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Key Storage Property Identifiers

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The following values are used to identify a key storage property.

Identifiers

NCRYPT_ALGORITHM_GROUP_PROPERTY

L"Algorithm Group"

A null-terminated Unicode string that contains the name of the object's algorithm group. This property only applies to keys. The following identifiers are returned by the Microsoft key storage provider.

Identifier Value Description
NCRYPT_RSA_ALGORITHM_GROUP "RSA" The RSA algorithm group.
NCRYPT_DH_ALGORITHM_GROUP "DH" The Diffie-Hellman algorithm group.
NCRYPT_DSA_ALGORITHM_GROUP "DSA" The DSA algorithm group.
NCRYPT_ECDSA_ALGORITHM_GROUP "ECDSA" The elliptic curve DSA algorithm group.
NCRYPT_ECDH_ALGORITHM_GROUP "ECDH" The elliptic curve Diffie-Hellman algorithm group.

NCRYPT_ALGORITHM_PROPERTY

L"Algorithm Name"

A null-terminated Unicode string that contains the name of the object's algorithm. This can be one of the predefined CNG Algorithm Identifiers or another registered algorithm identifier. This property only applies to keys.

NCRYPT_ASSOCIATED_ECDH_KEY

L"SmartCardAssociatedECDHKey"

An LPWSTR value that indicates the container name of the Elliptic Curve Diffie-Hellman (ECDH) key to use during logon for a given handle to an Elliptic Curve Digital Signature Algorithm (ECDSA) key. If there are no ECDH keys on the card, the key storage provider (KSP) returns NTE_NOT_FOUND. This property applies to ECDSA keys for logon with smart cards. The property is supported by the Microsoft Smart Card key storage provider and not by the Microsoft Software key storage provider.

Windows Server 2008 and Windows Vista: This value is not supported.

NCRYPT_BLOCK_LENGTH_PROPERTY

L"Block Length"

A DWORD that contains the length, in bytes, of the encryption block. This property only applies to keys that support encryption.

NCRYPT_CERTIFICATE_PROPERTY

L"SmartCardKeyCertificate"

A BLOB that contains an X.509 certificate that is associated with the key.

Windows Server 2008 R2, Windows 7, Windows Server 2008 and Windows Vista: A BLOB that contains the smart card key certificate. This property is not supported by the Microsoft Software Key Storage Provider.

NCRYPT_DH_PARAMETERS_PROPERTY

L"DHParameters"

Specifies parameters to use with a Diffie-Hellman key. This data type is a pointer to a BCRYPT_DH_PARAMETER_HEADER structure. This property can only be set and must be set for the key before the key is completed.

NCRYPT_EXPORT_POLICY_PROPERTY

L"Export Policy"

A DWORD that contains a set of flags that specify the export policy for a persisted key. This property only applies to keys. This can contain zero or a combination of one or more of the following values.

Identifier Value Description
NCRYPT_ALLOW_EXPORT_FLAG 0x00000001 The private key can be exported.
NCRYPT_ALLOW_PLAINTEXT_EXPORT_FLAG 0x00000002 The private key can be exported in plaintext form.
NCRYPT_ALLOW_ARCHIVING_FLAG 0x00000004 The private key can be exported once for archiving purposes. This flag only applies to the original key handle on which it is set. This policy can only be applied to the original key handle. After the key handle has been closed, the key can no longer be exported for archiving purposes.
NCRYPT_ALLOW_PLAINTEXT_ARCHIVING_FLAG 0x00000008 The private key can be exported once in plaintext form for archiving purposes. This flag only applies to the original key handle on which it is set. This policy can only be applied to the original key handle. After the key handle has been closed, the key can no longer be exported for archiving purposes.

NCRYPT_IMPL_TYPE_PROPERTY

L"Impl Type"

A DWORD that contains a set of flags that define implementation details of the provider. This property only applies to key storage providers. This can contain zero or a combination of one or more of the following values.

Identifier Value Description
NCRYPT_IMPL_HARDWARE_FLAG 0x00000001 The provider is hardware based.
NCRYPT_IMPL_SOFTWARE_FLAG 0x00000002 The provider is software based.
NCRYPT_IMPL_REMOVABLE_FLAG 0x00000008 The provider is removable.
NCRYPT_IMPL_HARDWARE_RNG_FLAG 0x00000010 The provider is a hardware based random number generator.

NCRYPT_KEY_TYPE_PROPERTY

L"Key Type"

A DWORD that contains a set of flags that define the key type. This property only applies to keys. This can contain zero or the following value.

