Roughtime

Roughenough is an implementation of the Roughtime (RFC 10049) secure time synchronization protocol. Roughenough provides both server and client components for cryptographically verifiable time synchronization.

• Full implementation of the Roughtime RFC 10049 specification
• Command-line client with multiple output formats and server validation
• Performance oriented batching UDP server
• Clients can (optionally) report malfeasance to a remote server for analysis
• Multiple backends for secure key and identity protection (KMS, Secret Manager, Linux KRS, SSH agent, PKCS#11)

• MSRV 1.94.1 (set by the AWS SDK crates), Rust 2024 edition
• Linux, MacOS, or other Unix-like operating system
• Optional: cloud provider credentials for backend key storage

Build all components:

cargo build --release

Build the server and client with every optional feature a release ships:

cargo build --release -p roughenough-server --features release
cargo build --release -p roughenough-client --features reporting

The server requires a long-term identity seed file to start. Pass its path with --seed-file (or the ROUGHENOUGH_SEED_FILE environment variable). For testing you can use --insecure-zero-seed to run with an all-zero seed.

On Unix-like systems the seed file needs to be a regular file (no symlinks) with 0400 or 0600 file permissions.

The seed file holds text in one of these forms:

• a hex or base64 encoded 32-byte seed, optionally prefixed with seed://
• an AWS or GCP KMS envelope (aws-kms:// or gcp-kms://)
• an AWS or GCP Secret Manager reference (aws-secret:// or gcp-secret://)

The roughenough_keys tool creates the protected forms: generate creates a new random seed and protects it, protect protects the seed in an existing seed file, and recover prints the plain seed that a seed file refers to. Build the tool and the server with the longterm-aws or longterm-gcp feature; see doc/PROTECTION.md.

# Generate a new mode-0600 plain seed file
(umask 077 && openssl rand -hex 32 > seed.txt)

# Encrypt it with AWS KMS; the output is a seed file the server loads
roughenough_keys protect -i seed.txt --resource aws-kms://arn:aws:kms:... -o roughenough.seed

# Or generate a new seed and store it in GCP Secret Manager
roughenough_keys generate --resource gcp-secret://projects/P/secrets/S -o roughenough.seed

# Print the plain seed that a seed file refers to
roughenough_keys recover -i roughenough.seed

# Debug build, testing-only zero seed
cargo run --bin roughenough_server -- --insecure-zero-seed

# Generate a new mode-0600 plain seed file
(umask 077 && openssl rand -hex 32 > roughenough.seed)

# Release build with optimizations and a real seed file
cargo run --release --bin roughenough_server -- --seed-file roughenough.seed

# Run the server binary directly (a read-only file is sufficient)
target/release/roughenough_server --seed-file /run/secrets/roughenough.seed

The server will start listening for UDP requests on the default port (5319, assigned to Roughtime by IANA).

Basic usage:

# Query a Roughtime server
cargo run --bin roughenough_client -- roughtime.int08h.com 5319

# Verify server public key
cargo run --bin roughenough_client -- roughtime.int08h.com 5319 -k <base64-or-hex-key>

# Multiple requests
cargo run --bin roughenough_client -- roughtime.int08h.com 5319 -n 10

# Verbose output
cargo run --bin roughenough_client -- roughtime.int08h.com 5319 -v

# Different time formats
cargo run --bin roughenough_client -- roughtime.int08h.com 5319 --epoch  # Unix timestamp
cargo run --bin roughenough_client -- roughtime.int08h.com 5319 --zulu   # ISO 8601 UTC

Offer draft version 0x8000000c as well as version 1 (see Protocol Versions):

cargo run --bin roughenough_client -- roughtime.example.com 5319 -P both

Query multiple servers from an RFC compliant JSON list:

cargo run --bin roughenough_client -- -l servers.json

With -s, list mode sets the system clock from the last measurement only when no causality violation is found; otherwise it exits with status 1.

The server answers only Roughtime version 1 (RFC 10049) and ignores requests that do not offer it. Version 1 signatures use the RFC 10049 context strings, "Roughtime v1 response signature" and "Roughtime v1 delegation signature".

The client offers version 1 by default. -P both offers version 1 and draft version 0x8000000c, and -P 19 offers only the draft version. Draft responses are verified with the draft context strings ("RoughTime v1 ...").

The server forwards the keys backends as online-pkcs11, online-ssh-agent, longterm-aws, and longterm-gcp; release enables all of them.

• reporting - Enables clients to report malfeasance to a remote server

  cargo build -p roughenough-client --features reporting
  cargo run -p roughenough-client --features reporting --bin roughenough_client -- -l servers.json --report

• test-utils - Test-only: exposes shared fixtures (roughenough_client::test_utils) for other crates' tests; pulls in roughenough-server. Never enable it in builds you ship

See doc/PROTECTION.md for detailed information on seed protection strategies.

• online-linux-krs (default): Store seed in Linux Kernel Keyring for runtime protection
• online-ssh-agent Use SSH agent for seed storage and signing operations
• online-pkcs11 PKCS#11 hardware security module integration (Yubikey, HSM, etc)

• longterm-aws AWS KMS envelope encryption and AWS Secrets Manager
• longterm-gcp GCP Cloud KMS envelope encryption and GCP Secret Manager

Contributions are welcome! See CONTRIBUTING.md for guidelines, the project layout, and development commands.

Thank you to all past and present contributors:

• Stuart Stock (stuart {at} int08h.com)
• Aaron Hill (aa1ronham {at} gmail.com)
• Peter Todd (pete {at} petertodd.org)
• Muncan90 (github.com/muncan90)
• Zicklag (github.com/zicklag)
• Greg at Unrelenting Tech (github.com/unrelentingtech)
• Eric Swanson (github.com/lachesis)
• Marcus Dansarie (github.com/dansarie)
• Marco Davids (github.com/mdavids)
• Tanner Ryan (github.com/tannerryan)

Copyright (c) 2025-2026 the Roughenough Project Contributors.

Roughenough is licensed under either of

• Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
• MIT License (http://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.