/**
 * The HCA cipher type. Stored as a u16 in the `ciph` header.
 * Type 0 = plain, 1 = static obfuscation, 56 = key-derived.
 */
export type CiphType = 0 | 1 | 56;
/**
 * Build the 256-entry HCA cipher substitution table for the
 * given type and (for type 56) the two 32-bit halves of the
 * 64-bit key. The output `table` array — which must be
 * `>= 256` long — is filled in place.
 *
 * Returns `true` on success and `false` for an unrecognised
 * cipher type.
 */
export declare function initCiphTable(table: Uint8Array, type: number, key1?: number, key2?: number): boolean;
/**
 * In-place block decrypt. Each byte `b` is replaced with
 * `table[b]`. For a type-0 cipher this is a no-op (the table
 * is the identity).
 */
export declare function decryptBlock(table: Uint8Array, block: Uint8Array): void;
/**
 * Combine the user-provided 64-bit HCA key with the per-AWB
 * `awbKey` (a 16-bit "subkey" that AWB containers tack on top
 * of the file-level key). For standalone HCAs `awbKey` is 0
 * and this returns the input unchanged.
 *
 * Matches CriTools' formula:
 *   key = (key * ((awbKey << 16) | ((~awbKey & 0xFFFF) + 2))) mod 2^64
 */
export declare function combineAwbKey(key: bigint, awbKey: number): bigint;
/**
 * Split a 64-bit BigInt key into the two unsigned 32-bit halves
 * (`[lo, hi]`) used by {@link initCiphTable} for type-56.
 */
export declare function splitKey64(key: bigint): [number, number];