feat: add miden-objects with canonical Protobuf representations

CHANGELOG.md

@@ -8,6 +8,7 @@
 - [BREAKING] AggLayer bridge and faucet accounts now map note repricing to an initial `FEE_MNGR` role instead of the built-in `ADMIN` role ([#3571](https://github.com/0xMiden/protocol/issues/3571)).
 - [BREAKING] AggLayer bridge accounts now map emergency pause to an initial `PAUSER` role, while unpause remains restricted to `ADMIN` ([#3572](https://github.com/0xMiden/protocol/issues/3572)).
 - Added the block kernel skeleton, establishing its public input/output contract and the `BlockExecutor` that runs it ([#3703](https://github.com/0xMiden/protocol/pull/3703)).
+- Added the `miden-objects` crate with canonical, `no_std`-compatible Protobuf representations and validated conversions for protocol objects exchanged between clients and nodes ([#3707](https://github.com/0xMiden/protocol/pull/3707)).
 
 ### Changes
 

Cargo.toml

@@ -4,6 +4,7 @@ members = [
   "bin/bench-transaction",
   "crates/miden-agglayer",
   "crates/miden-block-prover",
+  "crates/miden-objects",
   "crates/miden-protocol",
   "crates/miden-protocol-build-utils",
   "crates/miden-standards",
@@ -69,6 +70,9 @@ bon             = { default-features = false, version = "3" }
 criterion       = { default-features = false, version = "0.5" }
 fs-err          = { default-features = false, version = "3" }
 primitive-types = { default-features = false, version = "0.14" }
+prost           = { default-features = false, version = "0.14" }
+prost-build     = { default-features = false, version = "0.14" }
+protox          = { default-features = false, version = "0.9" }
 rand            = { default-features = false, version = "0.10" }
 rand_chacha     = { default-features = false, version = "0.10" }
 regex           = { version = "1.11" }

README.md

@@ -50,6 +50,7 @@ We expect to keep making changes (including breaking changes) to all components.
 | [miden-agglayer](crates/miden-agglayer) | AggLayer components for the Miden protocol. |
 | [miden-block-prover](crates/miden-block-prover) | Block execution and proving tools. |
 | [miden-protocol](crates/miden-protocol) | Core protocol components, including the protocol kernels. |
+| [miden-objects](crates/miden-objects) | Canonical Protobuf representations for protocol objects exchanged by clients and nodes. |
 | [miden-protocol-build-utils](crates/miden-protocol-build-utils) | Build-time MASM helpers. |
 | [miden-standards](crates/miden-standards) | Standardized smart contracts. |
 | [miden-testing](crates/miden-testing) | Testing tools for Miden transactions, batches, and blocks. |

crates/miden-objects/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+authors.workspace      = true
+categories             = ["encoding", "no-std"]
+description            = "Canonical Protobuf representations for Miden protocol objects"
+edition.workspace      = true
+homepage.workspace     = true
+keywords               = ["miden", "protobuf", "protocol", "serialization"]
+license.workspace      = true
+name                   = "miden-objects"
+readme                 = "README.md"
+repository.workspace   = true
+rust-version.workspace = true
+version.workspace      = true
+
+[features]
+default = ["std"]
+std     = ["miden-protocol/std", "prost/std"]
+
+[dependencies]
+miden-protocol = { workspace = true }
+prost          = { features = ["derive"], workspace = true }
+
+[build-dependencies]
+prost       = { features = ["derive"], workspace = true }
+prost-build = { workspace = true }
+protox      = { workspace = true }
+
+[dev-dependencies]
+miden-protocol = { features = ["testing"], workspace = true }

crates/miden-objects/README.md

@@ -0,0 +1,18 @@
+# Miden Objects
+
+Canonical Protobuf representations for values exchanged between Miden clients and nodes.
+
+This crate owns the transport representation and conversions for protocol objects. It does not
+define protocol commitments, replace the protocol's native serialization, or define RPC services.
+Generated messages are exposed under `miden_objects::proto`.
+
+The crate supports `no_std` consumers when default features are disabled.
+
+RPC crates can use `FILE_DESCRIPTOR_SET` as the import descriptor and apply every entry in
+`EXTERN_PATHS` with `prost_build::Config::extern_path`. This makes imported object messages resolve
+to the canonical generated types from this crate instead of generating duplicate Rust types in the
+RPC crate.
+
+## License
+
+This project is [MIT licensed](../../LICENSE).