support ConfidentialSend (#5921)

include/xrpl/protocol/ConfidentialTransfer.h

@@ -133,6 +133,9 @@ serializeEcPair(
 TER
 homomorphicAdd(Slice const& a, Slice const& b, Buffer& out);
 
+TER
+homomorphicSubtract(Slice const& a, Slice const& b, Buffer& out);
+
 TER
 proveEquality(
     Slice const& proof,
@@ -150,6 +153,20 @@ encryptCanonicalZeroAmount(
     Slice const& pubKeySlice,
     AccountID const& account,
     MPTID const& mptId);
+
+TER
+verifyConfidentialSendProof(
+    Slice const& proof,
+    Slice const& encSenderBalance,
+    Slice const& encSenderAmt,
+    Slice const& encDestAmt,
+    Slice const& encIssuerAmt,
+    Slice const& senderPubKey,
+    Slice const& destPubKey,
+    Slice const& issuerPubKey,
+    std::uint32_t const version,
+    uint256 const& txHash);
+
 }  // namespace ripple
 
 #endif

include/xrpl/protocol/detail/sfields.macro

@@ -294,6 +294,8 @@ TYPED_SFIELD(sfHolderElGamalPublicKey,   VL,        36)
 TYPED_SFIELD(sfZKProof,                  VL,        37)
 TYPED_SFIELD(sfHolderEncryptedAmount,    VL,        38)
 TYPED_SFIELD(sfIssuerEncryptedAmount,    VL,        39)
+TYPED_SFIELD(sfSenderEncryptedAmount,    VL,        40)
+TYPED_SFIELD(sfDestinationEncryptedAmount, VL,      41)
 
 // account (common)
 TYPED_SFIELD(sfAccount,                  ACCOUNT,    1)

include/xrpl/protocol/detail/transactions.macro

@@ -990,6 +990,22 @@ TRANSACTION(ttCONFIDENTIAL_CONVERT_BACK, 74, ConfidentialConvertBack,
     {sfZKProof, soeREQUIRED},
 }))
 
+#if TRANSACTION_INCLUDE
+#include <xrpld/app/tx/detail/ConfidentialSend.h>
+#endif
+TRANSACTION(ttCONFIDENTIAL_SEND, 75, ConfidentialSend,
+    Delegation::delegatable,
+    featureConfidentialTransfer,
+    noPriv,
+    ({
+    {sfMPTokenIssuanceID, soeREQUIRED},
+    {sfDestination, soeREQUIRED},
+    {sfSenderEncryptedAmount, soeREQUIRED},
+    {sfDestinationEncryptedAmount, soeREQUIRED},
+    {sfIssuerEncryptedAmount, soeREQUIRED},
+    {sfZKProof, soeREQUIRED},
+}))
+
 /** This system-generated transaction type is used to update the status of the various amendments.
 
     For details, see: https://xrpl.org/amendments.html