feat: Add SIGN_MODE_DIRECT_AUX and tx Tip proto definitions (cosmos#9405

)

closes: cosmos#9406 

---

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- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
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docs/core/proto-docs.md

@@ -611,8 +611,10 @@
     - [ModeInfo.Multi](#cosmos.tx.v1beta1.ModeInfo.Multi)
     - [ModeInfo.Single](#cosmos.tx.v1beta1.ModeInfo.Single)
     - [SignDoc](#cosmos.tx.v1beta1.SignDoc)
+    - [SignDocDirectAux](#cosmos.tx.v1beta1.SignDocDirectAux)
     - [SignDocJSON](#cosmos.tx.v1beta1.SignDocJSON)
     - [SignerInfo](#cosmos.tx.v1beta1.SignerInfo)
+    - [Tip](#cosmos.tx.v1beta1.Tip)
     - [Tx](#cosmos.tx.v1beta1.Tx)
     - [TxBody](#cosmos.tx.v1beta1.TxBody)
     - [TxRaw](#cosmos.tx.v1beta1.TxRaw)
@@ -8623,7 +8625,8 @@ SignMode represents a signing mode with its own security guarantees.
 | SIGN_MODE_UNSPECIFIED | 0 | SIGN_MODE_UNSPECIFIED specifies an unknown signing mode and will be rejected. |
 | SIGN_MODE_DIRECT | 1 | SIGN_MODE_DIRECT specifies a signing mode which uses SignDoc and is verified with raw bytes from Tx. |
 | SIGN_MODE_TEXTUAL | 2 | SIGN_MODE_TEXTUAL is a future signing mode that will verify some human-readable textual representation on top of the binary representation from SIGN_MODE_DIRECT. It is currently not supported. |
-| SIGN_MODE_DIRECT_JSON | 3 | SIGN_MODE_DIRECT_JSON specifies a signing mode which uses SignDocJSON. It is verified using a canonical JSON representation of the bytes used in SIGN_MODE_DIRECT. |
+| SIGN_MODE_DIRECT_JSON | 3 | SIGN_MODE_DIRECT_JSON specifies a signing mode which uses SignDocJSON. It is verified using a canonical JSON representation of the bytes used in SIGN_MODE_DIRECT. It is currently not supported. |
+| SIGN_MODE_DIRECT_AUX | 4 | SIGN_MODE_DIRECT_AUX specifies a signing mode which uses SignDocDirectAux. As opposed to SIGN_MODE_DIRECT, this sign mode does not require signers signing over other signers' `signer_info`. It also allows for adding Tips in transactions. |
 | SIGN_MODE_LEGACY_AMINO_JSON | 127 | SIGN_MODE_LEGACY_AMINO_JSON is a backwards compatibility mode which uses Amino JSON and will be removed in the future. |
 
 
@@ -8653,6 +8656,7 @@ transaction.
 | ----- | ---- | ----- | ----------- |
 | `signer_infos` | [SignerInfo](#cosmos.tx.v1beta1.SignerInfo) | repeated | signer_infos defines the signing modes for the required signers. The number and order of elements must match the required signers from TxBody's messages. The first element is the primary signer and the one which pays the fee. |
 | `fee` | [Fee](#cosmos.tx.v1beta1.Fee) |  | Fee is the fee and gas limit for the transaction. The first signer is the primary signer and the one which pays the fee. The fee can be calculated based on the cost of evaluating the body and doing signature verification of the signers. This can be estimated via simulation. |
+| `tip` | [Tip](#cosmos.tx.v1beta1.Tip) |  | Tip is the optional tip used for meta-transactions. |
 
 
 
@@ -8746,6 +8750,27 @@ SignDoc is the type used for generating sign bytes for SIGN_MODE_DIRECT.
 
