CRYPT_OID_INFO structure (wincrypt.h)

  • Article

The CRYPT_OID_INFO structure contains information about an object identifier (OID). These structures give the relationship among an OID identifier, its name, its group, and other information about the OID. These structures can be listed by using the CryptEnumOIDInfo function. New CRYPT_OID_STRUCTURES can be added by using the CryptRegisterOIDInfo function.

Syntax

typedef struct _CRYPT_OID_INFO {
  DWORD           cbSize;
  LPCSTR          pszOID;
  LPCWSTR         pwszName;
  DWORD           dwGroupId;
  union {
    DWORD  dwValue;
    ALG_ID Algid;
    DWORD  dwLength;
  } DUMMYUNIONNAME;
  CRYPT_DATA_BLOB ExtraInfo;
  LPCWSTR         pwszCNGAlgid;
  LPCWSTR         pwszCNGExtraAlgid;
} CRYPT_OID_INFO, *PCRYPT_OID_INFO;

Members

cbSize

The size, in bytes, of this structure.

pszOID

The OID associated with this OID information.

pwszName

The display name associated with an OID.

dwGroupId

The group identifier value associated with this OID information.

This member can be one of the following dwGroupId group identifiers.

Value Meaning
CRYPT_ENCRYPT_ALG_OID_GROUP_ID
 Encryption algorithms
CRYPT_ENHKEY_USAGE_OID_GROUP_ID
 Enhanced key usages
CRYPT_EXT_OR_ATTR_OID_GROUP_ID
 Extensions or attributes
CRYPT_HASH_ALG_OID_GROUP_ID
 Hash algorithms
CRYPT_POLICY_OID_GROUP_ID
 Policies
CRYPT_PUBKEY_ALG_OID_GROUP_ID
 Public key algorithms
CRYPT_RDN_ATTR_OID_GROUP_ID
 RDN attributes
CRYPT_SIGN_ALG_OID_GROUP_ID
 Signature algorithms

DUMMYUNIONNAME

DUMMYUNIONNAME.dwValue

A numeric value associated with this OID information. This member is used with dwGroupId CRYPT_SIGN_ALG_OID_GROUP_ID.

DUMMYUNIONNAME.Algid

The algorithm identifier associated with this OID information.

This member applies for the following values of dwGroupId:

  • CRYPT_HASH_ALG_OID_GROUP_ID
  • CRYPT_ENCRYPT_ALG_OID_GROUP_ID
  • CRYPT_PUBKEY_ALG_OID_GROUP_ID
  • CRYPT_SIGN_ALG_OID_GROUP_ID

DUMMYUNIONNAME.dwLength

This member is not implemented. It is always set to zero.

ExtraInfo

Extra information used to find or register OID information. This member applies for the following values of dwGroupId:

  • CRYPT_PUBKEY_ALG_OID_GROUP_ID
  • CRYPT_SIGN_ALG_OID_GROUP_ID
  • CRYPT_RDN_ATTR_OID_GROUP_ID
The OIDs in the CRYPT_ENCRYPT_ALG_OID_GROUP_ID OID group have a bit length set for the AES algorithms in the DWORD[0] member of the ExtraInfo member.

The OIDs in the CRYPT_PUBKEY_ALG_OID_GROUP_ID group have a flag set in the DWORD[0] member of the ExtraInfo member.

The OIDs in the ECC curve name public keys, for example, szOID_ECC_CURVE_P256 ("1.2.840.10045.3.1.7"), have a flag set in the DWORD[0] member, a BCRYPT_ECCKEY_BLOB dwMagic field value set in the DWORD[1] member, and a bit length where the BCRYPT_ECCKEY_BLOB cbKey value equals dwBitLength / 8 + ((dwBitLength % 8) ? 1 : 0) set in the DWORD[2] member of the ExtraInfo member.

The OIDs in the CRYPT_SIGN_ALG_OID_GROUP_ID group have a public key algorithm identifier set in the DWORD[0] member, a flag set in the DWORD[1] member, and an optional provider type set in the DWORD[2] member of the ExtraInfo member.

The OIDs in the CRYPT_RDN_ATTR_OID_GROUP_ID group have a null-terminated list of acceptable RDN attribute value types set in an array of DWORD values in the ExtraInfo member. An omitted list implies an array of values where the first value in the array is CERT_RDN_PRINTABLE_STRING, the second value in the array is CERT_RDN_UNICODE_STRING, and the third value in the array is zero.

