NAME
   DeriveKey,
   CSSM_DeriveKey,
   CSP_DeriveKey   - Derive new symmetric key (CDSA)

 SYNOPSIS
   # include <cssm.h>

    API:
        CSSM_RETURN CSSMAPI CSSM_DeriveKey
        (CSSM_CC_HANDLE CCHandle,
        CSSM_DATA_PTR Param,
        uint32 KeyUsage,
        uint32 KeyAttr,
        const CSSM_DATA *KeyLabel,
        const CSSM_RESOURCE_CONTROL_CONTEXT *CredAndAclEntry,
        CSSM_KEY_PTR DerivedKey)
    SPI:
        CSSM_RETURN CSSMCSPI CSP_DeriveKey
        (CSSM_CSP_HANDLE CSPHandle,
        CSSM_CC_HANDLE CCHandle,
        const CSSM_CONTEXT *Context,
        CSSM_DATA_PTR Param,
        uint32 KeyUsage,
        uint32 KeyAttr,
        const CSSM_DATA *KeyLabel,
        const CSSM_RESOURCE_CONTROL_CONTEXT *CredAndAclEntry,
        CSSM_KEY_PTR DerivedKey)

 LIBRARY
   Common Security Services Manager library (CDSA$INCSSM300_SHR.EXE)

 API PARAMETERS
   CCHandle (input)
           The handle that describes the context of this cryptographic
           operation.

   Param (input/output)
           This parameter varies depending on the derivation algorithm.
           Password based derivation algorithms use this parameter to
           return a cipher block chaining initialization vector.
           Concatenation algorithms use this parameter to get the second
           item to concatenate.

   KeyUsage (input)
           A bit mask indicating all permitted uses for the new derived
           key.

   KeyAttr (input)
           A bit mask defining other attribute values for the new derived
           key.

   KeyLabel (input/optional)
           Pointer to a byte string that will be used as the label for the
           derived key.

   CredAndAclEntry (input/optional)
           A structure containing one or more credentials authorized for
           creating a key and the prototype ACL entry that will control
           future use of the newly created key. The credentials and ACL
           entry prototype can be presented as immediate values or
           callback functions can be provided for use by the CSP to
           acquire the credentials and/or the subject of the ACL entry
           interactively. If the CSP provides public access for creating
           a key, then the credentials can be NULL. If the CSP defines a
           default initial ACL entry for the new key, then the ACL entry
           prototype can be empty.

   DerivedKey (output)
           A pointer to a CSSM_KEY structure that returns the derived key.

 SPI PARAMETERS
   CSPHandle (input)
           The handle that describes the add-in cryptographic service
           provider module used to perform up calls to CSSM for the
           memory functions managed by CSSM.

   Context (input)
           Pointer to CSSM_CONTEXT structure that describes the attributes
           with this context.

 DESCRIPTION
   This function derives a new symmetric key using the context and/or
   information from the base key in the context. The CSP can require that
   the cryptographic context include access credentials for authentication
   and authorization checks when using a private key or a secret key.

   Authorization policy can restrict the set of callers who can create a
   new resource. In this case, the caller must present a set of access
   credentials for authorization. Upon successfully authenticating the
   credentials, the template that verified the presented samples
   identifies the ACL entry that will be used in the authorization
   computation. If the caller is authorized, the new resource is created.

   The caller must provide an initial ACL entry to be associated with
   the newly created resource. This entry is used to control future
   access to the new resource and (since the subject is deemed to be
   the "Owner") exercise control over its associated ACL. The caller
   can specify the following items for initializing an ACL entry:

   Subject A CSSM_LIST structure, containing the type of the subject
           and a template value that can be used to verify samples that
           are presented in credentials when resource access is requested.

   Delegation flag
           A value indicating whether the Subject can delegate the
           permissions recorded in the AuthorizationTag. (This item
           only applies to public key subjects).

   Authorization tag
           The set of permissions that are granted to the Subject.

   Validity period
           The start time and the stop time for which the ACL entry is
           valid.

   ACL entry tag
           A user-defined string value associated with the ACL entry.

           The service provider can modify the caller-provided initial
           ACL entry to conform to any innate resource-access policy
           that the service provider may be required to enforce. If the
           initial ACL entry provided by the caller contains values or
           permissions that are not supported by the service provider,
           then the service provider can modify the initial ACL
           appropriately or can fail the request to create the new
           resource. Service providers list their supported
           AuthorizationTag values in their Module Directory Services
           primary record.

           The CSP can require that the cryptographic context include
           access credentials for authentication and authorization
           checks when using a private key or a secret key.

 RETURN VALUE
   A CSSM_RETURN value indicating success or specifying a particular
   error condition. The value CSSM_OK indicates success. All other
   values represent an error condition.

 ERRORS
   Errors are described in the CDSA technical standard.  See CDSA.

        CSSMERR_CSP_KEY_LABEL_ALREADY_EXISTS

 COMMENTS
   The KeyData field of the CSSM_KEY structure is allocated by the CSP.
   The application is required to free this memory using the
   CSSM_FreeKey() (CSSM API), or CSP_FreeKey() (CSP SPI) call, or with
   the memory functions registered for the CSPHandle.

 SEE ALSO
   Books

   Intel CDSA Application Developer's Guide (see CDSA)

   Other Help Topics

   Functions: CSSM_CSP_CreateDeriveKeyContext