code: func NewAES256EncrypterECDSASignerEntity(ID string, b bccsp.BCCSP, encKeyBytes, signKeyBytes []byte) (*BCCSPEncrypterSignerEntity, error) {
  	if b == nil {
  		return nil, errors.New("nil BCCSP")
  	}
  
  	encKey, err := b.KeyImport(encKeyBytes, &bccsp.AES256ImportKeyOpts{Temporary: true})
  	if err != nil {
  		return nil, errors.WithMessage(err, "bccspInst.KeyImport failed")
  	}
  
  	bl, _ := pem.Decode(signKeyBytes)
  	if bl == nil {
  		return nil, errors.New("pem.Decode returns nil")
  	}
  
  	signKey, err := b.KeyImport(bl.Bytes, &bccsp.ECDSAPrivateKeyImportOpts{Temporary: true})
  	if err != nil {
  		return nil, errors.WithMessage(err, "bccspInst.KeyImport failed")
  	}
  
  	return NewEncrypterSignerEntity(ID, b, encKey, signKey, &bccsp.AESCBCPKCS7ModeOpts{}, &bccsp.AESCBCPKCS7ModeOpts{}, nil, &bccsp.SHA256Opts{})
  }
docs: // NewAES256EncrypterECDSASignerEntity returns an encrypter entity that is
  // capable of performing AES 256 bit encryption using PKCS#7 padding and
  // signing using ECDSA