1 files changed, 77 insertions, 0 deletions
diff --git a/src/psbt.h b/src/psbt.h
index 9390b38eee..36a3d2ca16 100644
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -10,8 +10,11 @@
 #include <policy/feerate.h>
 #include <primitives/transaction.h>
 #include <pubkey.h>
+#include <script/keyorigin.h>
 #include <script/sign.h>
 #include <script/signingprovider.h>
+#include <span.h>
+#include <streams.h>
 
 #include <optional>
 
@@ -68,6 +71,80 @@ struct PSBTProprietary
     }
 };
 
+// Takes a stream and multiple arguments and serializes them as if first serialized into a vector and then into the stream
+// The resulting output into the stream has the total serialized length of all of the objects followed by all objects concatenated with each other.
+template<typename Stream, typename... X>
+void SerializeToVector(Stream& s, const X&... args)
+{
+    WriteCompactSize(s, GetSerializeSizeMany(s.GetVersion(), args...));
+    SerializeMany(s, args...);
+}
+
+// Takes a stream and multiple arguments and unserializes them first as a vector then each object individually in the order provided in the arguments
+template<typename Stream, typename... X>
+void UnserializeFromVector(Stream& s, X&... args)
+{
+    size_t expected_size = ReadCompactSize(s);
+    size_t remaining_before = s.size();
+    UnserializeMany(s, args...);
+    size_t remaining_after = s.size();
+    if (remaining_after + expected_size != remaining_before) {
+        throw std::ios_base::failure("Size of value was not the stated size");
+    }
+}
+
+// Deserialize HD keypaths into a map
+template<typename Stream>
+void DeserializeHDKeypaths(Stream& s, const std::vector<unsigned char>& key, std::map<CPubKey, KeyOriginInfo>& hd_keypaths)
+{
+    // Make sure that the key is the size of pubkey + 1
+    if (key.size() != CPubKey::SIZE + 1 && key.size() != CPubKey::COMPRESSED_SIZE + 1) {
+        throw std::ios_base::failure("Size of key was not the expected size for the type BIP32 keypath");
+    }
+    // Read in the pubkey from key
+    CPubKey pubkey(key.begin() + 1, key.end());
+    if (!pubkey.IsFullyValid()) {
+       throw std::ios_base::failure("Invalid pubkey");
+    }
+    if (hd_keypaths.count(pubkey) > 0) {
+        throw std::ios_base::failure("Duplicate Key, pubkey derivation path already provided");
+    }
+
+    // Read in key path
+    uint64_t value_len = ReadCompactSize(s);
+    if (value_len % 4 || value_len == 0) {
+        throw std::ios_base::failure("Invalid length for HD key path");
+    }
+
+    KeyOriginInfo keypath;
+    s >> keypath.fingerprint;
+    for (unsigned int i = 4; i < value_len; i += sizeof(uint32_t)) {
+        uint32_t index;
+        s >> index;
+        keypath.path.push_back(index);
+    }
+
+    // Add to map
+    hd_keypaths.emplace(pubkey, std::move(keypath));
+}
+
+// Serialize HD keypaths to a stream from a map
+template<typename Stream>
+void SerializeHDKeypaths(Stream& s, const std::map<CPubKey, KeyOriginInfo>& hd_keypaths, CompactSizeWriter type)
+{
+    for (auto keypath_pair : hd_keypaths) {
+        if (!keypath_pair.first.IsValid()) {
+            throw std::ios_base::failure("Invalid CPubKey being serialized");
+        }
+        SerializeToVector(s, type, Span{keypath_pair.first});
+        WriteCompactSize(s, (keypath_pair.second.path.size() + 1) * sizeof(uint32_t));
+        s << keypath_pair.second.fingerprint;
+        for (const auto& path : keypath_pair.second.path) {
+            s << path;
+        }
+    }
+}
+
 /** A structure for PSBTs which contain per-input information */
 struct PSBTInput
 {