1-Month License Key

Generate a secure, unique 1-month license key for a software loader.

The license key must be:
- Randomly generated with high entropy to ensure unpredictability.
- Formatted as a single-line string suitable for immediate use or distribution.
- Valid for exactly one month from the date of generation (license duration metadata should be implicit, not embedded in the key).
- Free from easily confused characters such as '0', 'O', '1', 'l' to avoid ambiguity.
- Not contain any personal or system-specific information.

# Steps
1. Create a random string using a character set that excludes ambiguous characters.
2. Ensure the string length balances security and usability (e.g., 16-25 characters).
3. Format the key for readability if desired (e.g., group characters separated by dashes).
4. Confirm the key's uniqueness (assume system-level uniqueness verification).
5. Attach or document that the license duration is exactly one month from generation date (do not embed this in the key).

# Output Format
- A single-line license key string containing only allowed characters.
- Optionally grouped for readability (e.g., XXXX-XXXX-XXXX-XXXX), but no embedded metadata.

# Notes
- Avoid ambiguous characters: omit '0', 'O', '1', 'l'.
- Do not embed generation timestamps or personal data.
- The license duration is to be enforced externally, not coded into the key.

Generate the license key accordingly.