Concerns Regarding Entropy in Password Generation with Character Restrictions about go-password HOT 1 CLOSED

However, the restriction that disallows repeated characters and the requirement for a fixed number of digits and special characters may inadvertently reduce the entropy of the generated passwords.

This isn't a "restriction", it's a user-specified configuration based on the use case. If your use case requires extremely high entropy or a larger character set (technically emojis and any unicode character could be valid), then you can customize this configurable.

I'm not really sure what change you're suggesting here. Users can allow characters to repeat. I'm not taking away that configuration option.

Finally, if you really want the highest entropy with no constraints, just read cryto.Rand into a []byte that's allocated with your preset length and encode the result as hex or base64:

buf := make([]byte, length)
n, err := rand.Read(buf) // crypto/rand
if err != nil {
  panic(err)
}
if n < length {
  panic(fmt.Sprintf("insufficient bytes read: %v, expected %v", n, length))
}
return buf, nil

This library (and it's sister library go-diceware) are intentionally low-level and configurable libraries.

from go-password.