What are the best practices for security in Go, both at the code and architecture levels?

Code level security best practices

1. Use strong typing

Go is a statically typed language, which can help you catch common mistakes and type-related bugs at compile time. Be explicit about your types to avoid surprises during runtime.

2. Avoid using ’unsafe’ package

The unsafe package in Go allows bypassing type safety and memory protection features, and it should be avoided as much as possible. If you must use it, ensure that you understand the risks involved and thoroughly review the code.

3. Check errors and return values accurately

In Go, functions often return errors, and it is your responsibility to handle them properly. Don’t ignore or suppress errors, as they can lead to security vulnerabilities.

4. Securely store sensitive data

Use secure methods for storing passwords or other sensitive data. Avoid storing plain-text passwords or other sensitive data in the source code. You can use bcrypt to encrypt sensitive data.

5. Validate input

Always validate and sanitize any input coming from external sources, such as user input or data received from other systems. This helps to prevent potential security vulnerabilities like SQL injection, XSS, or other attacks. Use the appropriate functions in Go’s standard library to sanitize input.

Architecture level security best practices

1. Use HTTPS for communication

Use HTTPS and TLS to encrypt all data transmitted between client and server. This can help protect sensitive data, such as login credentials, personal information, or financial data, from being intercepted during transit.

2. Regularly update dependencies

Keep the Go runtime and all libraries you depend on up-to-date, as older versions may have known security vulnerabilities.

3. Implement authentication, authorization, and access control

Implement proper authentication, authorization, and access control mechanisms in your application. Use libraries like OAuth2, OpenID Connect, or JWT for handling authentications and authorizations.

4. Use secure development frameworks

Leverage secure development frameworks like Gorilla, Revel, or Echo which offer built-in security features such as CSRF protection, XSS protection, and CORS middleware.

5. Apply the principle of least privilege

Give users and services the minimum permissions they need to perform their tasks, and nothing more. This can significantly limit the damage an attacker can cause if they compromise a component of your system.

6. Log and monitor

Implement a robust logging and monitoring system to detect suspicious activities or anomalies. This can help identify potential security issues and provide information for forensic analysis in the event of a breach.

In summary, you should follow a combination of code and architecture level best practices to ensure the highest level of security in your Go applications. Strong typing, error handling in your code, and secure protocols are fundamental facets. Additionally, make use of well-tested libraries and development frameworks, alongside implementing proper authentication and access controls, to make your system less prone to attacks.