Function generate_token 

pub fn generate_token(n_bytes: usize) -> String

Available on crate feature crypto only.

Generate n_bytes of cryptographically secure random bytes and return them as a lowercase hex string of length n_bytes * 2.

Suitable for password-reset tokens, email verification codes, and API keys. Use at least 16 bytes (32 hex chars) for tokens; 32 bytes (64 hex chars) for high-value secrets like API keys.