[entropy] Change provider interface to simplify supporting many chains

fortuna/Cargo.toml

@@ -1,13 +1,14 @@
 [package]
 name    = "fortuna"
-version = "1.0.0"
+version = "1.1.0"
 edition = "2021"
 
 [dependencies]
 anyhow      = "1.0.75"
 axum        = { version = "0.6.20", features = ["json", "ws", "macros"] }
 axum-macros        = { version = "0.3.8" }
 base64             = { version = "0.21.0" }
+bincode = "1.3.3"
 byteorder   = "1.5.0"
 clap        = { version = "4.4.6", features = ["derive", "cargo", "env"] }
 ethabi      = "18.0.0"

fortuna/src/abi.json

@@ -1,45 +1,4 @@
 [
-  {
-    "inputs": [
-      {
-        "internalType": "uint256",
-        "name": "pythFeeInWei",
-        "type": "uint256"
-      }
-    ],
-    "stateMutability": "nonpayable",
-    "type": "constructor"
-  },
-  {
-    "inputs": [],
-    "name": "AssertionFailure",
-    "type": "error"
-  },
-  {
-    "inputs": [],
-    "name": "IncorrectProviderRevelation",
-    "type": "error"
-  },
-  {
-    "inputs": [],
-    "name": "IncorrectUserRevelation",
-    "type": "error"
-  },
-  {
-    "inputs": [],
-    "name": "InsufficientFee",
-    "type": "error"
-  },
-  {
-    "inputs": [],
-    "name": "NoSuchProvider",
-    "type": "error"
-  },
-  {
-    "inputs": [],
-    "name": "OutOfRandomness",
-    "type": "error"
-  },
   {
     "anonymous": false,
     "inputs": [
@@ -66,9 +25,9 @@
             "type": "uint64"
           },
           {
-            "internalType": "bytes32",
+            "internalType": "bytes",
             "name": "commitmentMetadata",
-            "type": "bytes32"
+            "type": "bytes"
           },
           {
             "internalType": "uint64",
@@ -92,7 +51,7 @@
           }
         ],
         "indexed": false,
-        "internalType": "struct PythRandomStructs.ProviderInfo",
+        "internalType": "struct EntropyStructs.ProviderInfo",
         "name": "provider",
         "type": "tuple"
       }
@@ -130,19 +89,14 @@
             "name": "providerCommitmentSequenceNumber",
             "type": "uint64"
           },
-          {
-            "internalType": "bytes32",
-            "name": "providerCommitmentMetadata",
-            "type": "bytes32"
-          },
           {
             "internalType": "uint256",
             "name": "blockNumber",
             "type": "uint256"
           }
         ],
         "indexed": false,
-        "internalType": "struct PythRandomStructs.Request",
+        "internalType": "struct EntropyStructs.Request",
         "name": "request",
         "type": "tuple"
       }
@@ -180,19 +134,14 @@
             "name": "providerCommitmentSequenceNumber",
             "type": "uint64"
           },
-          {
-            "internalType": "bytes32",
-            "name": "providerCommitmentMetadata",
-            "type": "bytes32"
-          },
           {
             "internalType": "uint256",
             "name": "blockNumber",
             "type": "uint256"
           }
         ],
         "indexed": false,
-        "internalType": "struct PythRandomStructs.Request",
+        "internalType": "struct EntropyStructs.Request",
         "name": "request",
         "type": "tuple"
       },
@@ -337,9 +286,9 @@
             "type": "uint64"
           },
           {
-            "internalType": "bytes32",
+            "internalType": "bytes",
             "name": "commitmentMetadata",
-            "type": "bytes32"
+            "type": "bytes"
           },
           {
             "internalType": "uint64",
@@ -362,7 +311,7 @@
             "type": "uint64"
           }
         ],
-        "internalType": "struct PythRandomStructs.ProviderInfo",
+        "internalType": "struct EntropyStructs.ProviderInfo",
         "name": "info",
         "type": "tuple"
       }
@@ -412,18 +361,13 @@
             "name": "providerCommitmentSequenceNumber",
             "type": "uint64"
           },
-          {
-            "internalType": "bytes32",
-            "name": "providerCommitmentMetadata",
-            "type": "bytes32"
-          },
           {
             "internalType": "uint256",
             "name": "blockNumber",
             "type": "uint256"
           }
         ],
-        "internalType": "struct PythRandomStructs.Request",
+        "internalType": "struct EntropyStructs.Request",
         "name": "req",
         "type": "tuple"
       }
@@ -444,9 +388,9 @@
         "type": "bytes32"
       },
       {
-        "internalType": "bytes32",
+        "internalType": "bytes",
         "name": "commitmentMetadata",
-        "type": "bytes32"
+        "type": "bytes"
       },
       {
         "internalType": "uint64",

