cristicmf / town-crier

Town Crier: an Authenticated Data Feeds for Smart Contracts

Town Crier: An Authenticated Data Feed For Smart Contracts

Smart contracts systems today lack trustworthy sources of data, as currently deployed oracles provide only weak provenance and confidentiality guarantees. The Town Crier (TC) system leverages trusted hardware (Intel SGX) to provide a strong guarantee that data comes from an existing, trustworthy source. It also provides confidentiality, enabling smart contracts to support confidential queries and manage user credentials.

Please read on for build instructions for the TC enclave. If you want to learn how Town Crier works and how to use TC in smart contract systems, please visit http://town-crier.org.

Build with Docker

git clone https://github.com/bl4ck5un/Town-Crier
cd Town-Crier
./scripts/sgx-enter.sh
cmake ../code
make && make install

To print MRENCLAVE,

root@08119b795b16:/build# /tc/bin/tc -m
# omit logging
E1FBB750A350798ADBECAFEE8A1BFC5B229E3BC007212E92102B55CE30EA0C01

Alternatively, MRENCLAVE can be extracted manually from the sgx_metadata section of the enclave binary.

Launch TC

TC relies on geth to communicate with Ethereum blockchain. By default TC connects to geth via RPC at http://localhost/8200. The RPC entrypoint can be changed in the configuration file. After make install, a sample configuration is installed at /tc/conf/config-sim-test.

root@3405273772d1:/build# cat /tc/conf/config-sim-test 
[RPC]
RPChost = http://localhost:8200

[init]
enclave_path = /tc/enclave/enclave.debug.so

[daemon]
pid_file = tc.pid

[status]
enabled = true
port = 8123

[sealed]
sig_key = blahblah
hybrid_key = blahblah

To launch TC (in the above docker where tc is built):

Status Server

curl -d '{"id": 123, "jsonrpc": "2.0", "method": "attest"}' server.town-crier.org:8123

LICENSE

The permission granted herein is solely for the purpose of compiling the TownCrier source code. See the LICENSE file for details.