diff --git a/proto/cusf/common/v1/common.proto b/proto/cusf/common/v1/common.proto
index bbc6681..104bf59 100644
--- a/proto/cusf/common/v1/common.proto
+++ b/proto/cusf/common/v1/common.proto
@@ -13,4 +13,17 @@ message ConsensusHex {
 /// Reverse-encoded hex
 message ReverseHex {
   google.protobuf.StringValue hex = 1;
-}
\ No newline at end of file
+}
+
+message SidechainDeclarationV0 {
+  google.protobuf.StringValue title = 1;
+  google.protobuf.StringValue description = 2;
+  ConsensusHex hash_id_1 = 3;
+  ConsensusHex hash_id_2 = 4;
+}
+
+message SidechainDeclaration {
+  oneof version {
+    SidechainDeclarationV0 v0 = 1;
+  }
+}
diff --git a/proto/cusf/mainchain/v1/common.proto b/proto/cusf/mainchain/v1/common.proto
new file mode 100644
index 0000000..3a3a15e
--- /dev/null
+++ b/proto/cusf/mainchain/v1/common.proto
@@ -0,0 +1,25 @@
+/* Common message types */
+
+syntax = "proto3";
+package cusf.mainchain.v1;
+
+import "google/protobuf/wrappers.proto";
+
+import "cusf/common/v1/common.proto";
+
+message OutPoint {
+  cusf.common.v1.ReverseHex txid = 1;
+  google.protobuf.UInt32Value vout = 2;
+}
+
+message SidechainDeclaration {
+  message V0 {
+    google.protobuf.StringValue title = 1;
+    google.protobuf.StringValue description = 2;
+    cusf.common.v1.ConsensusHex hash_id_1 = 3;
+    cusf.common.v1.ConsensusHex hash_id_2 = 4;
+  }
+  oneof sidechain_declaration {
+    V0 v0 = 1;
+  }
+}
diff --git a/proto/cusf/mainchain/v1/validator.proto b/proto/cusf/mainchain/v1/validator.proto
index 9b9e927..28532e2 100644
--- a/proto/cusf/mainchain/v1/validator.proto
+++ b/proto/cusf/mainchain/v1/validator.proto
@@ -6,6 +6,7 @@ package cusf.mainchain.v1;
 import "google/protobuf/wrappers.proto";
 
 import "cusf/common/v1/common.proto";
+import "cusf/mainchain/v1/common.proto";
 
 message BlockHeaderInfo {
   cusf.common.v1.ReverseHex block_hash = 1;
@@ -24,11 +25,6 @@ enum Network {
   NETWORK_TESTNET = 5;
 }
 
-message OutPoint {
-  cusf.common.v1.ConsensusHex txid = 1;
-  uint32 vout = 2;
-}
-
 message Output {
   cusf.common.v1.ConsensusHex address = 2;
   uint64 value_sats = 3;
@@ -59,19 +55,6 @@ message BlockInfo {
   optional cusf.common.v1.ConsensusHex bmm_commitment = 3;
 }
 
-message SidechainDeclarationV0 {
-  google.protobuf.StringValue title = 1;
-  google.protobuf.StringValue description = 2;
-  cusf.common.v1.ConsensusHex hash_id_1 = 3;
-  cusf.common.v1.ConsensusHex hash_id_2 = 4;
-}
-
-message SidechainDeclaration {
-  oneof version {
-    SidechainDeclarationV0 v0 = 1;
-  }
-}
-
 service ValidatorService {
   rpc GetBlockHeaderInfo(GetBlockHeaderInfoRequest)
     returns (GetBlockHeaderInfoResponse);
@@ -147,7 +130,7 @@ message GetCoinbasePSBTRequest {
   }
   message ProposeBundle {
     google.protobuf.UInt32Value sidechain_number = 1;
-    cusf.common.v1.ConsensusHex bundle_txid = 2;
+    cusf.common.v1.ReverseHex bundle_txid = 2;
   }
   message AckBundles {
     message RepeatPrevious {
@@ -178,7 +161,7 @@ message GetCtipRequest {
 }
 message GetCtipResponse {
   message Ctip {
-    cusf.common.v1.ConsensusHex txid = 1;
+    cusf.common.v1.ReverseHex txid = 1;
     uint32 vout = 2;
     uint64 value = 3;
     uint64 sequence_number = 4;
@@ -190,24 +173,19 @@ message GetSidechainProposalsRequest {
 }
 message GetSidechainProposalsResponse {
   message SidechainProposal {
-    uint32 sidechain_number = 1;
-
-    // protolint:disable MAX_LINE_LENGTH
-
-    // Raw sidechain proposal data (M1 message of BIP300)
-    // https://github.com/bitcoin/bips/blob/master/bip-0300.mediawiki#m1----propose-sidechain
-    google.protobuf.BytesValue data = 2;
+    google.protobuf.UInt32Value sidechain_number = 1;
 