The following values are used for the flags in the ExtraInfo member.

Value Meaning
CRYPT_OID_INHIBIT_SIGNATURE_FORMAT_FLAG
 This flag is no longer used.

Stop the reformatting of the signature before the CryptVerifySignature function is called or after the CryptSignHash function is called.
CRYPT_OID_NO_NULL_ALGORITHM_PARA_FLAG
 Omit NULL parameters when encoding.
CRYPT_OID_PUBKEY_ENCRYPT_ONLY_FLAG
 The public key is only used for encryption.
CRYPT_OID_PUBKEY_SIGN_ONLY_FLAG
 The public key is only used for signatures.
CRYPT_OID_USE_PUBKEY_PARA_FOR_PKCS7_FLAG
 This flag is no longer used.

Include the parameters of the public key algorithm in the digestEncryptionAlgorithm parameters for the PKCS #7 message.

pwszCNGAlgid

The algorithm identifier string passed to the CNG functions (the BCrypt* and NCrypt* functions that are defined in Bcrypt.h and Ncrypt.h). CNG functions use algorithm identifier strings, such as L"SHA1", instead of the ALG_ID data type constants, such as CALG_SHA1.Windows Server 2003 and Windows XP:  This member is not available.

Note  The pwszCNGAlgid member is only available if you include the following statement in your code.
 
#define CRYPT_OID_INFO_HAS_EXTRA_FIELDS

This member applies for the following values of dwGroupId:

  • CRYPT_HASH_ALG_OID_GROUP_ID
  • CRYPT_ENCRYPT_ALG_OID_GROUP_ID
  • CRYPT_PUBKEY_ALG_OID_GROUP_ID
  • CRYPT_SIGN_ALG_OID_GROUP_ID
Set the pwszCNGAlgid member to the empty string, L"", for the other values of dwGroupId.

The pwszCNGAlgid member can also be set to a string value that is not passed directly to the CNG functions. The following table lists these values and their meanings.

Value Meaning
CRYPT_OID_INFO_ECC_PARAMETERS_ALGORITHM
 The ECC curve algorithm is obtained from the encoded parameters of the OID algorithm.
CRYPT_OID_INFO_ECC_WRAP_PARAMETERS_ALGORITHM
 The key wrap algorithm is obtained from the encoded parameters of the OID algorithm.
CRYPT_OID_INFO_HASH_PARAMETERS_ALGORITHM
 The hash algorithm is obtained from the encoded parameters of the OID algorithm.
CRYPT_OID_INFO_MGF1_PARAMETERS_ALGORITHM
 The PKCS #1 v2.1 mask generation hash algorithm is obtained from the encoded parameters of the OID algorithm.
CRYPT_OID_INFO_NO_SIGN_ALGORITHM
 A public key algorithm that indicates the signature value is an unsigned hash.
CRYPT_OID_INFO_OAEP_PARAMETERS_ALGORITHM
 The RSAES-OAEP padding hash algorithm is obtained from the encoded parameters of the OID algorithm.

pwszCNGExtraAlgid

An extra algorithm string, other than the string in the pwszCNGAlgid member, that can be passed to the CNG functions (the BCrypt* and NCrypt* functions that are defined in Bcrypt.h and Ncrypt.h).

Windows Server 2003 and Windows XP:  This member is not available.

Note  This member is only available if you include the following statement in your code.
 
#define CRYPT_OID_INFO_HAS_EXTRA_FIELDS

For the signature algorithms (CRYPT_SIGN_ALG_OID_GROUP_ID), this member is the public key algorithm string to pass to the CNG functions.

For ECC signatures, this member is the special CRYPT_OID_INFO_ECC_PARAMETERS_ALGORITHM string value.

For unsigned signatures, this member is the special CRYPT_OID_INFO_NO_SIGN_ALGORITHM string value.

For ECC curve name public keys, for example, szOID_ECC_CURVE_P256 ("1.2.840.10045.3.1.7"), this is the special CRYPT_OID_INFO_ECC_PARAMETERS_ALGORITHM string value.

For the other values of dwGroupId, set the pwszCNGExtraAlgid member to the empty string, L"".

Requirements

Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Header wincrypt.h

See also

CryptFindOIDInfo

CryptRegisterOIDInfo

CryptUnregisterOIDInfo