 
 
+<a name="cosmos.tx.v1beta1.SignDocDirectAux"></a>
+
+### SignDocDirectAux
+SignDocDirectAux is the type used for generating sign bytes for
+SIGN_MODE_DIRECT_AUX.
+
+
+| Field | Type | Label | Description |
+| ----- | ---- | ----- | ----------- |
+| `body_bytes` | [bytes](#bytes) |  | body_bytes is protobuf serialization of a TxBody that matches the representation in TxRaw. |
+| `public_key` | [google.protobuf.Any](#google.protobuf.Any) |  | public_key is the public key of the signing account. |
+| `chain_id` | [string](#string) |  | chain_id is the identifier of the chain this transaction targets. It prevents signed transactions from being used on another chain by an attacker. |
+| `account_number` | [uint64](#uint64) |  | account_number is the account number of the account in state. |
+| `sequence` | [uint64](#uint64) |  | sequence is the sequence number of the signing account. |
+| `tip` | [Tip](#cosmos.tx.v1beta1.Tip) |  | Tip is the optional tip used for meta-transactions. It should be left empty if the signer is not the tipper for this transaction. |
+
+
+
+
+
+
 <a name="cosmos.tx.v1beta1.SignDocJSON"></a>
 
 ### SignDocJSON
@@ -8786,6 +8811,22 @@ signer.
 
 
 
+<a name="cosmos.tx.v1beta1.Tip"></a>
+
+### Tip
+Tip is the tip used for meta-transactions.
+
+
+| Field | Type | Label | Description |
+| ----- | ---- | ----- | ----------- |
+| `amount` | [cosmos.base.v1beta1.Coin](#cosmos.base.v1beta1.Coin) | repeated | amount is the amount of the tip |
+| `tipper` | [string](#string) |  | tipper is the address of the account paying for the tip |
+
+
+
+
+
+
 <a name="cosmos.tx.v1beta1.Tx"></a>
 
 ### Tx

proto/cosmos/tx/signing/v1beta1/signing.proto

@@ -23,9 +23,15 @@ enum SignMode {
 
   // SIGN_MODE_DIRECT_JSON specifies a signing mode which uses SignDocJSON. It
   // is verified using a canonical JSON representation of the bytes used in
-  // SIGN_MODE_DIRECT.
+  // SIGN_MODE_DIRECT. It is currently not supported.
   SIGN_MODE_DIRECT_JSON = 3;
 
+  // SIGN_MODE_DIRECT_AUX specifies a signing mode which uses
+  // SignDocDirectAux. As opposed to SIGN_MODE_DIRECT, this sign mode does not
+  // require signers signing over other signers' `signer_info`. It also allows
+  // for adding Tips in transactions.
+  SIGN_MODE_DIRECT_AUX = 4;
+
   // SIGN_MODE_LEGACY_AMINO_JSON is a backwards compatibility mode which uses
   // Amino JSON and will be removed in the future.
   SIGN_MODE_LEGACY_AMINO_JSON = 127;

proto/cosmos/tx/v1beta1/tx.proto

@@ -96,6 +96,32 @@ message SignDocJSON {
   bytes sign_doc_sha256_hash = 5;
 }
 
+// SignDocDirectAux is the type used for generating sign bytes for
+// SIGN_MODE_DIRECT_AUX.
+message SignDocDirectAux {
+  // body_bytes is protobuf serialization of a TxBody that matches the
+  // representation in TxRaw.
+  bytes body_bytes = 1;
+
+  // public_key is the public key of the signing account.
+  google.protobuf.Any public_key = 2;
+
+  // chain_id is the identifier of the chain this transaction targets.
+  // It prevents signed transactions from being used on another chain by an
+  // attacker.
+  string chain_id = 3;
+
+  // account_number is the account number of the account in state.
+  uint64 account_number = 4;
+
+  // sequence is the sequence number of the signing account.
+  uint64 sequence = 5;
+
+  // Tip is the optional tip used for meta-transactions. It should be left
+  // empty if the signer is not the tipper for this transaction.
+  Tip tip = 6;
+}
+
 // TxBody is the body of a transaction that all signers sign over.
 message TxBody {
   // messages is a list of messages to be executed. The required signers of
@@ -141,6 +167,9 @@ message AuthInfo {
   // based on the cost of evaluating the body and doing signature verification
   // of the signers. This can be estimated via simulation.
   Fee fee = 2;
+
+  // Tip is the optional tip used for meta-transactions.
+  Tip tip = 3;
 }
 
 // SignerInfo describes the public key and signing mode of a single top-level
@@ -214,3 +243,11 @@ message Fee {
   // not support fee grants, this will fail
   string granter = 4;
 }
+
+// Tip is the tip used for meta-transactions.
+message Tip {
+  // amount is the amount of the tip
+  repeated cosmos.base.v1beta1.Coin amount = 1;
+  // tipper is the address of the account paying for the tip
+  string tipper = 2;
+}