init: cryptographic append-only ledger

crates/ledger-core/tests/read_proof.rs

@@ -0,0 +1,29 @@
+use ledger_core::{ReadProofV0, verify_read_proof_v0};
+
+fn leaf(i: u64) -> [u8; 32] {
+    blake3::hash(format!("leaf-{}", i).as_bytes()).into()
+}
+
+#[test]
+fn read_proof_verifies_for_all_leaves() {
+    for n in 1..=33usize {
+        let leaves: Vec<[u8; 32]> = (0..n as u64).map(leaf).collect();
+        for idx in 0..n {
+            let proof = ReadProofV0::from_tree(&leaves, idx).expect("build proof");
+            verify_read_proof_v0(&proof).expect("verify proof");
+        }
+    }
+}
+
+#[test]
+fn read_proof_rejects_tampering() {
+    let leaves: Vec<[u8; 32]> = (0..8u64).map(leaf).collect();
+    let mut proof = ReadProofV0::from_tree(&leaves, 3).expect("build proof");
+    assert!(verify_read_proof_v0(&proof).is_ok());
+
+    // Flip one nibble in the first sibling hash.
+    let mut s = proof.path[0].sibling_hash_hex.clone();
+    s.replace_range(0..1, if &s[0..1] == "0" { "1" } else { "0" });
+    proof.path[0].sibling_hash_hex = s;
+    assert!(verify_read_proof_v0(&proof).is_err());
+}