/**
 * Key Epoch Manager for BrightChat E2E Encryption.
 *
 * Manages versioned symmetric keys per communication context.
 * Each key rotation creates a new epoch. Messages record which
 * epoch they were encrypted under.
 *
 * epoch 0 = initial key, epoch N = Nth rotation.
 *
 * Requirements: 3.1, 3.2, 3.3, 3.4, 5.3, 2.2, 5.2
 */
/**
 * Tracks key epochs for a communication context.
 *
 * encryptedEpochKeys: Map<epoch, Map<memberId, wrappedKey>>
 */
export interface IKeyEpochState<TData = Uint8Array> {
    currentEpoch: number;
    /** epoch → raw symmetric key (server-side only, in-memory) */
    epochKeys: Map<number, Uint8Array>;
    /** epoch → memberId → wrapped key (persisted) */
    encryptedEpochKeys: Map<number, Map<string, TData>>;
}
export declare class KeyEpochManager {
    /**
     * Initialize epoch state for a new context.
     * Creates epoch 0 with the given symmetric key, wraps for all members.
     */
    static createInitial(symmetricKey: Uint8Array, memberIds: string[], encryptKeyForMembers: (ids: string[], key: Uint8Array) => Map<string, Uint8Array>): IKeyEpochState;
    /**
     * Rotate: increment epoch, add new key, delete removed member from ALL epochs,
     * re-wrap ALL epoch keys for remaining members.
     */
    static rotate(state: IKeyEpochState, newKey: Uint8Array, remainingMemberIds: string[], removedMemberId: string, encryptKeyForMembers: (ids: string[], key: Uint8Array) => Map<string, Uint8Array>): IKeyEpochState;
    /**
     * Add a member: wrap ALL epoch keys for the new member
     * so they can read history.
     */
    static addMember(state: IKeyEpochState, newMemberId: string, encryptKeyForMember: (memberId: string, key: Uint8Array) => Uint8Array): void;
}
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