IPSEC_OFFLOAD_V2_ALGORITHM_INFO structure (ndis.h)

Article
04/01/2021

[The IPsec Task Offload feature is deprecated and should not be used.]

The IPSEC_OFFLOAD_V2_ALGORITHM_INFO structure specifies an algorithm that is used for a security association (SA).

Syntax

typedef struct _IPSEC_OFFLOAD_V2_ALGORITHM_INFO {
  ULONG Identifier;
  ULONG KeyLength;
  ULONG KeyOffsetBytes;
  ULONG AdditionalInfo;
} IPSEC_OFFLOAD_V2_ALGORITHM_INFO, *PIPSEC_OFFLOAD_V2_ALGORITHM_INFO;

Members

Identifier

The encryption or authentication algorithm that is used for the SA.

If the algorithm is an encryption algorithm, Identifier can be any of the following values:

IPSEC_OFFLOAD_V2_ENCRYPTION_NONE

Specifies no confidentiality algorithm. This value is used for null encryption--that is, when a packet is not encrypted but does include ESP authentication information.

IPSEC_OFFLOAD_V2_ENCRYPTION_DES_CBC

Specifies the DES algorithm for encrypting and decrypting ESP payloads.

IPSEC_OFFLOAD_V2_ENCRYPTION_3_DES_CBC

Specifies the triple-DES algorithm for encrypting and decrypting ESP payloads.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_GCM_128

Specifies the AES-GCM 128 algorithm for encrypting and computing a cryptographic checksum or decrypting and validating a cryptographic checksum for an ESP payload. Note that this is a combined mode algorithm.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_GCM_192

Specifies the AES-GCM 192 algorithm for encrypting and computing a cryptographic checksum or decrypting and validating a cryptographic checksum for an ESP payload. Note that this is a combined mode algorithm.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_GCM_256

Specifies the AES-GCM 256 algorithm for encrypting and computing a cryptographic checksum or decrypting and validating a cryptographic checksum for an ESP payload. Note that this is a combined mode algorithm.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_CBC_128

Specifies the Advanced Encryption Standard - cipher-block chaining mode (AES-CBC) 128 algorithm for encrypting and decrypting ESP payloads.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_CBC_192

Specifies the AES-CBC 192 algorithm for encrypting and decrypting ESP payloads.

IPSEC_OFFLOAD_V2_ENCRYPTION_AES_CBC_256

Specifies the AES-CBC 256 algorithm for encrypting and decrypting ESP payloads.

If the algorithm is an authentication algorithm, Identifier can be one of the following values:

IPSEC_OFFLOAD_V2_AUTHENTICATION_MD5

Specifies the keyed message digest 5 (MD5) algorithm for computing or validating a cryptographic checksum.

IPSEC_OFFLOAD_V2_AUTHENTICATION_SHA_1

Specifies the secure hash algorithm (SHA) 1 algorithm for computing or validating a cryptographic checksum.

IPSEC_OFFLOAD_V2_AUTHENTICATION_SHA_256

Specifies the SHA 256 algorithm for computing or validating a cryptographic checksum.

IPSEC_OFFLOAD_V2_AUTHENTICATION_AES_GCM_128

Specifies the Advanced Encryption Standard - Galois/Counter Mode (AES- GMAC) 128 algorithm for computing or validating a cryptographic checksum.

IPSEC_OFFLOAD_V2_AUTHENTICATION_AES_GCM_192

Specifies the AES- GMAC 192 algorithm for computing or validating a cryptographic checksum.

IPSEC_OFFLOAD_V2_AUTHENTICATION_AES_GCM_256

Specifies the AES- GMAC 256 algorithm for computing or validating a cryptographic checksum.

KeyLength

The length, in bytes, of the key for the algorithm. The key is contained in the array at the KeyData member in the IPSEC_OFFLOAD_V2_ADD_SA structure.

KeyLength indicates the length of the cryptographic algorithm, starting at the offset that is specified in KeyOffsetBytes .

If both algorithms ( AuthenticationAlgorithm and EncryptionAlgorithm ) are specified in IPSEC_OFFLOAD_V2_SECURITY_ASSOCIATION, the keys are concatenated. The respective keys start at the offset that is specified in KeyOffsetBytes .

KeyOffsetBytes

The offset, in bytes, into in the array at the KeyData member in the IPSEC_OFFLOAD_V2_ADD_SA structure.

AdditionalInfo

Additional information that should be interpreted differently based on the algorithm. For AES-GCM,
AdditionalInfo contains the ICV length.

Remarks

The IPSEC_OFFLOAD_V2_ALGORITHM_INFO structure specifies algorithm information in the EncryptionAlgorithm and AuthenticationAlgorithm members of the IPSEC_OFFLOAD_V2_SECURITY_ASSOCIATION structure.

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.1 and later.
Header	ndis.h (include Ndis.h)