fortuna/src/command/register_provider.rs

@@ -11,6 +11,12 @@ use {
     std::sync::Arc,
 };
 
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub struct CommitmentMetadata {
+    pub seed:         [u8; 32],
+    pub chain_length: u64,
+}
+
 /// Register as a randomness provider. This method will generate and commit to a new random
 /// hash chain from the configured secret & a newly generated random value.
 pub async fn register_provider(opts: &RegisterProviderOptions) -> Result<()> {
@@ -25,21 +31,29 @@ pub async fn register_provider(opts: &RegisterProviderOptions) -> Result<()> {
 
     // Create a new random hash chain.
     let random = rand::random::<[u8; 32]>();
-    let mut chain = PebbleHashChain::from_config(&opts.randomness, &opts.chain_id, random)?;
+    let commitment_length = opts.randomness.chain_length;
+    let mut chain = PebbleHashChain::from_config(
+        &opts.randomness.secret,
+        &opts.chain_id,
+        &random,
+        commitment_length,
+    )?;
 
     // Arguments to the contract to register our new provider.
     let fee_in_wei = opts.fee;
     let commitment = chain.reveal()?;
-    // Store the random seed in the metadata field so that we can regenerate the hash chain
-    // at-will. (This is secure because you can't generate the chain unless you also have the secret)
-    let commitment_metadata = random;
-    let commitment_length = opts.randomness.chain_length;
+    // Store the random seed and chain length in the metadata field so that we can regenerate the hash
+    // chain at-will. (This is secure because you can't generate the chain unless you also have the secret)
+    let commitment_metadata = CommitmentMetadata {
+        seed:         random,
+        chain_length: commitment_length,
+    };
 
     if let Some(r) = contract
         .register(
             fee_in_wei,
             commitment,
-            commitment_metadata,
+            bincode::serialize(&commitment_metadata)?.into(),
             commitment_length,
         )
         .send()

fortuna/src/command/run.rs

@@ -2,6 +2,7 @@ use {
     crate::{
         api,
         chain::ethereum::PythContract,
+        command::register_provider::CommitmentMetadata,
         config::{
             Config,
             RunOptions,
@@ -59,8 +60,15 @@ pub async fn run(opts: &RunOptions) -> Result<()> {
         // TODO: we may want to load the hash chain in a lazy/fault-tolerant way. If there are many blockchains,
         // then it's more likely that some RPC fails. We should tolerate these faults and generate the hash chain
         // later when a user request comes in for that chain.
-        let random: [u8; 32] = provider_info.commitment_metadata;
-        let hash_chain = PebbleHashChain::from_config(&opts.randomness, &chain_id, random)?;
+        let metadata =
+            bincode::deserialize::<CommitmentMetadata>(&provider_info.commitment_metadata)?;
+
+        let hash_chain = PebbleHashChain::from_config(
+            &opts.randomness.secret,
+            &chain_id,
+            &metadata.seed,
+            metadata.chain_length,
+        )?;
         let chain_state = HashChainState {
             offsets:     vec![provider_info
                 .original_commitment_sequence_number

fortuna/src/state.rs

@@ -1,8 +1,5 @@
 use {
-    crate::{
-        api::ChainId,
-        config::RandomnessOptions,
-    },
+    crate::api::ChainId,
     anyhow::{
         ensure,
         Result,
@@ -36,17 +33,18 @@ impl PebbleHashChain {
     }
 
