---
title: kSecAttrSubjectKeyID
framework: security
role: symbol
role_heading: Global Variable
path: security/ksecattrsubjectkeyid
---

# kSecAttrSubjectKeyID

A key whose value indicates the item’s subject key ID.

## Declaration

```swift
let kSecAttrSubjectKeyID: CFString
```

## Discussion

Discussion The corresponding value is of type CFData and contains the subject key ID of a certificate. Items of class kSecClassCertificate have this attribute. Read only.