/**
 * Extract public key from a did:key DID
 *
 * Format: did:key:z6Mk... where z6Mk is base58btc encoded with multicodec prefix
 *
 * @param did - The DID to extract the public key from
 * @returns The 32-byte Ed25519 public key
 * @throws Error if DID format is invalid
 */
export declare function didKeyToPublicKey(did: string): Uint8Array;
/**
 * Verify an Ed25519 signature
 *
 * @param message - The message that was signed
 * @param signature - The signature to verify
 * @param publicKey - The public key to verify against
 * @returns True if signature is valid
 */
export declare function verifySignature(message: Uint8Array, signature: Uint8Array, publicKey: Uint8Array): Promise<boolean>;
/**
 * Decode base64url to Uint8Array
 *
 * @param str - Base64url encoded string
 * @returns Decoded bytes
 */
export declare function base64UrlDecode(str: string): Uint8Array;
/**
 * Encode Uint8Array to base64url
 *
 * @param data - Bytes to encode
 * @returns Base64url encoded string
 */
export declare function base64UrlEncode(data: Uint8Array): string;
/**
 * Generate a secure random nonce
 *
 * @param length - Length in bytes (default: 32)
 * @returns Base64url encoded nonce
 */
export declare function generateNonce(length?: number): string;
//# sourceMappingURL=index.d.ts.map