import { _PdfNativeAccumulatorSink, _PdfNativeHashInput } from '../digital-signature/signature/pdf-accumulator';
/**
 * SHA-1 hash implementation used internally for PDF cryptography.
 *
 * @private
 */
export declare class _Sha1 {
    /**
     * Create a chunked conversion sink for incremental hashing.
     *
     * @private
     * @param {_PdfNativeAccumulatorSink} outputSink - Sink that will receive the hash output.
     * @returns {_PdfNativeHashInput} A `_PdfNativeHashInput` for feeding chunks.
     */
    _startChunkedConversion(outputSink: _PdfNativeAccumulatorSink): _PdfNativeHashInput;
    /**
     * Rotate a 32-bit value left by `n` bits.
     *
     * @private
     * @param {number} x - Value to rotate.
     * @param {number} n - Number of bits.
     * @returns {number} The rotated value.
     */
    _rotateLeft(x: number, n: number): number;
    /**
     * Compute the SHA-1 hash for a slice of bytes.
     *
     * @private
     * @param {Uint8Array} data - Input bytes.
     * @param {number} offset - Start offset into `data`.
     * @param {number} length - Number of bytes to hash.
     * @returns {Uint8Array} The 20-byte SHA-1 digest as `Uint8Array`.
     */
    _hash(data: Uint8Array, offset: number, length: number): Uint8Array;
}