Here are the best practices for temporarily storing passwords, tokens, and credentials in managed packages: 1. **Protected Custom Settings/Metadata**: Use these to store sensitive data securely, ensuring unauthorized users or processes cannot access it. 2. **Encryption with Custom Objects**: If using custom objects, encrypt sensitive data and store the encryption key in protected custom settings or hidden custom metadata API fields. Configure permissions properly for encrypted fields. 3. **Avoid Public Storage**: Do not store sensitive data in public custom settings, metadata, or unencrypted custom objects. 4. **Named Credentials**: Use named credentials for authentication data like passwords or API tokens. Note that administrators can view these credentials, so use them for locally generated or per-org secrets. 5. **No Hard-Coding**: Avoid hard-coding sensitive data into the application. Use secure storage mechanisms and ensure sensitive data is not logged or debugged. 6. **Encryption Standards**: Implement AES-128 or higher for server-side storage of sensitive data, using vendor-provided encryption libraries. 7. **Client Applications**: Use OS vendor-supplied keychains or keystores for secure storage. Avoid storing secrets directly in the application or using insecure methods. 8. **Secure Coding Practices**: Follow secure coding practices, such as avoiding dynamic SOQL queries that could expose sensitive information. By following these practices, you can enhance the security of your managed package and protect sensitive data effectively.