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If you wish to build paratime binaries yourself, you can use the environment provided as part of the SDK. This way you can also verify that the binaries match the ones running on the network.

The steps below show how to build the test runtimes provided in the oasis-sdk sources; steps for other paratimes should be similar.

Environment Setup

The build environment is provided as a Docker image containing all the necessary tools. Refer to your system's documentation for pointers on installing software.

The runtime sources need to be mounted into the container so prepare a directory first, such as:

git clone

Running the Image

The images are available in the repository on Docker Hub and are tagged with the same version numbers as releases of the SDK. To pull the image and run a container with it, run the following:

docker run -t -i -v /home/user/oasis-sdk:/src /bin/bash


  • /home/user/oasis-sdk is the absolute path to the directory containing the SDK sources (or other paratimes - you likely do not need to download the SDK separately if you're building other paratimes), and
  • main is a release of the SDK - the documentation of the paratime you're trying to build should mention the version required.

This gives you a root shell in the container. Rust and Cargo are installed in /cargo, Go in /go, and the sources to your paratime are available in /src.



Simply build the paratime in release mode using:

cargo build --release

The resulting binaries will be in /src/target/release/.

Intel SGX

Follow the normal build procedure for your paratime. For the testing runtimes in the SDK, e.g.:

cd /src
cargo build --release --target x86_64-fortanix-unknown-sgx

After this step is complete, the binaries will be in /src/target/x86_64-fortanix-unknown-sgx/release/.

To produce the sgxs format needed on the Oasis network, change directory to where a particular runtime's Cargo.toml file is and run the following command:

cargo elf2sgxs --release

It is necessary to change directories first because the tool does not currently support cargo workspaces.

The resulting binaries will have the .sgxs extension.

Generating Bundles

Oasis Core since version 22.0 distributes bundles in the Oasis Runtime Container format which is basically a zip archive with some metadata attached. This makes it easier for node operators to configure paratimes. To ease creation of such bundles from built binaries and metadata, you can use the orc tool provided by the SDK.


You can install the orc utility by running:

go install

The same bundle can contain both ELF and Intel SGX artifacts. To create a bundle use the following command:

orc init path/to/elf-binary

When including Intel SGX artifacts you may additionally specify:


All bundles, even Intel SGX ones, are required to include an ELF binary of the paratime. This binary is used for client nodes that don't have SGX support.

orc init path/to/elf-binary --sgx-executable path/to/binary.sgxs --sgx-signature path/to/binary.sig

You can omit the signature initially and add it later by using:

orc sgx-set-sig bundle.orc path/to/binary.sig

Multi-step SGX Signing Example

Multi-step signing allows enclave signing keys to be kept offline, preferrably in some HSM. The following example uses openssl and a locally generated key as an example, however, it is suggested that the key be stored in a more secure location than in plaintext on disk.

Generate a key

We will generate a valid key for enclave signing. This must be a 3072-bit RSA key with a public exponent of 3. Do this like so:

openssl genrsa -3 3072 > private.pem

We will also need the public key in a later step so let's also generate this now.

openssl rsa -in private.pem -pubout > public.pem

Generate signing data for your enclave

Generating signing data is done with the orc sgx-gen-sign-data subcommand, like so:

orc sgx-gen-sign-data [options] bundle.orc

See orc sgx-gen-sign-data --help for details on available options.

For purposes of this example, let's assume your bundle is named bundle.orc. You would generate data to sign like so:

orc sgx-gen-sign-data bundle.orc > sigstruct.sha256.bin

The output file sigstruct.sha256.bin contains the sha256 hash of the SIGSTRUCT fields to be signed.

Sign the SIGSTRUCT hash

To sign the SIGSTRUCT you must create a signature using the RSASSA-PKCS1-v1_5 scheme. The following command will do so with openssl. If you're using an HSM, your device may have a different process for generating a signature of this type.

openssl pkeyutl -sign \
-in sigstruct.sha256.bin \
-inkey private.pem \
-out sigstruct.sha256.sig \
-pkeyopt digest:sha256
Attach the singed SIGSTRUCT to the bundle

With the signature in sigstruct.sha256.sig we can now generate a valid SIGSTRUCT and attach it into the bundle.

orc sgx-set-sig bundle.orc sigstruct.sha256.sig public.pem

If there are no errors, bundle.orc will now contain a valid SGX SIGSTRUCT that was signed by private.pem. To verify you can use orc show as follows.

orc show bundle.orc

It should return something like the following, showing the bundle content including the signed SGX SIGSTRUCT (the signature is also verified):

Bundle:         /path/to/bundle.orc
Name: my-paratime
Runtime ID: 000000000000000000000000000000000000000000000000a6d1e3ebf60dff6c
Version: 0.1.1
Executable: runtime.elf
SGXS: runtime.sgx
SGXS MRENCLAVE: a68535bda1574a5e15dfb155c26e39bd404e9991a4d98010581a35d053011340
SGXS signature: runtime.sgx.sig
Build date: 2022-07-14 00:00:00 +0000 UTC
MiscSelect: 00000000
MiscSelect mask: FFFFFFFF
Attributes flags: 0000000000000004
- 64-bit mode
Attributes XFRM: 0000000000000003
MRENCLAVE: a68535bda1574a5e15dfb155c26e39bd404e9991a4d98010581a35d053011340
ISV product ID: 0
runtime.sgx.sig => 3c0daea89dfdb3d0381147dec3e041a596617f686afa9b28436ca17980dafee4
runtime.elf => a96397fc309bc2116802315c0341a2a9f6f21935d79a3f56d71b3e4d6f6d9302
runtime.sgx => b96ff3ae9c73646459b7e8dc1d096838720a7c62707affc1800967cbee99b28b