From 9c72e7a2b48148b6847268fec1215ce4deab5764 Mon Sep 17 00:00:00 2001
From: jlest01 <174762002+jlest01@users.noreply.github.com>
Date: Thu, 1 Aug 2024 23:53:19 -0300
Subject: [PATCH] Add `silentpayments_test_outputs`

---
 examples/silentpayments.c              | 29 ++++++++++++++-----
 include/secp256k1_silentpayments.h     |  3 +-
 src/modules/silentpayments/main_impl.h | 40 +++++---------------------
 3 files changed, 30 insertions(+), 42 deletions(-)

diff --git a/examples/silentpayments.c b/examples/silentpayments.c
index 9777b47279..b2301212f4 100644
--- a/examples/silentpayments.c
+++ b/examples/silentpayments.c
@@ -111,10 +111,9 @@ const unsigned char* label_lookup(
 }
 
 int main(void) {
-    enum { N_TX_INPUTS = 2, N_TX_OUTPUTS = 3, N_OUT_PUBKEYS = 198 };
+    enum { N_TX_INPUTS = 2, N_TX_OUTPUTS = 3 };
 
-    int n_out_pubkeys = N_OUT_PUBKEYS;
-    unsigned char out_pubkeys[N_OUT_PUBKEYS];
+    secp256k1_xonly_pubkey out_pubkeys[N_TX_OUTPUTS];
 
     unsigned char randomize[32];
     unsigned char xonly_print[32];
@@ -227,13 +226,29 @@ int main(void) {
             ctx, 
             recipients, 
             N_TX_OUTPUTS, 
-            out_pubkeys, 
-            n_out_pubkeys
+            out_pubkeys
         );
         assert(ret);
 
-        printf("out_pubkeys: ");
-        print_hex(out_pubkeys, n_out_pubkeys);
+        for (i = 0; i < N_TX_OUTPUTS; i++) {
+            unsigned char serialized_pubkey[33];
+            unsigned char serialized_xonly_pubkey[32];
+            size_t len;
+
+            len = 33;
+            ret = secp256k1_ec_pubkey_serialize(ctx, serialized_pubkey, &len, &recipients[i].scan_pubkey, SECP256K1_EC_COMPRESSED);
+
+            ret = secp256k1_xonly_pubkey_serialize(ctx, serialized_xonly_pubkey, &out_pubkeys[i]);
+            assert(ret);
+
+            printf("Output %li:\n", i);
+            print_hex(serialized_pubkey, 33);
+            print_hex(serialized_xonly_pubkey, 32);            
+        }
+        
+
+        /* printf("out_pubkeys: ");
+        print_hex(out_pubkeys, n_out_pubkeys); */
         
         ret = secp256k1_silentpayments_sender_create_outputs(ctx,
             generated_output_ptrs,
diff --git a/include/secp256k1_silentpayments.h b/include/secp256k1_silentpayments.h
index b280309a25..46cd021fdf 100644
--- a/include/secp256k1_silentpayments.h
+++ b/include/secp256k1_silentpayments.h
@@ -111,8 +111,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_silentpayments_test_out
     const secp256k1_context *ctx,
     const secp256k1_silentpayments_recipient *recipients,
     size_t n_recipients,
-    unsigned char *out_pubkeys,
-    size_t n_out_pubkeys
+    secp256k1_xonly_pubkey *generated_outputs
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);
 
 /** Create Silent Payment label tweak and label.
diff --git a/src/modules/silentpayments/main_impl.h b/src/modules/silentpayments/main_impl.h
index f79ef55ce5..e7f486f42e 100644
--- a/src/modules/silentpayments/main_impl.h
+++ b/src/modules/silentpayments/main_impl.h
@@ -152,50 +152,24 @@ int secp256k1_silentpayments_test_outputs(
     const secp256k1_context *ctx,
     const secp256k1_silentpayments_recipient *recipients,
     size_t n_recipients,
-    unsigned char *out_pubkeys,
-    size_t n_out_pubkeys
+    secp256k1_xonly_pubkey *generated_outputs
 ) {
     size_t i;
     int ret = 1;
     
-    VERIFY_CHECK(n_out_pubkeys == 66 * n_recipients);
-    
     for (i = 0; i < n_recipients; i++) {
         ARG_CHECK(recipients[i].index == i);
     }
 
-    /* Initialize out_pubkeys to zero */
-    memset(out_pubkeys, 0, n_out_pubkeys);
-
     for (i = 0; i < n_recipients; i++) {
-        unsigned char *compressed_scan_pubkey = &out_pubkeys[i * 66];
-        unsigned char *compressed_spend_pubkey = &out_pubkeys[i * 66 + 33];
-
-        size_t len;
-
-        // printf("index: %ld\n", recipients[i].index);
-
-        /* Serialize pubkey1 in a compressed form (33 bytes), should always return 1 */
-        len = 33;
-        ret = secp256k1_ec_pubkey_serialize(ctx, compressed_scan_pubkey, &len, &recipients[i].scan_pubkey, SECP256K1_EC_COMPRESSED);
-        /* Should be the same size as the size of the output, because we passed a 33 byte array. */
-        VERIFY_CHECK(len == 33);
-
-        len = 33;
-        ret = secp256k1_ec_pubkey_serialize(ctx, compressed_spend_pubkey, &len, &recipients[i].spend_pubkey, SECP256K1_EC_COMPRESSED);
-        /* Should be the same size as the size of the output, because we passed a 33 byte array. */
-        VERIFY_CHECK(len == 33);
-
-        // printf("scan_pubkey: ");
-        // print_hex(compressed_scan_pubkey, 33);
-
-        // printf("spend_pubkey: ");
-        // print_hex(compressed_spend_pubkey, 33);
-
+        secp256k1_xonly_pubkey new_xonly_pubkey;
+        ret = secp256k1_xonly_pubkey_from_pubkey(ctx, &new_xonly_pubkey, NULL, &recipients[i].scan_pubkey);
+        if (!ret) {
+            return 0;
+        }
+        generated_outputs[i] = new_xonly_pubkey;
     }
 
-    VERIFY_CHECK((i * 66) == n_out_pubkeys);
-
     return ret;
 }