Struct CryptState 

pub struct CryptState {
    pub good: u32,
    pub late: u32,
    pub lost: u32,
    /* private fields */
}

A full OCB2 crypt state for one direction pair: the AES key, both IVs, the replay history and the good/late/lost counters. Mirrors Mumble’s CryptStateOCB2 object (minus key generation, which belongs to session setup).

REF: CryptStateOCB2.cpp : CryptStateOCB2, encrypt, decrypt.

Fields

good: u32

Count of successfully decrypted packets.

late: u32

Running count of late (out-of-order but recovered) packets.

lost: u32

Running count of lost packets inferred from IV gaps.

Implementations

impl CryptState

pub fn new( raw_key: &[u8; 16], encrypt_iv: &[u8; 16], decrypt_iv: &[u8; 16], ) -> Self

Build a state from a raw key and the two initial IVs.

pub fn encrypt_iv(&self) -> [u8; 16]

Current encrypt IV (mainly for tests that force/inspect IV state).

pub fn decrypt_iv(&self) -> [u8; 16]

Current decrypt IV.

pub fn set_encrypt_iv(&mut self, iv: &[u8; 16])

Overwrite the encrypt IV.

pub fn set_decrypt_iv(&mut self, iv: &[u8; 16])

Overwrite the decrypt IV.

pub fn encrypt(&mut self, plain: &[u8]) -> Option<Vec<u8>>

Encrypt a packet: advance the IV, OCB2-encrypt, and prepend the 4-byte header (IV low byte plus three tag bytes). Returns None only if encryption reports inauthenticity, which cannot happen here because the XEX* mitigation is enabled.

REF: CryptStateOCB2.cpp : CryptStateOCB2::encrypt.

pub fn decrypt(&mut self, source: &[u8]) -> Option<Vec<u8>>

Decrypt a packet, performing IV recovery for out-of-order/lost packets and rejecting replays. Returns the plaintext, or None if the packet is a replay, fails IV recovery, or fails tag verification (fail closed, R6).

REF: CryptStateOCB2.cpp : CryptStateOCB2::decrypt.