Add XLS-55d: 0055 XLS-55d: Remit: Atomic Multi-Asset Payments for XRPL Protocol Chains (#347)

* Add XLS-55d: 0055 XLS-55d: Remit: Atomic Multi-Asset Payments for  XRPL Protocol Chains

Author: mvadari

XLS-0055-remit/README.md

@@ -0,0 +1,97 @@
+<pre>
+  xls: 55
+  title: Remit
+  description: Atomic Multi-Asset Payments for XRPL Protocol Chains
+  author: Richard Holland (@RichardAH)
+  created: 2023-12-03
+  status: Final
+  category: Amendment
+</pre>
+
+## Introduction
+
+**_Remit_** is a new payment transactor designed for XRPL Protocol Chains, which allows a sender to send multiple currencies and tokens atomically to a specified destination. It is a push payment that delivers "no matter what" and is designed for retail and Hooks use-cases.
+
+## Constraints
+
+Using _Remit_ the sender may send:
+
+- one or more Issued Currencies, and/or,
+- one or more pre-existing URITokens owned by the sender and/or,
+- one new URIToken created in-line as part of the transaction.
+
+The transactor has the following behaviours:
+
+- If the destination does not exist, the sender pays to create it.
+- If the destination does not have the required trust-lines, the sender pays to create these.
+- The exact amounts and tokens are always delivered as specified in the transaction, if validated with code tesSUCCESS.
+- The sender pays all transfer fees on currencies, and the fees are not subtracted from the sent amount.
+- Where the sender pays to create objects, this is a separate amount not taken from the amounts specified in the transaction.
+- The transaction is atomic, either all amounts and tokens are delivered in the exact specified amount or none of them are.
+- The transactor does no conversion or pathing, the sender must already have the balances and tokens they wish to send.
+- When no amounts or tokens are specified, the transaction may still succeed. This can be used to create an account or ensure an account already exists.
+
+## Specification
+
+A _Remit_ transaction contains the following fields:
+Field | Required | Type | Description
+-|-|-|-
+sfAccount | ✅ |AccountID | The sender
+sfDestination | ✅ |AccountID | The recipient. Does not need to exist. Will be created if doesn't exist.
+sfDestinationTag | ❌ |UInt32 | May be used by the destination to differentiate sub-accounts.
+sfAmounts | ❌|Array of Amounts | Each of the currencies (if any) to send to the destination. Sender must have funded trustlines for each. Destination does not need trustlines.
+sfURITokenIDs | ❌| Array of URITokenIDs | Each of the URITokens (if any) to send to the destination.
+sfMintURIToken | ❌| URIToken | If included, an inline URIToken to be created and delivered to the destination, for example a receipt.
+sfBlob | ❌ | Blob | A hex blob up to 128 kib to supply to a receiving Hook at the destination.
+sfInform | ❌ | AccountID | A third party. If supplied, their Hooks will be weakly executed (but the sender will pay for that execution).
+sfInvoiceID | ❌ | UInt256 | An arbitrary identifier for this remittance.
+
+## Example Transaction
+
+```
+{
+      "TransactionType" : "Remit",
+      "Account" : "rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh",
+      "Destination" : "raod38dcxe6AGWfqxtZjPUfUdyrkWDe7d",
+      "Amounts" : [
+         {
+            "AmountEntry" : {
+               "Amount" : "123"
+            }
+         },
+         {
+            "AmountEntry" : {
+               "Amount" : {
+                  "currency" : "USD",
+                  "issuer" : "rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh",
+                  "value" : "10"
+               }
+            }
+         },
+         {
+            "AmountEntry" : {
+               "Amount" : {
+                  "currency" : "ABC",
+                  "issuer" : "rpfZurEGaJvpioTaxYpjh1EAtMXFN1HdtB",
+                  "value" : "12"
+               }
+            }
+         }
+      ],
+      "URITokenIDs" : [
+         "C24DAF43927556F379F7B8616176E57ACEFF1B5D016DC896222603A6DD11CE05",
+         "5E69C2D692E12D615B5FAC4A41989DA1EA5FD36E8F869B9ECA1121F561E33D2A"
+      ],
+      "MintURIToken" : {
+         "URI" : "68747470733A2F2F736F6D652E757269"
+      }
+}
+```
+
+## Unwanted Remits
+
+Users who do not want to receive _Remit_ transactions can either set the _asfDisallowIncomingRemit_ on their accounts or install a Hook that will regulate incoming Remits. Alternatively they can simply burn unwanted URITokens or return unwanted Issued Currencies in order to claim the reserve that was paid by the sender.
+
+## Chain Requirements
+
+XLS-55 depends on the adoption of XLS-35 on the applicable chain.