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# System Identity Domains

Set or obtain a system identity for domains.

## Discussion

These constants can be used with the [`SecIdentitySetSystemIdentity(_:_:)`](/documentation/Security/SecIdentitySetSystemIdentity(_:_:)) and [`SecIdentityCopySystemIdentity(_:_:_:)`](/documentation/Security/SecIdentityCopySystemIdentity(_:_:_:)) functions.

## Topics

### Constants

[`let kSecIdentityDomainDefault: CFString`](/documentation/Security/kSecIdentityDomainDefault)

The system-wide default identity.

[`let kSecIdentityDomainKerberosKDC: CFString`](/documentation/Security/kSecIdentityDomainKerberosKDC)

Kerberos Key Distribution Center (KDC) identity.


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