message: Change key scope.
diff: @@ -18,7 +18,6 @@ import { SecureString } from './secureString';
  const TAG_DELIMITER = ':';
  const BYTE_COUNT_FOR_IV = 6;
  const _algo = 'aes-256-gcm';
  -const _key: SecureString<string> = new SecureString();
  const KEY_NAME = 'sfdx';
  const ACCOUNT = 'local';
  @@ -71,6 +70,7 @@ export class Crypto {
  private messages: Messages;
  private noResetOnClose: boolean;
  + private _key: SecureString<string> = new SecureString();
  constructor(private keyChain?) { }
  @@ -93,7 +93,7 @@ export class Crypto {
  this.noResetOnClose = noResetOnClose;
  try {
  - _key.consume(Buffer.from((await keychainPromises.getPassword(await this.getKeyChain(platform), KEY_NAME, ACCOUNT)).password, 'utf8'));
  + this._key.consume(Buffer.from((await keychainPromises.getPassword(await this.getKeyChain(platform), KEY_NAME, ACCOUNT)).password, 'utf8'));
  return this;
  } catch (err) {
  // No password found
  @@ -128,14 +128,14 @@ export class Crypto {
  return undefined;
  }
  - if (isNil(_key)) {
  + if (isNil(this._key)) {
  const errMsg = this.messages.getMessage('KeychainPasswordCreationError');
  throw new SfdxError(errMsg, 'KeychainPasswordCreationError');
  }
  const iv = crypto.randomBytes(BYTE_COUNT_FOR_IV).toString('hex');
  - return _key.value((buffer: Buffer): string => {
  + return this._key.value((buffer: Buffer): string => {
  const cipher = crypto.createCipheriv(_algo, buffer.toString('utf8'), iv);
  let encrypted = cipher.update(text, 'utf8', 'hex');
  @@ -169,7 +169,7 @@ export class Crypto {
  const iv = tokens[0].substring(0, (BYTE_COUNT_FOR_IV * 2));
  const secret = tokens[0].substring((BYTE_COUNT_FOR_IV * 2), tokens[0].length);
  - return _key.value((buffer: Buffer) => {
  + return this._key.value((buffer: Buffer) => {
  const decipher = crypto.createDecipheriv(_algo, buffer.toString('utf8'), iv);
  let dec;
  @@ -187,7 +187,7 @@ export class Crypto {
  public close(): void {
  if (!this.noResetOnClose) {
  - _key.clear();
  + this._key.clear();
  }
  }
  