diff --git a/nostr_core/cashu_mint.c b/nostr_core/cashu_mint.c
index 393f8419..e8bdf161 100644
--- a/nostr_core/cashu_mint.c
+++ b/nostr_core/cashu_mint.c
@@ -1632,12 +1632,26 @@ static int cashu_encode_token_b(const cashu_decoded_token_t* token,
     if (rc != NOSTR_SUCCESS) goto fail;
 
     const char* inherited_id = token->proofs[0].id;
+    size_t inherited_id_hex_len = inherited_id ? strlen(inherited_id) : 0;
+    if (!inherited_id || inherited_id_hex_len == 0 || (inherited_id_hex_len % 2) != 0 ||
+        !cashu_is_hex_string_len(inherited_id, inherited_id_hex_len) ||
+        inherited_id_hex_len > (NOSTR_CASHU_KEYSET_ID_HEX_SIZE - 1)) {
+        rc = NOSTR_ERROR_INVALID_INPUT;
+        goto fail;
+    }
+
+    unsigned char inherited_id_bytes[(NOSTR_CASHU_KEYSET_ID_HEX_SIZE - 1) / 2] = {0};
+    size_t inherited_id_byte_len = inherited_id_hex_len / 2;
+    if (nostr_hex_to_bytes(inherited_id, inherited_id_bytes, inherited_id_byte_len) != 0) {
+        rc = NOSTR_ERROR_INVALID_INPUT;
+        goto fail;
+    }
 
     rc = cashu_cbor_write_type_uint(&b, 5, 2);
     if (rc != NOSTR_SUCCESS) goto fail;
     rc = cashu_cbor_write_text(&b, "i");
     if (rc != NOSTR_SUCCESS) goto fail;
-    rc = cashu_cbor_write_text(&b, inherited_id);
+    rc = cashu_cbor_write_bytes(&b, inherited_id_bytes, inherited_id_byte_len);
     if (rc != NOSTR_SUCCESS) goto fail;
 
     rc = cashu_cbor_write_text(&b, "p");
@@ -1655,9 +1669,24 @@ static int cashu_encode_token_b(const cashu_decoded_token_t* token,
         if (rc != NOSTR_SUCCESS) goto fail;
 
         if (has_local_id) {
+            size_t local_id_hex_len = p->id ? strlen(p->id) : 0;
+            if (!p->id || local_id_hex_len == 0 || (local_id_hex_len % 2) != 0 ||
+                !cashu_is_hex_string_len(p->id, local_id_hex_len) ||
+                local_id_hex_len > (NOSTR_CASHU_KEYSET_ID_HEX_SIZE - 1)) {
+                rc = NOSTR_ERROR_INVALID_INPUT;
+                goto fail;
+            }
+
+            unsigned char local_id_bytes[(NOSTR_CASHU_KEYSET_ID_HEX_SIZE - 1) / 2] = {0};
+            size_t local_id_byte_len = local_id_hex_len / 2;
+            if (nostr_hex_to_bytes(p->id, local_id_bytes, local_id_byte_len) != 0) {
+                rc = NOSTR_ERROR_INVALID_INPUT;
+                goto fail;
+            }
+
             rc = cashu_cbor_write_text(&b, "i");
             if (rc != NOSTR_SUCCESS) goto fail;
-            rc = cashu_cbor_write_text(&b, p->id);
+            rc = cashu_cbor_write_bytes(&b, local_id_bytes, local_id_byte_len);
             if (rc != NOSTR_SUCCESS) goto fail;
         }
 
@@ -1671,17 +1700,15 @@ static int cashu_encode_token_b(const cashu_decoded_token_t* token,
             goto fail;
         }
 
-        unsigned char secret_bytes[32] = {0};
         unsigned char C_bytes[33] = {0};
-        if (nostr_hex_to_bytes(p->secret, secret_bytes, 32) != 0 ||
-            nostr_hex_to_bytes(p->C, C_bytes, 33) != 0) {
+        if (nostr_hex_to_bytes(p->C, C_bytes, 33) != 0) {
             rc = NOSTR_ERROR_INVALID_INPUT;
             goto fail;
         }
 
         rc = cashu_cbor_write_text(&b, "s");
         if (rc != NOSTR_SUCCESS) goto fail;
-        rc = cashu_cbor_write_bytes(&b, secret_bytes, sizeof(secret_bytes));
+        rc = cashu_cbor_write_text(&b, p->secret);
         if (rc != NOSTR_SUCCESS) goto fail;
 
         rc = cashu_cbor_write_text(&b, "c");