Function open_sealed_box

sodiumbox/src/lib.rs:137–170

(
    sealed_box: &[u8],
    public_key: &PublicKey,
    secret_key: &StaticSecret,
)

/// * `Err(())` - Decryption error (invalid format, authentication failure, etc.)
#[allow(clippy::result_unit_err)]
pub fn open_sealed_box(
    sealed_box: &[u8],
    public_key: &PublicKey,
    secret_key: &StaticSecret,
) -> Result<Vec<u8>, ()> {
    if sealed_box.len() <= PUBLICKEYBYTES {
        return Err(());
    }

    let ephemeral_pk_bytes = &sealed_box[..PUBLICKEYBYTES];
    let ciphertext = &sealed_box[PUBLICKEYBYTES..];

    // Derive the nonce using the ephemeral public key and recipient's public key
    let nonce = derive_nonce(ephemeral_pk_bytes, public_key.as_bytes())?;

    // Convert ephemeral public key bytes to x25519-dalek type
    let ephemeral_pk_array = <[u8; 32]>::try_from(ephemeral_pk_bytes).map_err(|_| ())?;
    let ephemeral_pk = PublicKey::from(ephemeral_pk_array);

    // Compute the shared secret using X25519 Diffie-Hellman
    let shared_secret = secret_key.diffie_hellman(&ephemeral_pk);

    // Derive the symmetric key using HSalsa20
    let key_bytes = derive_key(shared_secret.as_bytes());

    // Create the XSalsa20Poly1305 cipher with the derived key
    let cipher = XSalsa20Poly1305::new_from_slice(&key_bytes).map_err(|_| ())?;

    // Decrypt the ciphertext
    match cipher.decrypt(&nonce, ciphertext) {
        Ok(pt) => Ok(pt),
        Err(_) => Err(()),
    }
}

/// Convenience function to convert a public key from bytes to the PublicKey type
pub fn public_key_from_bytes(bytes: &[u8; 32]) -> PublicKey {