---
title: "SecDigestTransformCreate(_:_:_:)"
framework: security
role: symbol
role_heading: Function
path: "security/secdigesttransformcreate(_:_:_:)"
---

# SecDigestTransformCreate(_:_:_:)

Creates a digest transform object.

## Declaration

```swift
func SecDigestTransformCreate(_ digestType: CFTypeRef?, _ digestLength: CFIndex, _ error: UnsafeMutablePointer<Unmanaged<CFError>?>?) -> SecTransform
```

## Parameters

- `digestType`: The type of digest to compute. You may pass NULL for this parameter, in which case an appropriate algorithm will be chosen for you. Otherwise, use one of the values listed in Digest Constants.
- `digestLength`: The desired digest length. Note that certain algorithms may only support certain sizes. You may pass 0 for this parameter, in which case an appropriate length will be chosen for you.
- `error`: A pointer to a doc://com.apple.documentation/documentation/CoreFoundation/CFError. This pointer will be set if an error occurred. This value may be nil if you do not want an error returned.

## Return Value

Return Value A pointer to a new transform or NULL on error. In Objective-C, call the CFRelease function to free this object’s memory when you are done with it.

## Discussion

Discussion This function creates a transform which computes a cryptographic digest.