Add support for protobuf TxGenerator and SIGN_MODE_DIRECT (#6385)

* Add TxWrapper, encoder, decoder and DirectModeHandler

* fix pkg name

* Update API and leave test TODO's

* Update TxWrapper API

* tests for tx wrapper (#6410)

* WIP: added test for direct mode handler

* updated code

* Add msg

* Update TxWrapper API

* Fix pubkey declaration

* Add pubkey for tests

* Fix SetFee

* Remove logs

* Avoid global var declaration for tests

* Add test for GetPubKeys

* Fix direct signing tests

* Add more test cases for GetSignBytes

* Revert SetFee API

* Remove logs

* Refactor tests

Co-authored-by: anilCSE <anil@vitwit.com>
Co-authored-by: sahith-narahari <sahithnarahari@gmail.com>

* Refactoring

* Refactoring

* Integrate SignatureV2 API

* Fix wrapper tests

* Fix tests

* Linting and API tweaks

* Update API

* WIP on updating API

* Fix tests

* Update to new SigVerifiableTx

* Rename

* Update docs to reflect ADR 020

* proto-gen

* proto docs

* cleanup

* cleanup

* cleanup

* cleanup

* cleanup

* cleanup

* cleanup

* Add tests

* Refactor and improving test coverage

* WIP on test coverage

* WIP on test coverage

* proto-gen

* Fix CompactBitArray.Size() bug

* Rename

* Remove Builder interface

* Address review comments

* Update x/auth/tx/sigs.go

Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

* Update x/auth/tx/encoder.go

Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

* Update x/auth/tx/encoder.go

Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

* Address review feedback

* Fix build issues

* Resolve conflicts

* Fix ValidateBasic test coverage

* Add test for malicious multisig

Co-authored-by: atheeshp <59333759+atheeshp@users.noreply.github.com>
Co-authored-by: anilCSE <anil@vitwit.com>
Co-authored-by: sahith-narahari <sahithnarahari@gmail.com>
Co-authored-by: Alexander Bezobchuk <alexanderbez@users.noreply.github.com>
Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

proto/cosmos/crypto/crypto.proto

@@ -42,7 +42,6 @@ message MultiSignature {
 // space after proto encoding.
 // This is not thread safe, and is not intended for concurrent usage.
 message CompactBitArray {
-  option (gogoproto.sizer)            = false;
   option (gogoproto.goproto_stringer) = false;
 
   uint32 extra_bits_stored = 1;

proto/cosmos/tx/tx.proto

@@ -18,17 +18,34 @@ message Tx {
   // signers, signer modes and fee
   AuthInfo auth_info = 2;
 
-  // signatures are the raw binary signatures of signers specified by body and auth_info
+  // signatures is a list of signatures that matches the length and order of AuthInfo's signer_infos to
+  // allow connecting signature meta information like public key and signing mode by position.
   repeated bytes signatures = 3;
 }
 
-// SignDoc is the standard type used for signing transaction in SIGN_MODE_DIRECT
-message SignDoc {
-  // body is the TxBody from Tx
-  TxBody body = 1;
+// TxRaw is a variant of Tx that pins the signer's exact binary representation of body and
+// auth_info. This is used for signing, broadcasting and verification. The binary
+// `serialize(tx: TxRaw)` is stored in Tendermint and the hash `sha256(serialize(tx: TxRaw))`
+// becomes the "txhash", commonly used as the transaction ID.
+message TxRaw {
+  // body_bytes is a protobuf serialization of a TxBody that matches the representation in SignDoc.
+  bytes body_bytes = 1;
 
-  // auth_info is the AuthInfo from Tx
-  AuthInfo auth_info = 2;
+  // auth_info_bytes is a protobuf serialization of an AuthInfo that matches the representation in SignDoc.
+  bytes auth_info_bytes = 2;
+
+  // signatures is a list of signatures that matches the length and order of AuthInfo's signer_infos to
+  // allow connecting signature meta information like public key and signing mode by position.
+  repeated bytes signatures = 3;
+}
+
+// SignDoc is the type used for generating sign bytes for SIGN_MODE_DIRECT
+message SignDoc {
+  // body_bytes is protobuf serialization of a TxBody that matches the representation in TxRaw.
+  bytes body_bytes = 1;
+
+  // auth_info_bytes is a protobuf serialization of an AuthInfo that matches the representation in TxRaw.
+  bytes auth_info_bytes = 2;
 
   // chain_id is the unique identifier of the chain this transaction targets.
   // It prevents signed transactions from being used on another chain by an
@@ -45,7 +62,12 @@ message SignDoc {
 
 // TxBody is the body of a transaction that all signers sign over
 message TxBody {
-  // messages are the processable content of the transaction
+  // messages is a list of messages to be executed. The required signers of those messages define
+  // the number and order of elements in AuthInfo's signer_infos and Tx's signatures.
+  // Each required signer address is added to the list only the first time it occurs.
+  //
+  // By convention, the first required signer (usually from the first message) is referred
+  // to as the primary signer and pays the fee for the whole transaction.
   repeated google.protobuf.Any messages = 1;
 
   // memo is any arbitrary memo to be added to the transaction
@@ -68,21 +90,24 @@ message TxBody {
 
 // AuthInfo describes the fee and signer modes that are used to sign a transaction
 message AuthInfo {
-  // signer_infos is the list of signer infos which corresponds with
-  // Tx.signatures and expected signers derived from TxBody.messages. All signers
-  // are expected to occur in the same order in each of these locations
+  // 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.
   repeated SignerInfo signer_infos = 1;
 
   // Fee is the fee and gas limit for the transaction. The first signer is the
-  // primary signer and the one which pays the fee
+  // 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.
   Fee fee = 2;
 }
 
 // SignerInfo describes the public key and signing mode of a single top-level signer
 message SignerInfo {
   // public_key is the public key of the signer. It is optional for accounts
-  // that already exist in state
-  google.protobuf.Any public_key = 1;
+  // that already exist in state. If unset, the verifier can use the required \
+  // signer address for this position and lookup the public key.
+  cosmos.crypto.PublicKey public_key = 1;
 
   // mode_info describes the signing mode of the signer and is a nested
   // structure to support nested multisig pubkey's