Key Management System for Tendermint applications, initially targeting Cosmos Validators.
This repository contains tmkms
, a key management service intended to be deployed
in conjunction with Tendermint applications (ideally on separate physical hosts)
which provides the following:
- High-availability access to validator signing keys
- Double-signing prevention even in the event the validator process is compromised
- Hardware security module storage for validator keys which can survive host compromise
Tendermint KMS is currently ALPHA SOFTWARE AND UNAUDITED -- USE AT YOUR OWN RISK.
It supports YubiHSM 2 and Ledger as hardware-backed key storage methods.
The following high severity security issues are still unresolved:
Work is underway to address them both.
For now we recommend the connection between the KMS and validators occur over an isolated network and not depend solely on the Secret Connection protocol for authentication and confidentiality (which is also a good idea in general for defense-in-depth purposes).
Tendermint KMS implements alpha quality double signing detection. Please see #60: Double-signing prevention (MVP for launch) for more information, however note this implementation is limited.
In particular, KMS does NOT prevent double signing if two instances are running as identical copies, an attacker compromises both (as a signing oracle), and uses both instances to double sign.
The longer-term story around double-signing is more complex, as it includes such scenarios as signing while unbonded. For more information on future-plans to provide double-signing defense and high availability in such scenarions, see #115: Dobule signing prevention (post-launch).
tmkms
should build on any supported Rust platform which is also supported
by libusb. Below are some of the available tier 1, 2, and 3 Rust platforms
which are also supported by libusb.
NOTE: tmkms
is presently tested on Linux/x86_64. We don't otherwise guarantee
support for any of the platforms below, but they theoretically meet the necessary
prerequisites for support.
- Linux (recommended)
- FreeBSD
- NetBSD
- OpenBSD
- macOS
x86_64
(recommended)arm
(32-bit ARM)aarch64
(64-bit ARM)mips
(32-bit MIPS)mips64
(64-bit MIPS)powerpc
(32-bit PowerPC)powerpc64
(64-bit PowerPC)sparc64
(64-bit SPARC)
You will need the following prerequisites:
- Rust (stable; 1.35+): https://rustup.rs/
- C compiler: e.g. gcc, clang
- pkg-config
- libusb (1.0+). Install instructions for common platforms:
- Debian/Ubuntu:
apt install libusb-1.0-0-dev
- RedHat/CentOS:
yum install libusb1-devel
- macOS (Homebrew):
brew install libusb
- Debian/Ubuntu:
NOTE (x86_64 only): Configure RUSTFLAGS
environment variable:
export RUSTFLAGS=-Ctarget-feature=+aes,+ssse3
There are two ways to install tmkms
: either compiling the source code after
cloning it from git, or using Rust's cargo install
command.
tmkms
can be compiled directly from the git repository source code using the
following method.
The following example adds --features=yubihsm
to enable YubiHSM 2 support.
$ git clone https://github.com/tendermint/kms.git && cd kms
[...]
$ cargo build --release --features=yubihsm
Alternatively, substitute --features=ledgertm
to enable Ledger support.
If successful, this will produce a tmkms
executable located at
./target/release/tmkms
With Rust (1.35+) installed, you can install tmkms with the following:
cargo install tmkms --features=yubihsm
Or to install a specific version (recommended):
cargo install tmkms --features=yubihsm --version=0.4.0
Alternatively, substitute --features=ledgertm
to enable Ledger support.
After compiling, start tmkms
with the following:
$ tmkms start
This will read the configuration from the tmkms.toml
file in the current
working directory.
To explicitly specify the path to the configuration, use the -c
flag:
$ tmkms start -c /path/to/tmkms.toml
The following are instructions for setting up a development environment. They assume you've already followed steps 1 & 2 from the Installation section above.
- Install rustfmt:
rustup component add rustfmt
- Install clippy:
rustup component add clippy
Alternatively, you can build a Docker image from the Dockerfile in the top level of the repository, which is what is used to run tests in CI.
Before opening a pull request, please run the checks below:
Run the test suite with:
cargo test --all-features
Make sure your code is well-formatted by running:
cargo fmt
Lint your code (i.e. check it for common issues) with:
cargo clippy
Copyright © 2018-2019 Tendermint
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
https://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.