-    // protolint:enable MAX_LINE_LENGTH
+    // Raw sidechain proposal description
+    cusf.common.v1.ConsensusHex description = 2;
 
     // Sidechain data, as declared in the M1 proposal.
     // Might be nil, if the proposal uses an unknown version.
     optional SidechainDeclaration declaration = 7;
 
-    cusf.common.v1.ConsensusHex data_hash = 3;
-    uint32 vote_count = 4;
-    uint32 proposal_height = 5;
-    uint32 proposal_age = 6;
+    cusf.common.v1.ReverseHex description_sha256d_hash = 3;
+    google.protobuf.UInt32Value vote_count = 4;
+    google.protobuf.UInt32Value proposal_height = 5;
+    google.protobuf.UInt32Value proposal_age = 6;
   }
   repeated SidechainProposal sidechain_proposals = 1;
 }
@@ -216,11 +194,11 @@ message GetSidechainsRequest {
 }
 message GetSidechainsResponse {
   message SidechainInfo {
-    uint32 sidechain_number = 1;
-    google.protobuf.BytesValue data = 2;
-    uint32 vote_count = 3;
-    uint32 proposal_height = 4;
-    uint32 activation_height = 5;
+    google.protobuf.UInt32Value sidechain_number = 1;
+    cusf.common.v1.ConsensusHex description = 2;
+    google.protobuf.UInt32Value vote_count = 3;
+    google.protobuf.UInt32Value proposal_height = 4;
+    google.protobuf.UInt32Value activation_height = 5;
   }
   repeated SidechainInfo sidechains = 1;
 }
diff --git a/proto/cusf/mainchain/v1/wallet.proto b/proto/cusf/mainchain/v1/wallet.proto
index bbbab31..f4b2315 100644
--- a/proto/cusf/mainchain/v1/wallet.proto
+++ b/proto/cusf/mainchain/v1/wallet.proto
@@ -6,6 +6,7 @@ package cusf.mainchain.v1;
 import "google/protobuf/wrappers.proto";
 
 import "cusf/common/v1/common.proto";
+import "cusf/mainchain/v1/common.proto";
 
 service WalletService {
   rpc BroadcastWithdrawalBundle(BroadcastWithdrawalBundleRequest)
@@ -16,6 +17,14 @@ service WalletService {
     returns (CreateDepositTransactionResponse);
   rpc CreateNewAddress(CreateNewAddressRequest)
     returns (CreateNewAddressResponse);
+  // Create a new sidechain proposal (M1 in BIP300) and persist to the local
+  // database for further processing.
+  // Sidechain proposals must be included in the coinbase transaction of a
+  // newly mined block, so this proposal is not active until the wallet has
+  // been able to generate a new block.
+  // Returns a stream of (non-)confirmation events for the sidechain proposal.
+  rpc CreateSidechainProposal(CreateSidechainProposalRequest)
+    returns (stream CreateSidechainProposalResponse);
   // Regtest only
   rpc GenerateBlocks(GenerateBlocksRequest)
     returns (GenerateBlocksResponse);
@@ -36,7 +45,7 @@ message CreateBmmCriticalDataTransactionRequest {
   cusf.common.v1.ReverseHex prev_bytes = 5;
 }
 message CreateBmmCriticalDataTransactionResponse {
-  cusf.common.v1.ConsensusHex txid = 1;
+  cusf.common.v1.ReverseHex txid = 1;
 }
 
 message CreateDepositTransactionRequest {
@@ -46,7 +55,7 @@ message CreateDepositTransactionRequest {
   uint64 fee_sats = 4;
 }
 message CreateDepositTransactionResponse {
-  cusf.common.v1.ConsensusHex txid = 1;
+  cusf.common.v1.ReverseHex txid = 1;
 }
 
 message CreateNewAddressRequest {
@@ -56,6 +65,30 @@ message CreateNewAddressResponse {
   string address = 1;
 }
 
+message CreateSidechainProposalRequest {
+  google.protobuf.UInt32Value sidechain_id = 1;
+  SidechainDeclaration declaration = 2;
+}
+
+message CreateSidechainProposalResponse {
+  message Confirmed {
+    cusf.common.v1.ReverseHex block_hash = 1;
+    google.protobuf.UInt32Value confirmations = 2;
+    google.protobuf.UInt32Value height = 3;
+    OutPoint outpoint = 4;
+    cusf.common.v1.ReverseHex prev_block_hash = 5;
+  }
+  message NotConfirmed {
+    cusf.common.v1.ReverseHex block_hash = 1;
+    google.protobuf.UInt32Value height = 2;
+    cusf.common.v1.ReverseHex prev_block_hash = 3;
+  }
+  oneof event {
+    Confirmed confirmed = 1;
+    NotConfirmed not_confirmed = 2;
+  }
+}
+
 message GenerateBlocksRequest {
   google.protobuf.UInt32Value blocks = 1;
 }