feat(crypto): BIP-32/39/84, HD accounts, SLIP-132

2026-06-11 10:46:36 +02:00
parent cdd19024ad
commit 8a0dc920f6
4 changed files with 407 additions and 0 deletions
@@ -0,0 +1,96 @@
+using NBitcoin;
+using NBitcoin.DataEncoders;
+using PalladiumWallet.Core.Chain;
+
+namespace PalladiumWallet.Core.Crypto;
+
+/// <summary>
+/// Serializzazione e parsing SLIP-132 delle chiavi estese (xprv/yprv/zprv e
+/// varianti pubbliche) con gli header di <see cref="ChainProfile.ExtKeyHeaders"/>
+/// (blueprint §3). NBitcoin serializza con i soli header registrati nella Network
+/// (xprv/xpub): le altre varianti si compongono qui come
+/// Base58Check( header 4 byte BE || payload BIP32 74 byte ).
+/// </summary>
+public static class Slip132
+{
+    public static string Encode(ExtPubKey key, ScriptKind kind, ChainProfile profile) =>
+        Encoders.Base58Check.EncodeData([.. profile.ExtKeyHeaders[kind].PublicBytes(), .. key.ToBytes()]);
+
+    public static string Encode(ExtKey key, ScriptKind kind, ChainProfile profile) =>
+        Encoders.Base58Check.EncodeData([.. profile.ExtKeyHeaders[kind].PrivateBytes(), .. key.ToBytes()]);
+
+    /// <summary>
+    /// Riconosce l'header (→ ScriptKind) e decodifica una chiave pubblica estesa:
+    /// è la via dell'import watch-only (§4.4).
+    /// </summary>
+    public static bool TryDecodePublic(string encoded, ChainProfile profile,
+        out ExtPubKey? key, out ScriptKind kind)
+    {
+        key = null;
+        kind = default;
+        if (!TryDecodePayload(encoded, profile, isPrivate: false, out var payload, out kind))
+            return false;
+        try
+        {
+            key = new ExtPubKey(payload!);
+            return true;
+        }
+        catch (FormatException)
+        {
+            return false;
+        }
+    }
+
+    /// <summary>Come <see cref="TryDecodePublic"/>, per chiavi private (import spendibile).</summary>
+    public static bool TryDecodePrivate(string encoded, ChainProfile profile,
+        out ExtKey? key, out ScriptKind kind)
+    {
+        key = null;
+        kind = default;
+        if (!TryDecodePayload(encoded, profile, isPrivate: true, out var payload, out kind))
+            return false;
+        try
+        {
+            key = ExtKey.CreateFromBytes(payload!);
+            return true;
+        }
+        catch (FormatException)
+        {
+            return false;
+        }
+    }
+
+    private static bool TryDecodePayload(string encoded, ChainProfile profile, bool isPrivate,
+        out byte[]? payload, out ScriptKind kind)
+    {
+        payload = null;
+        kind = default;
+        if (string.IsNullOrWhiteSpace(encoded))
+            return false;
+
+        byte[] data;
+        try
+        {
+            data = Encoders.Base58Check.DecodeData(encoded.Trim());
+        }
+        catch (FormatException)
+        {
+            return false;
+        }
+
+        if (data.Length != 78)
+            return false;
+
+        var header = (uint)(data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3]);
+        foreach (var (candidate, headers) in profile.ExtKeyHeaders)
+        {
+            if (header != (isPrivate ? headers.Private : headers.Public))
+                continue;
+            kind = candidate;
+            payload = data[4..];
+            return true;
+        }
+
+        return false;
+    }
+}