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# CMSSignedAttributes

Optional attributes you can add to a signed message.

```
struct CMSSignedAttributes
```

## Overview

Use these flags with the [`CMSEncoderAddSignedAttributes(_:_:)`](/documentation/Security/CMSEncoderAddSignedAttributes(_:_:)) method to cause the encoder to add attributes to a signed message that can be interpreted by the recipient. These attributes are not used for unsigned messages.

## Topics

### Attributes

[`kCMSAttrNone`](/documentation/Security/CMSSignedAttributes/kCMSAttrNone)

No attributes.

[`attrSmimeCapabilities`](/documentation/Security/CMSSignedAttributes/attrSmimeCapabilities)

Identify signature, encryption, and digest algorithms supported by the encoder.

[`attrSmimeEncryptionKeyPrefs`](/documentation/Security/CMSSignedAttributes/attrSmimeEncryptionKeyPrefs)

Indicate that the signing certificate included with the message is the preferred one for S/MIME encryption.

[`attrSmimeMSEncryptionKeyPrefs`](/documentation/Security/CMSSignedAttributes/attrSmimeMSEncryptionKeyPrefs)

Indicate that the signing certificate included with the message is the preferred one for S/MIME encryption, but using an attribute object identifier (OID) preferred by Microsoft.

[`attrSigningTime`](/documentation/Security/CMSSignedAttributes/attrSigningTime)

Include the signing time.

[`attrAppleCodesigningHashAgility`](/documentation/Security/CMSSignedAttributes/attrAppleCodesigningHashAgility)

Include Apple codesigning hash agility.

[`attrAppleCodesigningHashAgilityV2`](/documentation/Security/CMSSignedAttributes/attrAppleCodesigningHashAgilityV2)

Include Apple codesigning hash agility, version 2.

[`attrAppleExpirationTime`](/documentation/Security/CMSSignedAttributes/attrAppleExpirationTime)

Include the expiration time.

### Initializers

[`init(rawValue:)`](/documentation/Security/CMSSignedAttributes/init(rawValue:))

Initializes a new attributes structure.


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