@polkadot/keyring/pair/decode.js

import { u8aEq } from '@polkadot/util';
import { jsonDecryptData } from '@polkadot/util-crypto';
import { PKCS8_DIVIDER, PKCS8_HEADER, PUB_LENGTH, SEC_LENGTH, SEED_LENGTH } from './defaults.js';
const SEED_OFFSET = PKCS8_HEADER.length;
export function decodePair(passphrase, encrypted, _encType) {
    const encType = Array.isArray(_encType) || _encType === undefined
        ? _encType
        : [_encType];
    const decrypted = jsonDecryptData(encrypted, passphrase, encType);
    const header = decrypted.subarray(0, PKCS8_HEADER.length);
    if (!u8aEq(header, PKCS8_HEADER)) {
        throw new Error('Invalid Pkcs8 header found in body');
    }
    let secretKey = decrypted.subarray(SEED_OFFSET, SEED_OFFSET + SEC_LENGTH);
    let divOffset = SEED_OFFSET + SEC_LENGTH;
    let divider = decrypted.subarray(divOffset, divOffset + PKCS8_DIVIDER.length);
    // old-style, we have the seed here
    if (!u8aEq(divider, PKCS8_DIVIDER)) {
        divOffset = SEED_OFFSET + SEED_LENGTH;
        secretKey = decrypted.subarray(SEED_OFFSET, divOffset);
        divider = decrypted.subarray(divOffset, divOffset + PKCS8_DIVIDER.length);
        if (!u8aEq(divider, PKCS8_DIVIDER)) {
            throw new Error('Invalid Pkcs8 divider found in body');
        }
    }
    const pubOffset = divOffset + PKCS8_DIVIDER.length;
    const publicKey = decrypted.subarray(pubOffset, pubOffset + PUB_LENGTH);
    return {
        publicKey,
        secretKey
    };
}