export interface CanonicalSigningMessageParams {
    readonly keyId: string;
    readonly method: string;
    readonly pathnameWithSearch: string;
    readonly bodySha256Hex: string;
    readonly expUnixString: string;
    readonly nonce: string;
}
/**
 * Builds the UTF-8 message bytes signed for each proxied HTTP request.
 *
 * @remarks The format is versioned so the proxy can reject unknown schemes.
 * Keep this byte-for-byte aligned with the Cloudflare verification worker.
 *
 * @param params - Fields bound into the signing string
 * @returns UTF-8 encoded canonical message
 */
export declare function buildCanonicalSigningMessage(params: CanonicalSigningMessageParams): Uint8Array;
/**
 * Computes a lowercase hex SHA-256 digest of the given bytes.
 *
 * @param bodyBytes - Request body (empty array for no body)
 * @returns 64-character lowercase hex string
 */
export declare function sha256Hex(bodyBytes: Uint8Array): string;