init

include/xrpl/protocol/detail/features.macro

@@ -34,6 +34,7 @@
 // If you add an amendment here, then do not forget to increment `numFeatures`
 // in include/xrpl/protocol/Feature.h.
 
+XRPL_FEATURE(SecureUI,                   Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FIX    (HookMap,                    Supported::yes, VoteBehavior::DefaultYes)
 XRPL_FIX    (GuardDepth32,               Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(NamedHooks,                 Supported::yes, VoteBehavior::DefaultNo)

include/xrpl/protocol/detail/ledger_entries.macro

@@ -262,6 +262,7 @@ LEDGER_ENTRY(ltACCOUNT_ROOT, 0x0061, AccountRoot, account, ({
     {sfHookStateScale,       soeOPTIONAL},
     {sfCron,                 soeOPTIONAL},
     {sfAMMID,                soeOPTIONAL},
+    {sfSecureUI,             soeOPTIONAL},
 }))
 
 /** A ledger object which contains a list of object identifiers.

include/xrpl/protocol/detail/sfields.macro

@@ -293,6 +293,7 @@ TYPED_SFIELD(sfAssetClass,               VL,        29)
 TYPED_SFIELD(sfProvider,                 VL,        30)
 TYPED_SFIELD(sfMPTokenMetadata,          VL,        31)
 TYPED_SFIELD(sfCredentialType,           VL,        32)
+TYPED_SFIELD(sfSecureUI,                 VL,        96)
 TYPED_SFIELD(sfHookName,                 VL,        97)
 TYPED_SFIELD(sfRemarkValue,              VL,        98)
 TYPED_SFIELD(sfRemarkName,               VL,        99)

include/xrpl/protocol/detail/transactions.macro

@@ -74,6 +74,7 @@ TRANSACTION(ttACCOUNT_SET, 3, AccountSet, ({
     {sfTickSize, soeOPTIONAL},
     {sfNFTokenMinter, soeOPTIONAL},
     {sfHookStateScale, soeOPTIONAL},
+    {sfSecureUI, soeOPTIONAL},
 }))
 
 /** This transaction type cancels an existing escrow. */

src/xrpld/app/tx/detail/SetAccount.cpp

@@ -197,6 +197,31 @@ SetAccount::preflight(PreflightContext const& ctx)
             return temMALFORMED;
     }
 
+    if (tx.isFieldPresent(sfSecureUI))
+    {
+        if (!ctx.rules.enabled(featureSecureUI))
+            return temMALFORMED;
+
+        Blob ui = tx.getFieldVL(sfSecureUI);
+
+        if (ui.size() == 0)
+        {
+            // this is an unset operation, pass
+        }
+        else if (ui.size() > 4096)
+        {
+            JLOG(j.trace()) << "SecureUI: Too long > 4096 bytes";
+            return temMALFORMED;
+        }
+        else if (!URIToken::validateUTF8(ui))
+        {
+            JLOG(j.trace()) << "SecureUI: Not UTF-8";
+            return temMALFORMED;
+        }
+
+        // valid
+    } 
+
     return preflight2(ctx);
 }
 
@@ -699,6 +724,23 @@ SetAccount::doApply()
             sle->setFieldU16(sfHookStateScale, newScale);
         }
     }
+
+    if (tx.isFieldPresent(sfSecureUI))
+    {
+        Blob ui = tx.getFieldVL(sfSecureUI);
+        if (ui.size() == 0)
+        {
+            // unset operation
+            if (sle->isFieldPresent(sfSecureUI))
+                sle->makeFieldAbsent(sfSecureUI);
+        }
+        else
+        {
+            // set operation
+            sle->setFieldVL(sfSecureUI, std::move(ui));
+        }
+    }
+
     ctx_.view().update(sle);
 
     return tesSUCCESS;