Identifier Value Description
NCRYPT_MACHINE_KEY_FLAG 0x00000020 The key applies to the local computer. If this flag is not present, the key applies to the current user.

NCRYPT_KEY_USAGE_PROPERTY

L"Key Usage"

A DWORD that contains a set of flags that define the usage details for a key. This property only applies to keys. This can contain zero or a combination of one or more of the following values.

Identifier Value Description
NCRYPT_ALLOW_DECRYPT_FLAG 0x00000001 The key can be used for decryption.
NCRYPT_ALLOW_SIGNING_FLAG 0x00000002 The key can be used for signing.
NCRYPT_ALLOW_KEY_AGREEMENT_FLAG 0x00000004 The key can be used for secret agreement encryption.
NCRYPT_ALLOW_KEY_ATTESTATION_FLAG 0x00000010 Indicates the key is a key with attestation.
NCRYPT_ALLOW_ALL_USAGES 0x00ffffff The key can be used for any purpose.

NCRYPT_LAST_MODIFIED_PROPERTY

L"Modified"

Indicates when the key was last modified. This data type is a pointer to a FILETIME structure. This property only applies to persisted keys.

NCRYPT_LENGTH_PROPERTY

L"Length"

A DWORD that contains the length, in bits, of the key. This property only applies to keys.

NCRYPT_LENGTHS_PROPERTY

L"Lengths"

Indicates the key sizes that are supported by the key. This data type is a pointer to an NCRYPT_SUPPORTED_LENGTHS structure that contains this information. This property only applies to keys.

NCRYPT_MAX_NAME_LENGTH_PROPERTY

L"Max Name Length"

A DWORD that contains the maximum length, in characters, of the name of a persistent key. This property only applies to a provider.

This property is primarily intended to be used by key storage providers that store their keys on a device that has a limited amount of available memory, such as a smart card.

NCRYPT_NAME_PROPERTY

L"Name"

A pointer to a null-terminated Unicode string that contains the name of the object.

NCRYPT_PIN_PROMPT_PROPERTY

L"SmartCardPinPrompt"

This value is not supported.

NCRYPT_PIN_PROPERTY

L"SmartCardPin"

A pointer to a null-terminated Unicode string that contains the PIN. The PIN is used for a smart card key or the password for a password-protected key stored in a software-based KSP. This property can only be set. Microsoft KSPs will cache this value so that the user is only prompted once per process.

NCRYPT_PROVIDER_HANDLE_PROPERTY

L"Provider Handle"

An NCRYPT_PROV_HANDLE that contains the handle of the CNG key storage provider. When you are finished using the handle, you must call NCryptFreeObject to release it.

NCRYPT_READER_PROPERTY

L"SmartCardReader"

A pointer to a null-terminated Unicode string that contains the name of the smart card reader. This property can only be set.

NCRYPT_ROOT_CERTSTORE_PROPERTY

L"SmartcardRootCertStore"

An HCERTSTORE that represents the smart card root certificate store.

NCRYPT_SCARD_PIN_ID

L"SmartCardPinId"

A pointer to the PIN_ID value associated with a given cryptographic key on a smart card. This is a read-only property. The PIN_ID data type is defined in Cardmod.h.

Windows Server 2008 and Windows Vista: This value is not supported.

Note

The Cardmod.h C header file provides additional information that is relevant to this API. This file contains the function prototypes and structures that Microsoft smart card minidriver API specifies. This API is available through the Microsoft Cryptographic Provider Development Kit (CPDK).

NCRYPT_SCARD_PIN_INFO

L"SmartCardPinInfo"

A pointer to PIN_INFO structure of the PIN associated with a given cryptographic key on the smart card. The caller provides the key handle. This property is a read-only property. The PIN_INFO structure is defined in Cardmod.h.

Windows Server 2008 and Windows Vista: This value is not supported.

NCRYPT_SECURE_PIN_PROPERTY

L"SmartCardSecurePin"

A pointer to a null-terminated Unicode string that contains the smart card session PIN. This property can only be set.

Windows Vista: This property is not supported.

NCRYPT_SECURITY_DESCR_PROPERTY

L"Security Descr"

A pointer to a SECURITY_DESCRIPTOR structure that contains access control information for the key. This property only applies to persistent keys. The dwFlags parameter of the NCryptGetProperty or NCryptSetProperty function identifies the part of the security descriptor to get or set.

