From a1c6d209437341ba0293699a31008ab90a5d8877 Mon Sep 17 00:00:00 2001
From: Zicklag <zicklag@katharostech.com>
Date: Wed, 17 Dec 2025 21:27:18 -0600
Subject: [PATCH] fix: fix did derivation and signature generation.

This fixes two bugs that were affecting did derivation and signature
generation.

- The `UnsignedOperation` and `Operation` types were not serializing
  prev as `null` and were instead skipping serialization when it was
  `None`.
- The DID was being calculated from the hash of the JSON encoding
  instead of the CBOR encoding.
---
 src/builder.rs    | 6 +++---
 src/operations.rs | 8 +++-----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/builder.rs b/src/builder.rs
index b25d7d9..6bf7908 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -3,7 +3,7 @@
 use crate::crypto::SigningKey;
 use crate::did::Did;
 use crate::document::ServiceEndpoint;
-use crate::encoding::{base32_encode, sha256};
+use crate::encoding::{base32_encode, dag_cbor_encode, sha256};
 use crate::error::{PlcError, Result};
 use crate::operations::{Operation, UnsignedOperation};
 use crate::validation::{
@@ -229,8 +229,8 @@ impl DidBuilder {
 
         // The DID is derived from the CID by taking the hash portion
         // For simplicity, we'll hash the entire serialized operation
-        let serialized = serde_json::to_vec(operation)
-            .map_err(|e| PlcError::DagCborError(e.to_string()))?;
+        let serialized =
+            dag_cbor_encode(operation).map_err(|e| PlcError::DagCborError(e.to_string()))?;
 
         let hash = sha256(&serialized);
         let encoded = base32_encode(&hash);
diff --git a/src/operations.rs b/src/operations.rs
index 33e27ae..3ee14d6 100644
--- a/src/operations.rs
+++ b/src/operations.rs
@@ -30,7 +30,6 @@ pub enum Operation {
         services: HashMap<String, ServiceEndpoint>,
 
         /// Previous operation CID (null for genesis)
-        #[serde(skip_serializing_if = "Option::is_none")]
         prev: Option<String>,
 
         /// Base64url-encoded signature
@@ -193,9 +192,9 @@ impl Operation {
                 services: services.clone(),
                 prev: prev.clone(),
             },
-            Operation::PlcTombstone { prev, .. } => UnsignedOperation::PlcTombstone {
-                prev: prev.clone(),
-            },
+            Operation::PlcTombstone { prev, .. } => {
+                UnsignedOperation::PlcTombstone { prev: prev.clone() }
+            }
             Operation::LegacyCreate {
                 signing_key,
                 recovery_key,
@@ -247,7 +246,6 @@ pub enum UnsignedOperation {
         services: HashMap<String, ServiceEndpoint>,
 
         /// CID of previous operation (None for genesis)
-        #[serde(skip_serializing_if = "Option::is_none")]
         prev: Option<String>,
     },
 
-- 
2.43.0