Syntax

HRESULT GetAlgorithmOid(
  [in]   LONG Length,
  [in]   AlgorithmFlags AlgFlags,
  [out]  IObjectId **ppValue
);

Parameters

Length [in]

A LONG variable that identifies the required key size of the symmetric encryption algorithm. Use this parameter to retrieve a specific AES algorithm from a Cryptography API: Next Generation (CNG) key storage provider (KSP). A KSP may list only one algorithm named AES but support all of the AES variants in the following list:

• szOID_NIST_AES128_CBC (2.16.840.1.101.3.4.1.2)
• szOID_NIST_AES192_CBC (2.16.840.1.101.3.4.1.22)
• szOID_NIST_AES256_CBC (2.16.840.1.101.3.4.1.42)
• szOID_NIST_AES128_WRAP (2.16.840.1.101.3.4.1.5)
• szOID_NIST_AES192_WRAP (2.16.840.1.101.3.4.1.25)
• szOID_NIST_AES256_WRAP (2.16.840.1.101.3.4.1.45)

If you specify zero for the Length parameter and AlgorithmFlagsNone (0x00000000) for the AlgFlags parameter, the OID associated with the default algorithm is retrieved. For the Microsoft Software KSP and the Microsoft Smart Card KSP, the default AES algorithm is szOID_NIST_AES128_CBC (2.16.840.1.101.3.4.1.2).

Note  This parameter must be zero for any algorithm other than a symmetric encryption algorithm.

AlgFlags [in]

An AlgorithmFlags enumeration value that specifies whether to search for a key wrapping algorithm. This can be one of the following values:

• AlgorithmFlagsNone
• AlgorithmFlagsWrap

Specifying AlgorithmFlagsWrap causes this method to search for algorithms for which the display name ends with "wrap". This includes the following OIDs:

• szOID_NIST_AES128_WRAP (2.16.840.1.101.3.4.1.5)
• szOID_NIST_AES192_WRAP (2.16.840.1.101.3.4.1.25)
• szOID_NIST_AES256_WRAP (2.16.840.1.101.3.4.1.45)
• XCN_OID_RSA_SMIMEalgCMS3DESwrap (1.2.840.113549.1.9.16.3.6)
• XCN_OID_RSA_SMIMEalgCMSRC2wrap (1.2.840.113549.1.9.16.3.7)

If you specify zero for the Length parameter and AlgorithmFlagsNone (0x00000000) for the AlgFlags parameter, the OID associated with the default algorithm is retrieved. For the Microsoft Software KSP and the Microsoft Smart Card KSP, the default AES algorithm is szOID_NIST_AES128_CBC (2.16.840.1.101.3.4.1.2).

Note  This parameter must be zero for any algorithm other than a symmetric encryption algorithm.

ppValue [out]

Address of a variable that receives a pointer to an IObjectId interface that represents the algorithm OID.

Return Value

If the function succeeds, the function returns S_OK.

If the function fails, it returns an HRESULT value that indicates the error. Possible values include, but are not limited to, those in the following table. For a list of common error codes, see Common HRESULT Values.

Remarks

You must call the InitializeFromName method or the InitializeFromType method on the ICspInformation interface before calling GetAlgorithmOid.

Requirements

See Also

ICspAlgorithm

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Build date: 7/30/2009