lbcd/release

btcd's Reproducible Build System

This package contains the build script that the btcd project uses in order to build binaries for each new release. As of go1.13, with some new build flags, binaries are now reproducible, allowing developers to build the binary on distinct machines, and end up with a byte-for-byte identical binary. However, this wasn't fully solved in go1.13, as the build system still includes the directory the binary is built into the binary itself. As a result, our scripts utilize a work around needed until go1.13.2.

Building a New Release

macOS/Linux/Windows (WSL)

No prior set up is needed on Linux or macOS is required in order to build the release binaries. However, on Windows, the only way to build the release binaries at the moment is by using the Windows Subsystem Linux. One can build the release binaries following these steps:

1. git clone https://github.com/btcsuite/btcd.git
2. cd btcd
3. ./release/release.sh <TAG> # <TAG> is the name of the next release/tag

This will then create a directory of the form btcd-<TAG> containing archives of the release binaries for each supported operating system and architecture, and a manifest file containing the hash of each archive.

Verifying a Release

With go1.13, it's now possible for third parties to verify release binaries. Before this version of go, one had to trust the release manager(s) to build the proper binary. With this new system, third parties can now independently run the release process, and verify that all the hashes of the release binaries match exactly that of the release binaries produced by said third parties.

To verify a release, one must obtain the following tools (many of these come installed by default in most Unix systems): gpg/gpg2, shashum, and tar/unzip.

Once done, verifiers can proceed with the following steps:

1. Acquire the archive containing the release binaries for one's specific operating system and architecture, and the manifest file along with its signature.
2. Verify the signature of the manifest file with gpg --verify manifest-<TAG>.txt.sig. This will require obtaining the PGP keys which signed the manifest file, which are included in the release notes.
3. Recompute the SHA256 hash of the archive with shasum -a 256 <filename>, locate the corresponding one in the manifest file, and ensure they match exactly.

At this point, verifiers can use the release binaries acquired if they trust the integrity of the release manager(s). Otherwise, one can proceed with the guide to verify the release binaries were built properly by obtaining shasum and go (matching the same version used in the release):

4. Extract the release binaries contained within the archive, compute their hashes as done above, and note them down.
5. Ensure go is installed, matching the same version as noted in the release notes.
6. Obtain a copy of btcd's source code with git clone https://github.com/btcsuite/btcd and checkout the source code of the release with git checkout <TAG>.
7. Proceed to verify the tag with git verify-tag <TAG> and compile the binaries from source for the intended operating system and architecture with BTCDBUILDSYS=OS-ARCH ./release/release.sh <TAG>.
8. Extract the archive found in the btcd-<TAG> directory created by the release script and recompute the SHA256 hash of the release binaries (btcd and btcctl) with shasum -a 256 <filename>. These should match exactly as the ones noted above.