- Make message public key sharing mandatory for messages that are encrypted and where both keys are known. For EncryptedInvoiceRequest, only the sender_public_key is required

- Add nonce to EncryptedPaymentRequest, EncryptedPayment and EncryptedPaymentACK
- Update ECDH instruction to allow for the current message instead of an InvoiceRequest to contain the nonce
- Updated paymentrequest.proto with BIP definition changes

bip-ir/paymentrequest.proto

@@ -46,11 +46,6 @@ message PaymentACK {
 }
 
 // BIP-IR Extensions
-message EncryptedInvoiceRequest {
-        required bytes encrypted_invoice_request = 1;   // AES-256-CBC Encrypted InvoiceRequest as defined in InvoiceRequest Spec
-        required bytes sender_public_key = 2;           // Sender's EC Public Key
-        required bytes invoice_request_hash = 3;        // SHA256 Hash of Non-Encrypted, Serialized InvoiceRequest (used for authentication)
-}
 
 message InvoiceRequest {
         required bytes  sender_public_key = 1;              // Sender's EC Public Key
@@ -63,22 +58,42 @@ message InvoiceRequest {
         optional bytes  signature = 8;                      // PKI-dependent signature
 }
 
+message EncryptedInvoiceRequest {
+        required bytes  encrypted_invoice_request = 1;      // AES-256-CBC Encrypted InvoiceRequest as defined in InvoiceRequest Spec
+        required bytes  invoice_request_hash = 2;           // SHA256 Hash of Non-Encrypted, Serialized InvoiceRequest (used for authentication)
+        required bytes  sender_public_key = 3;              // Sender's EC Public Key
+        optional bytes  receiver_public_key = 4;            // Receiver's EC Public Key
+        required uint64 nonce = 5;                          // Microseconds since epoch
+        optional bytes  identifier = 6;                     // Unique key to identify this entire exchange on the server. invoice_request_hash SHOULD be used by default
+}
+
 message EncryptedPaymentRequest {
-        required bytes encrypted_payment_request = 1;                   // AES-256-CBC Encrypted PaymentRequest as defined in InvoiceRequest Spec
-        required bytes receiver_public_key = 2;                         // Receiver's EC Public Key
-        required bytes ephemeral_public_key = 3;                        // Public Key of ECDH-derived keypair
-        required bytes payment_request_hash = 4;                        // SHA256 Hash of Non-Encrypted, Serialized PaymentRequest (used for authentication)
-        required bool  requires_payment_message = 5 [default = false];  // Requires Payment/PaymentACK message exchange
+        required bytes  encrypted_payment_request = 1;                   // AES-256-CBC Encrypted PaymentRequest as defined in InvoiceRequest Spec
+        required bytes  payment_request_hash = 2;                        // SHA256 Hash of Non-Encrypted, Serialized PaymentRequest (used for authentication)
+        required bytes  receiver_public_key = 3;                         // Receiver's EC Public Key
+        required bytes  sender_public_key = 4;                           // Sender's EC Public Key
+        required uint64 nonce = 5;                                       // Microseconds since epoch
+        optional bool   requires_payment_message = 6 [default = false];  // Requires Payment/PaymentACK message exchange
+        optional bytes  signature = 7;                                   // Signature of this message using Receiver's EC key
+        optional bytes  identifier = 8;                                  // MUST use the identifier specified with the InvoiceRequest if the PaymentRequest is in response to an InvoiceRequest. Otherwise, use payment_request_hash or other unique value.
 }
 
 message EncryptedPayment {
-        required bytes encrypted_payment = 1;           // AES-256-CBC Encrypted Payment as defined in InvoiceRequest Spec
-        required bytes payment_request_hash = 2;        // SHA256 Hash of Non-Encrypted, Serialized PaymentRequest returned in the transaction's EncryptedPaymentRequest message
-        required bytes signature = 3;                   // Signature over EncryptedPayment with original Sender's EC Private Key
+        required bytes  encrypted_payment = 1;           // AES-256-CBC Encrypted BIP70 Payment as defined in InvoiceRequest Spec
+        required bytes  payment_hash = 2;                // SHA256 Hash of Non-Encrypted, Serialized BIP70 Payment
+        required bytes  receiver_public_key = 3;         // Receiver's EC Public Key
+        required bytes  sender_public_key = 4;           // Sender's EC Public Key
+        required uint64 nonce = 5;                       // Microseconds since epoch
+        required bytes  signature = 6;                   // Signature over EncryptedPayment with Sender's EC Key
+        optional bytes  identifier = 7;                  // Use the identifier specified with the EncryptedPaymentRequest, if any.
 }
 
 message EncryptedPaymentACK {
-        required bytes encrypted_payment_ack = 1;       // AES-256-CBC Encrypted Payment as defined in InvoiceRequest Spec
-        required bytes payment_request_hash = 2;        // SHA256 Hash of Non-Encrypted, Serialized PaymentRequest returned in the transaction's EncryptedPaymentRequest message
-        required bytes signature = 3;                   // Signature over EncryptedPaymentACK with the Receiver's EC Private key.
-}
+        required bytes  encrypted_payment_ack = 1;       // AES-256-CBC Encrypted BIP70 PaymentACK as defined in InvoiceRequest Spec
+        required bytes  payment_ack_hash = 2;            // SHA256 Hash of Non-Encrypted, Serialized BIP70 PaymentACK
+        required bytes  receiver_public_key = 3;         // Receiver's EC Public Key
+        required bytes  sender_public_key = 4;           // Sender's EC Public Key
+        required uint64 nonce = 5;                       // Microseconds since epoch
+        required bytes  signature = 6;                   // Signature over EncryptedPaymentACK with Receiver's EC Key
+        optional bytes  identifier = 7;                  // Use the identifier specified with the EncryptedPaymentRequest, if any.
+}