hash,
             activation_heights,
             hrp_sapling_extended_spending_key,
             hrp_sapling_extended_full_viewing_key,
             hrp_sapling_payment_address,
-            genesis_hash,
+            disable_pow,
         }
     }
 
@@ -276,6 +287,8 @@ pub struct Parameters {
     hrp_sapling_extended_full_viewing_key: String,
     /// Sapling payment address human-readable prefix for this network
     hrp_sapling_payment_address: String,
+    /// A flag for disabling proof-of-work checks when Zebra is validating blocks
+    disable_pow: bool,
 }
 
 impl Default for Parameters {
@@ -302,6 +315,7 @@ impl Parameters {
             network_name: "Regtest".to_string(),
             ..Self::build()
                 .with_genesis_hash(REGTEST_GENESIS_HASH)
+                .with_disable_pow(true)
                 .with_sapling_hrps(
                     zp_constants::regtest::HRP_SAPLING_EXTENDED_SPENDING_KEY,
                     zp_constants::regtest::HRP_SAPLING_EXTENDED_FULL_VIEWING_KEY,
@@ -329,6 +343,7 @@ impl Parameters {
             hrp_sapling_extended_spending_key,
             hrp_sapling_extended_full_viewing_key,
             hrp_sapling_payment_address,
+            disable_pow,
         } = Self::new_regtest(ConfiguredActivationHeights::default());
 
         self.network_name == network_name
@@ -336,6 +351,7 @@ impl Parameters {
             && self.hrp_sapling_extended_spending_key == hrp_sapling_extended_spending_key
             && self.hrp_sapling_extended_full_viewing_key == hrp_sapling_extended_full_viewing_key
             && self.hrp_sapling_payment_address == hrp_sapling_payment_address
+            && self.disable_pow == disable_pow
     }
 
     /// Returns the network name
@@ -367,4 +383,9 @@ impl Parameters {
     pub fn hrp_sapling_payment_address(&self) -> &str {
         &self.hrp_sapling_payment_address
     }
+
+    /// Returns true if proof-of-work validation should be disabled for this network
+    pub fn disable_pow(&self) -> bool {
+        self.disable_pow
+    }
 }

zebra-consensus/src/block.rs

@@ -176,16 +176,18 @@ where
                 Err(BlockError::MaxHeight(height, hash, block::Height::MAX))?;
             }
 
-            // > The block data MUST be validated and checked against the server's usual
+            if !network.disable_pow() {
-            // > acceptance rules (excluding the check for a valid proof-of-work).
+                // > The block data MUST be validated and checked against the server's usual
-            // <https://en.bitcoin.it/wiki/BIP_0023#Block_Proposal>
+                // > acceptance rules (excluding the check for a valid proof-of-work).
-            if request.is_proposal() {
+                // <https://en.bitcoin.it/wiki/BIP_0023#Block_Proposal>
-                check::difficulty_threshold_is_valid(&block.header, &network, &height, &hash)?;
+                if request.is_proposal() {
-            } else {
+                    check::difficulty_threshold_is_valid(&block.header, &network, &height, &hash)?;
-                // Do the difficulty checks first, to raise the threshold for
+                } else {
-                // attacks that use any other fields.
+                    // Do the difficulty checks first, to raise the threshold for
-                check::difficulty_is_valid(&block.header, &network, &height, &hash)?;
+                    // attacks that use any other fields.
-                check::equihash_solution_is_valid(&block.header)?;
+                    check::difficulty_is_valid(&block.header, &network, &height, &hash)?;
+                    check::equihash_solution_is_valid(&block.header)?;
+                }
             }
 
             // Next, check the Merkle root validity, to ensure that

zebra-consensus/src/checkpoint.rs

@@ -595,8 +595,10 @@ where
             .ok_or(VerifyCheckpointError::CoinbaseHeight { hash })?;
         self.check_height(height)?;
 
-        crate::block::check::difficulty_is_valid(&block.header, &self.network, &height, &hash)?;
+        if !self.network.disable_pow() {
-        crate::block::check::equihash_solution_is_valid(&block.header)?;
+            crate::block::check::difficulty_is_valid(&block.header, &self.network, &height, &hash)?;
+            crate::block::check::equihash_solution_is_valid(&block.header)?;
+        }
 
         // don't do precalculation until the block passes basic difficulty checks
         let block = CheckpointVerifiedBlock::with_hash(block, hash);