---
title: CSSM_CHALLENGE_CALLBACK
framework: Security
role: symbol
role_heading: Type Alias
platforms: [macOS 10.0+]
path: security/cssm_challenge_callback
---

# CSSM_CHALLENGE_CALLBACK

## Declaration

```occ
typedef int (*)(const struct cssm_list *, struct cssm_samplegroup *, void *, const struct cssm_memory_funcs *) CSSM_CHALLENGE_CALLBACK;
```