GenerateKey
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SYNOPSIS
# include <cssm.h>
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API PARAMETERS
| CCHandle (input) | The handle that describes the context of this cryptographic operation used to link to the CSP-managed information. | |
| KeyUsage (input) | A bit mask indicating all permitted uses for the new key. | |
| KeyAttr (input) | A bit mask defining attribute values for the new key. | |
| KeyLabel (input/optional) | ||
Pointer to a byte string that will be used as the label for the 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 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 an empty list. | ||
| Key (output) | Pointer to CSSM_KEY structure used to hold the new key. The CSSM_KEY structure should be empty upon input to this function. The CSP will ignore any values residing in this structure at function invocation. Input values should be supplied in the cryptographic context, KeyUsage, KeyAttr, and KeyLabel input parameters. | |
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. | |
| Key (output) | Pointer to CSSM_KEY structure used to obtain the key. Upon function invocation, any values in the CSSM_Key structure should be ignored. All input values should be supplied in the cryptographic Context, KeyUsage, KeyAttr, and KeyLabel input parameters. | |
DESCRIPTION
This function generates a symmetric key. The KeyUsage, and KeyAttr are used to initialize the keyheader for the newly created key. These values are not retained in the cryptographic Context, which contains additional parameters for this operation. The CSP may cache keying material associated with the new symmetric key. When the symmetric key is no longer in active use, the application can invoke the CSSM_FreeKey() interface to allow cached keying material associated with the symmetric key to be removed.
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.
NOTES
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), function or with the memory functions registered for the CSPHandle.