  sign: (() => {
    if (typeof sign_ === 'function') {
      return function sign(data, algo) {
        const pem = this[SYM_PRIV_PEM];
        if (pem === null)
          return new Error('No private key available');
        if (!algo || typeof algo !== 'string')
          algo = this[SYM_HASH_ALGO];
        try {
          return sign_(algo, data, pem);
        } catch (ex) {
          return ex;
        }
      };
    }
    return function sign(data, algo) {
      const pem = this[SYM_PRIV_PEM];
      if (pem === null)
        return new Error('No private key available');
      if (!algo || typeof algo !== 'string')
        algo = this[SYM_HASH_ALGO];
      const signature = createSign(algo);
      signature.update(data);
      try {
        return signature.sign(pem);
      } catch (ex) {
        return ex;
      }
    };
  })(),
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.