Drop need to store pending inbound payments

and replace payment_secret with encrypted metadata

See docs on verify_inbound_payment for details

lightning/src/chain/keysinterface.rs

@@ -40,7 +40,7 @@ use ln::script::ShutdownScript;
 
 use prelude::*;
 use core::sync::atomic::{AtomicUsize, Ordering};
-use io::{self, Error};
+use io::{self, Error, Read};
 use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 
 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
@@ -49,6 +49,19 @@ use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
 pub struct KeyMaterial(pub [u8;32]);
 
+impl Writeable for KeyMaterial {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+		self.0.write(w)
+	}
+}
+
+impl Readable for KeyMaterial {
+	fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+		let buf: [u8; 32] = Readable::read(r)?;
+		Ok(KeyMaterial(buf))
+	}
+}
+
 /// Information about a spendable output to a P2WSH script. See
 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
 #[derive(Clone, Debug, PartialEq)]