Certwatch

TLS certificate expiration checker.

School Purpose Only.

Overview

Certwatch is a polished educational cybersecurity utility by LayerByte. It focuses on one practical defensive concept and keeps the implementation small enough for students to read, run, and understand.

Expired certificates cause outages, so expiration checks are a practical defensive administration habit.

Highlights

• Checks certificate expiration
• Uses network timeouts
• Reports days remaining

Feature Set

• Clear command-line or local application workflow
• Beginner-readable validation and error handling
• Copy-friendly output for notes, screenshots, and reports
• Conservative behavior designed around local or authorized data
• No exploit code, malware behavior, credential theft, brute forcing, or destructive actions

Supported Inputs

• Hostnames
• TLS endpoints the user is authorized to check

Requirements

• Go 1.22 or newer

Installation

Clone the repository and open the project folder:

git clone https://github.com/LayerByte/certwatch.git
cd certwatch

Then prepare the project with the standard toolchain:

go mod tidy
go build ./...

Usage

Start with the help command or the default run command:

go run . --help

Example Workflow

1. Open the project folder.
2. Run the help command.
3. Provide a small authorized sample input.
4. Review the report and compare it with the source code.

Example run:

go run . --help

Expected Output

A certificate validity report with expiration status.

Output is intended to be readable in the terminal or application window and easy to copy into a school report or defensive analysis note.

Safety Scope

• Use only on systems, files, domains, and data you own or have permission to inspect.
• Treat paths, hostnames, hashes, and log entries as potentially sensitive before sharing output.
• Prefer small sample files when learning how the tool works.
• Do not use the project for unauthorized scanning, exploitation, credential attacks, persistence, evasion, or destructive activity.

Learning Goals

• Practice safe input validation and graceful error messages.
• Understand the defensive concept behind the tool.
• Learn how a focused security utility is organized in Go.
• Compare raw input with structured output.
• Build habits around permission, documentation, and responsible testing.

Development Notes

Keep packages focused, use timeouts for network operations, and return clear errors instead of hiding failures.

Suggested checks before publishing changes:

# Run the help command.
# Test with a small non-sensitive sample.
# Confirm errors are clear when input is missing or invalid.

Troubleshooting

• If the command is not found, confirm the required toolchain is installed and available in your PATH.
• If a file cannot be opened, check the path, permissions, and whether another program is locking it.
• If a network-focused check fails, verify the hostname, scheme, connection, and permission to test that endpoint.
• If output looks empty, retry with a smaller known-good sample input.

Known Limitations

• Built for education and small authorized workflows, not enterprise monitoring.
• Results depend on operating system permissions, platform APIs, and sample quality.
• Some advanced features are intentionally omitted to keep the code approachable.
• Findings should be reviewed by a human before making security decisions.

Disclaimer

This project is for defensive learning, school assignments, and authorized administration. It does not include malware, credential theft, brute-force attacks, exploitation, payload delivery, persistence, bypass functionality, or unauthorized access functionality.

License

Released under the MIT License.