feat(alonzo): add mechanism to compute hashes of common structs

pallas-alonzo/Cargo.toml

@@ -12,8 +12,13 @@ authors = [
     "Santiago Carmuega <santiago@carmuega.me>"
 ]
 
+[features]
+crypto = ["cryptoxide"]
+
 [dependencies]
 minicbor = { version = "0.11.5", features = ["std"] }
 minicbor-derive = "0.7.2"
 hex = "0.4.3"
 log = "0.4.14"
+cryptoxide = { version = "0.3.2", optional = true }
+

pallas-alonzo/src/crypto.rs

@@ -0,0 +1,63 @@
+use crate::{AuxiliaryData, PlutusData, TransactionBody};
+use cryptoxide::blake2b::Blake2b;
+use minicbor::{to_vec, Encode};
+
+pub type Hash32 = [u8; 32];
+
+pub type Error = Box<dyn std::error::Error>;
+
+// TODO: think if we should turn this into a blanket implementation of a new
+// trait
+fn hash_cbor_encodable(data: &impl Encode) -> Result<Hash32, Error> {
+    let bytes = to_vec(data)?;
+    let mut hash = [0; 32];
+    Blake2b::blake2b(&mut hash, &bytes[..], &[]);
+    Ok(hash)
+}
+
+pub fn hash_auxiliary_data(data: &AuxiliaryData) -> Result<Hash32, Error> {
+    hash_cbor_encodable(data)
+}
+
+pub fn hash_transaction(data: &TransactionBody) -> Result<Hash32, Error> {
+    hash_cbor_encodable(data)
+}
+
+pub fn hash_plutus_data(data: &PlutusData) -> Result<Hash32, Error> {
+    hash_cbor_encodable(data)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::BlockWrapper;
+
+    use super::hash_transaction;
+
+    #[test]
+    fn transaction_hash_works() {
+        // TODO: expand this test to include more test blocks
+        let block_idx = 1;
+        let block_str = include_str!("test_data/test1.block");
+
+        let block_bytes = hex::decode(block_str).expect(&format!("bad block file {}", block_idx));
+        let block_model: BlockWrapper = minicbor::decode(&block_bytes[..])
+            .expect(&format!("error decoding cbor for file {}", block_idx));
+
+        let valid_hashes = vec![
+            "8ae0cd531635579a9b52b954a840782d12235251fb1451e5c699e864c677514a",
+            "bb5bb4e1c09c02aa199c60e9f330102912e3ef977bb73ecfd8f790945c6091d4",
+            "8cdd88042ddb6c800714fb1469fb1a1a93152aae3c87a81f2a3016f2ee5c664a",
+            "10add6bdaa7ade06466bdd768456e756709090846b58bf473f240c484db517fa",
+            "8838f5ab27894a6543255aeaec086f7b3405a6db6e7457a541409cdbbf0cd474",
+        ];
+
+        for (tx_idx, tx) in block_model.1.transaction_bodies.iter().enumerate() {
+            let computed_hash = hash_transaction(tx).expect(&format!(
+                "error hashing tx {} from block {}",
+                tx_idx, block_idx
+            ));
+            let known_hash = valid_hashes[tx_idx];
+            assert_eq!(hex::encode(computed_hash), known_hash)
+        }
+    }
+}