NCRYPT_SECURITY_DESCR_SUPPORT_PROPERTY

L"Security Descr Support"

Indicates whether the provider supports security descriptors for keys. This property is a DWORD that contains 1 if the provider supports security descriptors for keys. If this property contains any other value, or if the NCryptGetProperty function returns NTE_NOT_SUPPORTED, then the provider does not support security descriptors for keys. This property only applies to providers.

NCRYPT_SMARTCARD_GUID_PROPERTY

L"SmartCardGuid"

A BLOB that contains the identifier of the smart card.

NCRYPT_UI_POLICY_PROPERTY

L"UI Policy"

If used with the NCryptSetProperty or NCryptGetProperty function, this is a pointer to an NCRYPT_UI_POLICY structure that contains the strong key user interface policy for the key. This property only applies to persistent keys. This property can only be set when the key is being generated. Once the NCryptFinalizeKey function has been called for this key, this property becomes read-only.

A key storage provider can receive this parameter through an NCryptSetPropertyFn callback function. The parameter value is an NCRYPT_UI_POLICY_BLOB structure that contains the same information. Similarly, when an application makes a request through NCryptSetPropertyFn to the provider to return this property, the provider is expected to return an NCRYPT_UI_POLICY_BLOB structure.

NCRYPT_UNIQUE_NAME_PROPERTY

L"Unique Name"

A pointer to a null-terminated Unicode string that contains the unique name of the object. This is an alternate name that can be used when accessing the key. This property is used when it is thought that the key name originally passed to NCryptCreatePersistedKey is not unique enough to reliably identify the persisted key. The Microsoft key storage provider will return the file name of the key as this property.

NCRYPT_USE_CONTEXT_PROPERTY

L"Use Context"

A pointer to a null-terminated Unicode string that describes the context of the operation. This property is not persistent and can be set on either a provider or a key. A key does not have access to the NCRYPT_USE_CONTEXT_PROPERTY property of the provider because the property is specific only to the handle it is set for.

An example where this property would be used in the context of a provider is a key storage provider that needs to prompt the user during a call to NCryptOpenKey (for example, "Insert your smart card in the reader."). Because the key handle is not available until after NCryptOpenKey returns, the application should set this property on the provider handle prior to calling NCryptOpenKey.

An example where this property would be used in the context of a key handle is a key storage provider that needs to prompt the user during an operation using the key (for example, "This application needs to use this key to sign a document."). The provider could then relay this context information to the user in any user interface shown during the operation.

NCRYPT_USE_COUNT_ENABLED_PROPERTY

L"Enabled Use Count"

Indicates whether the provider supports usage counting for keys. This property is a DWORD that contains 1 if the provider supports usage counting for keys. If this property contains any other value, or if the NCryptGetProperty function returns NTE_NOT_SUPPORTED, then the provider does not support usage counting for keys. This property only applies to providers.

NCRYPT_USE_COUNT_PROPERTY

L"Use Count"

A ULARGE_INTEGER variable that contains the number of operations that the specified private key has performed. This property is optional and may not be supported by all providers. Providers that support this property on keys should also support the NCRYPT_USE_COUNT_ENABLED_PROPERTY property on the provider handle. The Microsoft key storage provider does not support this property. This property only applies to persistent keys.

NCRYPT_USER_CERTSTORE_PROPERTY

L"SmartCardUserCertStore"

An HCERTSTORE that represents the smart card user certificate store.

NCRYPT_VBS_ROOT_PUB_PROPERTY

L"VBS_ROOT_PUB"

A new property of the MS_KEY_STORAGE_PROVIDER provider. This property enables the retrieval of the public part of the root Signing Key (IDKS) of Virtualization Based Security (VBS).

NCRYPT_VERSION_PROPERTY

L"Version"

A DWORD that contains the software version of the provider. The high word contains the major version and the low word contains the minor version. For example, 0x00030033 = 3.51. This property only applies to providers.

NCRYPT_WINDOW_HANDLE_PROPERTY

L"HWND Handle"

A pointer to the window handle (HWND) to be used as the parent of any user interface that is displayed.

Because undesirable behavior can happen when a user interface is shown by using a NULL window handle for the parent, we strongly recommend that a key storage provider not display a user interface unless this property is set.

The following values are used to define limits of property data.

Constant Value Description
NCRYPT_MAX_PROPERTY_DATA 0x100000 Specifies the maximum size of a property value, in bytes.
NCRYPT_MAX_PROPERTY_NAME 64 Specifies the maximum size of a property name, in characters.

Requirements

Requirement Value
Minimum supported client Windows Vista [desktop apps only]
Minimum supported server Windows Server 2008 [desktop apps only]
Header Ncrypt.h

See also