---
title: tag
framework: cryptokit
role: symbol
role_heading: Instance Property
path: cryptokit/aes/gcm/sealedbox/tag
---

# tag

An authentication tag.

## Declaration

```swift
var tag: Data { get }
```

## Discussion

Discussion The authentication tag has a length of 16 bytes.

## See Also

### Inspecting the component elements

- [nonce](cryptokit/aes/gcm/sealedbox/nonce.md)
- [ciphertext](cryptokit/aes/gcm/sealedbox/ciphertext.md)