@coti-io/coti-sdk-typescript/dist/bytes.js

A library for encryption, decryption and cryptographic utilities for the COTI blockchain.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ciphertextBytesToCtUint256 = exports.ctUint256ToBytes = exports.ctUintToBytes = exports.bytesToHex = exports.bytesToBigint = exports.bigintToBytesBE = exports.CT_SIZE = exports.HEX_BASE = void 0;
/** Radix used for hex encoding/decoding in this module. */
exports.HEX_BASE = 16;
/** Byte length of a single {@link ctUint} on the wire (ciphertext + random `r`). */
exports.CT_SIZE = 32;
/**
 * Encodes an unsigned bigint as a fixed-width big-endian byte array.
 *
 * @param value - Integer to encode.
 * @param width - Output length in bytes; leading zero bytes are emitted as needed.
 * @returns Big-endian bytes of length `width`.
 */
function bigintToBytesBE(value, width) {
    const bytes = new Uint8Array(width);
    for (let i = width - 1; i >= 0; i--) {
        bytes[i] = Number(value & BigInt(0xff));
        value >>= BigInt(8);
    }
    return bytes;
}
exports.bigintToBytesBE = bigintToBytesBE;
/**
 * Decodes a big-endian byte array into an unsigned bigint.
 *
 * @param bytes - Non-empty byte array to decode.
 * @returns Unsigned integer represented by `bytes`.
 * @throws SyntaxError if `bytes` is empty.
 */
function bytesToBigint(bytes) {
    return BigInt("0x" + bytesToHex(bytes));
}
exports.bytesToBigint = bytesToBigint;
/**
 * Encodes bytes as a lowercase hex string (two digits per byte).
 *
 * @param bytes - Byte array to encode.
 * @returns Hex string without `0x` prefix.
 */
function bytesToHex(bytes) {
    return Array.from(bytes)
        .map(byte => byte.toString(exports.HEX_BASE).padStart(2, '0'))
        .join('');
}
exports.bytesToHex = bytesToHex;
/**
 * Serializes a {@link ctUint} bigint to its 32-byte on-wire representation.
 *
 * @param ciphertext - ctUint value as a bigint.
 * @returns 32-byte big-endian blob ({@link CT_SIZE} bytes).
 */
function ctUintToBytes(ciphertext) {
    return bigintToBytesBE(ciphertext, exports.CT_SIZE);
}
exports.ctUintToBytes = ctUintToBytes;
/**
 * Serializes a {@link ctUint256} to a 64-byte concatenation of its two ctUint limbs.
 *
 * @param ciphertext - ctUint256 with `ciphertextHigh` and `ciphertextLow`.
 * @returns 64-byte buffer: high limb (32 B) followed by low limb (32 B).
 */
function ctUint256ToBytes(ciphertext) {
    return new Uint8Array([
        ...ctUintToBytes(ciphertext.ciphertextHigh),
        ...ctUintToBytes(ciphertext.ciphertextLow)
    ]);
}
exports.ctUint256ToBytes = ctUint256ToBytes;
/**
 * Parses a 64-byte ciphertext blob into a {@link ctUint256} object.
 *
 * @param ciphertext - 64-byte buffer (typically from encryption helpers).
 * @returns ctUint256 with `ciphertextHigh` and `ciphertextLow` bigints.
 */
function ciphertextBytesToCtUint256(ciphertext) {
    return {
        ciphertextHigh: bytesToBigint(ciphertext.slice(0, exports.CT_SIZE)),
        ciphertextLow: bytesToBigint(ciphertext.slice(exports.CT_SIZE))
    };
}
exports.ciphertextBytesToCtUint256 = ciphertextBytesToCtUint256;