secrecy.rs

use secrecy::{ExposeSecret, Secret};

#[derive(Debug)]
struct EncryptionKey(Secret<[u8; 32]>);

fn get_encryption_key() -> EncryptionKey {
    let key = EncryptionKey(Secret::new(*b"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"));
    println!("Pointer at creation: {:p}", key.0.expose_secret().as_ptr());
    key
}

fn main() {
    let encryption_key = get_encryption_key();
    let ptr = encryption_key.0.expose_secret().as_ptr();

    println!(
        "Pointer when using: {:p}",
        encryption_key.0.expose_secret().as_ptr()
    );
    println!("Using key to encrypt stuff: {:?}", encryption_key);

    println!("About to drop.");
    drop(encryption_key);
    println!("Dropped.");

    println!("memory: {:?}", unsafe {
        core::slice::from_raw_parts(ptr, 32)
    });
}

/// Output:
/// Pointer at creation: 0x7ffc1c00d2b8
/// Pointer when using: 0x7ffc1c00d2b8
/// Using key to encrypt stuff: EncryptionKey(Secret([REDACTED [u8; 32]]))
/// About to drop.
/// Dropped.
/// memory: [97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97]