craggy

Craggy is a Roughtime secure time synchronization client implementation in C. It draws both code and inspiration from the Google C++ client implementation.

Dependencies

Craggy requires two cryptographic operations to work, ED 25519 signature validation and SHA512. Current build can be configured to use either OpenSSL or the ED 25519 implementation from https://github.com/orlp/ed25519 (which also provides SHA512).

To configure the crypto provider, use '-DCRAGGY_WITH_OPENSSL_BINDINGS=ON' or '-DCRAGGY_WITH_ORLP_ED25519_BINDINGS=ON' respectively.

When using the OpenSSL, Craggy will link to the platform provided OpenSSL libraries, while when using the ORLP/ED25519 implementation, it will download and compile the sources for that as part of the build.

Getting started

The following will build craggy static library with ORLP/ED25519 bindings, the craggy-cli command line client (located in the build/cli folder) and the craggy-test runner (located in the test folder)

bash$ git clone https://github.com/nahojkap/craggy.git
...
bash$ cd craggy
bash$ cmake -E make_directory ./build
bash$ cmake -S . -B ./build/ -DCRAGGY_WITH_ORLP_ED25519_BINDINGS=ON
...
bash$ cd build
bash$ make
...
bash$ make test
..
bash$

API

The API of Craggy is defined in the CraggyClient.h header file.

A UDP transport implementation is available (compiled in by default) and is defined in CraggyTransport.h

Generating Nonces

/** Generates a new nonce value, placing it in the nonce specified.
 * 
 * @param result Result of the nonce creation
 * @param nonce Nonce to place the generated value in
 * @return True if successful, otherwise false and {@link result} will indicate the error
 */
bool craggy_generateNonce(CraggyResult *result, craggy_rough_time_nonce_t nonce);

Creating Requests

/** Creates a new Roughtime request message containing the specified nonce.
 *
 * @param nonce The nonce to include in the request
 * @param requestBuf Buffer for the request
 * @param requestBufLen Buffer length
 * @return True if the request creation was successful, otherwise false
 */
bool craggy_createRequest(craggy_rough_time_nonce_t nonce, craggy_rough_time_request_t requestBuf);

Processing Responses

/** Processes a response from the server, verifying the necessary signatures and extracting the time and radius if successful.
 *
 * @param nonce The nonce originally used for creating the request
 * @param rootPublicKey Root public key of the server in question
 * @param responseBuf Response to be processed
 * @param responseBufLen Size of the response to be processed
 * @param result Result of response processing
 * @param time Time reported by the server
 * @param radius Radius reported by the server
 * @return True if the request creation was successful, otherwise false and {@link result} will signal the error
 */
bool craggy_processResponse(craggy_rough_time_nonce_t nonce, craggy_rough_time_public_key_t rootPublicKey, craggy_rough_time_response_t *responseBuf, size_t responseBufLen, CraggyResult *result, craggy_rough_time_t *time, craggy_rough_time_radius_t *radius);

Sending/Receiving a Request/Response

/** Send a Roughtime request to the server and return the response received.
 *
 * @param address The host/port to send the paylaod to.  In the form of <hostname> or <hostname:port>.  If port is omitted, the transports default value will be used.
 * @param requestBuf Buffer containing the request to send.
 * @param result Result of transport operation
 * @param responseBuf Buffer used for response
 * @param responseBufLen Size of the response buffer.  If a response is successfully received, the corresponding size of the response is signalled here too.
 * @return True if the request is successful, otherwise false (and outResult will indicate the error)
 */
bool craggy_makeRequest(const char *address, const craggy_rough_time_request_t requestBuf, CraggyResult *result, craggy_rough_time_response_t *responseBuf, size_t *responseBufLen);

Command line

The command line for the craggy-cli requires the below parameters. If nonce is not specified on the command line, a random one will be generated.

usage: craggy-cli -h <hostname:port> -k <base64 encoded public key of server> (-n <64-bit base64 encoded nonce>)

Example

bash$ cli/craggy -h roughtime.cloudflare.com:2002 -k gD63hSj3ScS+wuOeGrubXlq35N1c5Lby/S+T7MNTjxo=
Received reply in 24291μs.
Current time is 1602858064681145μs from the epoch, ±1000000μs 
System clock differs from that estimate by 110μs.