otpauth-migration-decoder.ts

import protobuf from 'protobufjs';

const migrationProto = `
syntax = "proto3";

message MigrationPayload {
  enum Algorithm {
    ALGORITHM_UNSPECIFIED = 0;
    ALGORITHM_SHA1 = 1;
    ALGORITHM_SHA256 = 2;
    ALGORITHM_SHA512 = 3;
    ALGORITHM_MD5 = 4;
  }

  enum DigitCount {
    DIGIT_COUNT_UNSPECIFIED = 0;
    DIGIT_COUNT_SIX = 1;
    DIGIT_COUNT_EIGHT = 2;
  }

  enum OtpType {
    OTP_TYPE_UNSPECIFIED = 0;
    OTP_TYPE_HOTP = 1;
    OTP_TYPE_TOTP = 2;
  }

  message OtpParameters {
    bytes secret = 1;
    string name = 2;
    string issuer = 3;
    Algorithm algorithm = 4;
    DigitCount digits = 5;
    OtpType type = 6;
    int64 counter = 7;
  }

  repeated OtpParameters otp_parameters = 1;
  int32 version = 2;
  int32 batch_size = 3;
  int32 batch_index = 4;
  int32 batch_id = 5;
}
`;

async function main(...args: string[]) {
  const [link] = args;
  
  const { root: proto } = protobuf.parse(migrationProto);
  
  const MigrationPayload = proto.lookupType('MigrationPayload');
  
  const { searchParams } = new URL(link);

  const data = searchParams.get('data');

  const encodedMessage = Buffer.from(data!, 'base64');

  const decodedMessage = MigrationPayload.decode(encodedMessage);
  
  const raw = decodedMessage.toJSON();

  console.log(JSON.stringify(raw, null, 2));
}

if (require.main === module) {
  const args = process.argv.slice(2);
  main(...args).catch((err) => {
    console.error(err);
    process.exit(1);
  });
}