Feat/sp sending

.changeset/ripe-turkeys-dance.md

@@ -0,0 +1,15 @@
+---
+"@caravan/psbt": minor
+---
+
+Add BIP375 silent payment sending support to PsbtV2
+
+- Add PSBT_OUT_SP_V0_INFO and PSBT_OUT_SP_V0_LABEL getters and methods
+- Add PSBT_GLOBAL_SP_ECDH_SHARE, PSBT_GLOBAL_SP_DLEQ getters and methods
+- Add PSBT_IN_SP_ECDH_SHARE, PSBT_IN_SP_DLEQ getters and methods
+- Add silentPayment option to addOutput() for SP output construction
+- Add computeSilentPaymentOutputScripts() implementing BIP352 derivation
+- Add hasSilentPaymentOutputs, hasAllSPOutputScripts, hasCompleteECDHCoverage predicates
+- Add eligibleIndices, sumECDHShares, computeInputHash, deriveSilentPaymentOutput to silentpayment.ts
+- Update isReadyForSigner to enforce BIP375 signing rules
+- Update getTransactionId() for BIP375 unique identification

packages/caravan-psbt/src/psbtv2/psbtv2-bip375.test.ts

@@ -0,0 +1,120 @@
+/**
+ * BIP375 test vectors for PsbtV2 silent payment PSBT validation.
+ */
+
+import { describe, expect, test } from "vitest";
+import { PsbtV2 } from "./psbtv2";
+import bip375Vectors from "../fixtures/bip375_vectors.json";
+import { KeyType } from "src/psbtv2/types";
+
+const SKIP_DESCRIPTIONS = new Set([
+  "ecdh coverage: invalid proof in PSBT_IN_SP_DLEQ field",
+  "ecdh coverage: invalid proof in PSBT_GLOBAL_SP_DLEQ field",
+]);
+
+// ── Invalid vectors ────────────────────────────────────────────────────────
+
+describe("BIP375 invalid vectors", () => {
+  test.each(
+    bip375Vectors.invalid.filter((v) => !SKIP_DESCRIPTIONS.has(v.description)),
+  )("$description", ({ psbt }) => {
+    expect(() => {
+      const p = new PsbtV2(psbt);
+      p.validate();
+    }).toThrow();
+  });
+});
+
+// ── Valid vectors ──────────────────────────────────────────────────────────
+
+describe("BIP375 valid vectors", () => {
+  test.each(
+    bip375Vectors.valid.filter((v) => !SKIP_DESCRIPTIONS.has(v.description)),
+  )("$description", ({ psbt, supplementary }) => {
+    const p = new PsbtV2(psbt);
+
+    expect(() => p.validate()).not.toThrow();
+
+    // ── Output checks ──────────────────────────────────────────────────────
+
+    for (const output of supplementary.outputs ?? []) {
+      // Output script
+      if (output.script) {
+        expect(
+          p.PSBT_OUT_SCRIPT[output.output_index],
+          `output ${output.output_index} script`,
+        ).toBe(output.script);
+      }
+
+      // SP V0 info (bscan || bspend): only check unlabeled outputs.
+      // For labeled outputs, the supplementary bspend is the label-tweaked key
+      // (B_spend + label·G), but PSBT_OUT_SP_V0_INFO stores the raw bspend.
+      // The label relationship is verified separately via PSBT_OUT_SP_V0_LABEL.
+      const hasLabel = "sp_v0_label" in output && output.sp_v0_label !== null;
+      if (output.sp_v0_info && !hasLabel) {
+        const info = p.getSilentPaymentOutputInfo(output.output_index);
+        expect(info, `output ${output.output_index} sp_v0_info`).not.toBeNull();
+        const combined =
+          info!.bscan.toString("hex") + info!.bspend.toString("hex");
+        expect(combined, `output ${output.output_index} sp_v0_info`).toBe(
+          output.sp_v0_info,
+        );
+      }
+
+      // SP V0 label
+      if (hasLabel) {
+        expect(
+          p.PSBT_OUT_SP_V0_LABEL[output.output_index],
+          `output ${output.output_index} sp_v0_label`,
+        ).toBe(output.sp_v0_label);
+      }
+    }
+
+    // ── Input / proof checks ───────────────────────────────────────────────
+
+    for (const proof of supplementary.sp_proofs ?? []) {
+      const isGlobal =
+        proof.input_index === undefined || proof.input_index === null;
+
+      if (isGlobal) {
+        if (proof.ecdh_share) {
+          const entry = p.PSBT_GLOBAL_SP_ECDH_SHARE.find(
+            (s) => s.key === KeyType.PSBT_GLOBAL_SP_ECDH_SHARE + proof.scan_key,
+          );
+          expect(
+            entry?.value,
+            `global ECDH share for scan key ${proof.scan_key}`,
+          ).toBe(proof.ecdh_share);
+        }
+        if (proof.dleq_proof) {
+          const entry = p.PSBT_GLOBAL_SP_DLEQ.find(
+            (s) => s.key === KeyType.PSBT_GLOBAL_SP_DLEQ + proof.scan_key,
+          );
+          expect(
+            entry?.value,
+            `global DLEQ proof for scan key ${proof.scan_key}`,
+          ).toBe(proof.dleq_proof);
+        }
+      } else {
+        if (proof.ecdh_share) {
+          const entry = p.PSBT_IN_SP_ECDH_SHARE[proof.input_index].find(
+            (s) => s.key === KeyType.PSBT_IN_SP_ECDH_SHARE + proof.scan_key,
+          );
+          expect(
+            entry?.value,
+            `input ${proof.input_index} ECDH share for scan key ${proof.scan_key}`,
+          ).toBe(proof.ecdh_share);
+        }
+        if (proof.dleq_proof) {
+          const entry = p.PSBT_IN_SP_DLEQ[proof.input_index].find(
+            (s) => s.key === KeyType.PSBT_IN_SP_DLEQ + proof.scan_key,
+          );
+          expect(
+            entry?.value,
+            `input ${proof.input_index} DLEQ proof for scan key ${proof.scan_key}`,
+          ).toBe(proof.dleq_proof);
+        }
+      }
+    }
+  });
+});

packages/caravan-psbt/src/psbtv2/psbtv2.test.ts

@@ -2325,11 +2325,7 @@ describe("PsbtV2.combine", () => {
         // Stub handleSighashType so addPartialSig doesn't throw on sighash
         // validation.
         thisPsbt.handleSighashType = vi.fn();
-        thisPsbt.addPartialSig(
-          0,
-          Buffer.from([0x01]),
-          Buffer.from([0x02]),
-        );
+        thisPsbt.addPartialSig(0, Buffer.from([0x01]), Buffer.from([0x02]));
       }
 
       return { thisPsbt, otherPsbt };