Add an encryption key to ExpandedKey for Offers

[rust-lightning] / lightning / src / ln / inbound_payment.rs

diff --git a/lightning/src/ln/inbound_payment.rs b/lightning/src/ln/inbound_payment.rs
index e01cdf364eb175fd6fc503e3a9d24cda5e046ee4..956928fd7fa008c89de4713aa78586060ba635c6 100644 (file)
--- a/lightning/src/ln/inbound_payment.rs
+++ b/lightning/src/ln/inbound_payment.rs
@@ -19,7 +19,7 @@ use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 use crate::ln::msgs;
 use crate::ln::msgs::MAX_VALUE_MSAT;
 use crate::util::chacha20::ChaCha20;
-use crate::util::crypto::hkdf_extract_expand_4x;
+use crate::util::crypto::hkdf_extract_expand_5x;
 use crate::util::errors::APIError;
 use crate::util::logger::Logger;
 
@@ -50,6 +50,8 @@ pub struct ExpandedKey {
        user_pmt_hash_key: [u8; 32],
        /// The base key used to derive signing keys and authenticate messages for BOLT 12 Offers.
        offers_base_key: [u8; 32],
+       /// The key used to encrypt message metadata for BOLT 12 Offers.
+       offers_encryption_key: [u8; 32],
 }
 
 impl ExpandedKey {
@@ -57,13 +59,19 @@ impl ExpandedKey {
        ///
        /// It is recommended to cache this value and not regenerate it for each new inbound payment.
        pub fn new(key_material: &KeyMaterial) -> ExpandedKey {
-               let (metadata_key, ldk_pmt_hash_key, user_pmt_hash_key, offers_base_key) =
-                       hkdf_extract_expand_4x(b"LDK Inbound Payment Key Expansion", &key_material.0);
+               let (
+                       metadata_key,
+                       ldk_pmt_hash_key,
+                       user_pmt_hash_key,
+                       offers_base_key,
+                       offers_encryption_key,
+               ) = hkdf_extract_expand_5x(b"LDK Inbound Payment Key Expansion", &key_material.0);
                Self {
                        metadata_key,
                        ldk_pmt_hash_key,
                        user_pmt_hash_key,
                        offers_base_key,
+                       offers_encryption_key,
                }
        }