/**
 * @fileoverview MembershipProofService — generates and verifies ring signatures
 * proving BrightTrust membership without revealing which specific member created content.
 *
 * Uses an Abe-Ohkubo-Suzuki (AOS) style ring signature scheme built on
 * secp256k1 ECDSA primitives. The proof is bound to a specific content hash,
 * preventing reuse across different content items.
 *
 * Ring Signature Scheme:
 * - For a ring of n public keys, the signer (at index s) generates a ring
 *   of challenges and responses such that the verification equation holds
 *   for all members, but only the signer knows which position is theirs.
 * - The challenge chain is: c_{i+1} = H(L || m || g^{r_i} * y_i^{c_i})
 *   where L is the key set, m is the message, g is the generator, y_i is
 *   the public key at index i, r_i is the response, and c_i is the challenge.
 * - The ring closes when c_0 (computed) matches c_0 (stored).
 *
 * @see Requirements 18
 * @see Design: MembershipProofService (Section 7)
 */
import { PlatformID } from '@digitaldefiance/ecies-lib';
import { IMembershipProofService } from '../interfaces/services/membershipProof';
/**
 * MembershipProofService generates and verifies ring signatures
 * proving BrightTrust membership without revealing which member.
 *
 * The ring signature scheme ensures:
 * - Any member can generate a valid proof
 * - The proof is bound to specific content (content hash)
 * - Verification succeeds against the full member key set
 * - No information about which member generated the proof is leaked
 *
 * Proof format (serialized):
 * [version: 1 byte] [n: 2 bytes (uint16 BE)] [c0: 32 bytes] [r0: 32 bytes] ... [r_{n-1}: 32 bytes]
 *
 * @template TID - Platform ID type for frontend/backend DTO compatibility
 */
export declare class MembershipProofService<TID extends PlatformID = Uint8Array> implements IMembershipProofService<TID> {
    /** Generic marker for DTO compatibility */
    _platformId?: TID;
    /**
     * Generate a ring signature proving the signer is one of the current
     * BrightTrust members. The proof is bound to the specific content hash.
     *
     * Algorithm (AOS ring signature):
     * 1. Find signer's index s in the key ring
     * 2. Generate random k (nonce) for the signer's position
     * 3. Compute initial point: g^k
     * 4. For positions (s+1) to (s-1) mod n, generate random responses
     *    and compute the challenge chain
     * 5. Close the ring by computing the signer's response:
     *    r_s = k - c_s * privateKey mod n
     *
     * @param signerPrivateKey - The signer's secp256k1 private key (32 bytes)
     * @param memberPublicKeys - Public keys of all current BrightTrust members
     * @param contentHash - Hash of the content being signed
     * @returns The serialized ring signature proof
     * @throws Error if signer is not in the member set or member set is empty
     */
    generateProof(signerPrivateKey: Uint8Array, memberPublicKeys: Uint8Array[], contentHash: Uint8Array): Promise<Uint8Array>;
    /**
     * Verify a membership proof against the current member set and content hash.
     *
     * Algorithm:
     * 1. Deserialize the proof to extract c_0 and all responses
     * 2. Recompute the challenge chain starting from c_0:
     *    For each i: point_i = g^{r_i} * y_i^{c_i}, c_{i+1} = H(L, m, point_i)
     * 3. The ring is valid if the recomputed c_0 matches the stored c_0
     *
     * @param proof - The serialized ring signature proof
     * @param memberPublicKeys - Public keys of all current BrightTrust members
     * @param contentHash - Hash of the content the proof should be bound to
     * @returns True if the proof is valid
     */
    verifyProof(proof: Uint8Array, memberPublicKeys: Uint8Array[], contentHash: Uint8Array): Promise<boolean>;
    /**
     * Serialize a ring signature proof into bytes.
     *
     * Format:
     * [version: 1 byte] [n: 2 bytes uint16 BE] [c0: 32 bytes] [r_0: 32 bytes] ... [r_{n-1}: 32 bytes]
     */
    private serializeProof;
    /**
     * Deserialize a ring signature proof from bytes.
     *
     * @returns Parsed proof components or null if the format is invalid
     */
    private deserializeProof;
}
//# sourceMappingURL=membershipProofService.d.ts.map