     pub fn from_config(
-        opts: &RandomnessOptions,
+        secret: &str,
         chain_id: &ChainId,
-        random: [u8; 32],
+        random: &[u8; 32],
+        chain_length: u64,
     ) -> Result<Self> {
         let mut input: Vec<u8> = vec![];
-        input.extend_from_slice(&hex::decode(opts.secret.clone())?);
+        input.extend_from_slice(&hex::decode(secret)?);
         input.extend_from_slice(&chain_id.as_bytes());
-        input.extend_from_slice(&random);
+        input.extend_from_slice(random);
 
         let secret: [u8; 32] = Keccak256::digest(input).into();
-        Ok(Self::new(secret, opts.chain_length.try_into()?))
+        Ok(Self::new(secret, chain_length.try_into()?))
     }
 
     /// Reveal the next hash in the chain using the previous proof.

target_chains/ethereum/contracts/contracts/entropy/Entropy.sol

@@ -95,7 +95,7 @@ contract Entropy is IEntropy, EntropyState {
     function register(
         uint feeInWei,
         bytes32 commitment,
-        bytes32 commitmentMetadata,
+        bytes calldata commitmentMetadata,
         uint64 chainLength
     ) public override {
         if (chainLength == 0) revert EntropyErrors.AssertionFailure();
@@ -186,7 +186,6 @@ contract Entropy is IEntropy, EntropyState {
         req.providerCommitment = providerInfo.currentCommitment;
         req.providerCommitmentSequenceNumber = providerInfo
             .currentCommitmentSequenceNumber;
-        req.providerCommitmentMetadata = providerInfo.commitmentMetadata;
 
         if (useBlockHash) {
             req.blockNumber = block.number;

target_chains/ethereum/contracts/forge-test/Entropy.t.sol

@@ -44,19 +44,14 @@ contract EntropyTest is Test {
         random.register(
             provider1FeeInWei,
             provider1Proofs[0],
-            bytes32(keccak256(abi.encodePacked(uint256(0x0100)))),
+            hex"0100",
             provider1ChainLength
         );
 
         bytes32[] memory hashChain2 = generateHashChain(provider2, 0, 100);
         provider2Proofs = hashChain2;
         vm.prank(provider2);
-        random.register(
-            provider2FeeInWei,
-            provider2Proofs[0],
-            bytes32(keccak256(abi.encodePacked(uint256(0x0200)))),
-            100
-        );
+        random.register(provider2FeeInWei, provider2Proofs[0], hex"0200", 100);
     }
 
     function generateHashChain(
@@ -323,12 +318,7 @@ contract EntropyTest is Test {
             10
         );
         vm.prank(provider1);
-        random.register(
-            provider1FeeInWei,
-            newHashChain[0],
-            bytes32(keccak256(abi.encodePacked(uint256(0x0100)))),
-            10
-        );
+        random.register(provider1FeeInWei, newHashChain[0], hex"0100", 10);
         assertInvariants();
         EntropyStructs.ProviderInfo memory info1 = random.getProviderInfo(
             provider1
@@ -397,12 +387,7 @@ contract EntropyTest is Test {
 
         // Check that overflowing the fee arithmetic causes the transaction to revert.
         vm.prank(provider1);
-        random.register(
-            MAX_UINT256,
-            provider1Proofs[0],
-            bytes32(keccak256(abi.encodePacked(uint256(0x0100)))),
-            100
-        );
+        random.register(MAX_UINT256, provider1Proofs[0], hex"0100", 100);
         vm.expectRevert();
         random.getFee(provider1);
     }
@@ -452,12 +437,7 @@ contract EntropyTest is Test {
 
         // Reregistering updates the required fees
         vm.prank(provider1);
-        random.register(
-            12345,
-            provider1Proofs[0],
-            bytes32(keccak256(abi.encodePacked(uint256(0x0100)))),
-            100
-        );
+        random.register(12345, provider1Proofs[0], hex"0100", 100);
 
         assertRequestReverts(pythFeeInWei + 12345 - 1, provider1, 42, false);
         requestWithFee(user2, pythFeeInWei + 12345, provider1, 42, false);