@turnkey/encoding/dist/encode.js

Encoding utility functions

'use strict';

/**
 * Compresses an uncompressed P-256 public key into its 33-byte compressed form.
 *
 * @param {Uint8Array} raw - The uncompressed public key (65 bytes, starting with 0x04).
 * @returns {Uint8Array} - The compressed public key (33 bytes, starting with 0x02 or 0x03).
 * @throws {Error} - If the input key is not a valid uncompressed P-256 key.
 */
function pointEncode(raw) {
    if (raw.length !== 65 || raw[0] !== 0x04) {
        throw new Error("Invalid uncompressed P-256 key");
    }
    const x = raw.slice(1, 33);
    const y = raw.slice(33, 65);
    if (x.length !== 32 || y.length !== 32) {
        throw new Error("Invalid x or y length");
    }
    const prefix = (y[31] & 1) === 0 ? 0x02 : 0x03;
    const compressed = new Uint8Array(33);
    compressed[0] = prefix;
    compressed.set(x, 1);
    return compressed;
}

exports.pointEncode = pointEncode;
//# sourceMappingURL=encode.js.map