AAL2VerifySignature

Function prototype

aat_int32 AAL2VerifySignature (
                               TDigipassBlob*   DPData,
                               TKernelParms*    CallParms,
                               aat_ascii*       Signature,
                               aat_ascii        SignedDataFields [8][20],
                               aat_int32        FieldCount,
                               aat_int32        DeferredSignatureData);

Description

This function is called by passing the necessary data to perform signature validation and integrity control, based on the signature code generated by the user's Digipass authenticator, and up to eight signed data fields on which authentication and integrity control are performed. The exact number of valid data fields is given in FieldCount.

You may also need to use AAL2VerifySignatureEx, which provides you with a signature confirmation code.

With Digipass 110, AAL2VerifySignatureEs must be used instead of AAL2VerifySignature.

This function is used to perform signature validation on the standard signature process involving up to eight signed data fields.

This function cannot be used to perform signature validation of a Secure Channel transaction (signature based on a Secure Channel request message). For signature validation of a Secure Channel transaction, AAL2VerifyMessageSignature must be used instead of AAL2VerifySignature.

OnLineSG

The OnlineSG kernel parameter determines in which mode the signature is used.

• OnlineSG = 0 (default): The signature is verified in offline mode.

  Choose this mode exclusively for fax banking applications (big time step, signature not presented in sequence).

  In offline mode, the Digipass authenticator is not synchronized with the authenticator application BLOB. LastTimeUsed, LastTimeShift are not updated. EventValue will be updated only if the Digipass event value used to generate the signature is greater than the event value stored in the authenticator application BLOB.

  The Digipass time (time of Digipass at the generation of the initial online signature) can be passed to the offline signature validation function using the DeferredSignatureData parameter (with 0, the current time is used). The Digipass time can be read after an online AAL2VerifySignature call using AAL2GetTokenProperty with the property LAST_TIME_USED | INT_VALUE. The INT_VALUE flag allows obtaining the LastTimeUsed value as integer value enclosed in the Value parameter of the function.

  For more information, refer to AAL2GetTokenProperty and AAL2GetTokenInfoEx.

• OnlineSG = 1: The signature is verified in online mode.

  Choose this mode for web applications (small time step, signature presented in sequence). Several signatures are allowed within the same Digipass TimeStep (except identical successive ones).

• OnlineSG = 2: The signature is verified in online mode.

  Identical to OnlineSG = 1, except that only one signature per Digipass TimeStep is allowed.

• OnlineSG = 3: The signature is verified in offline mode.

In offline mode, the Digipass authenticator is not synchronized with the authenticator application BLOB. LastTimeUsed, LastTimeShift are not updated. EventValue will be updated only if the Digipass event value used to generate the signature is greater than the event value stored in the authenticator application BLOB.

The event counter (Digipass counter at the generation of the initial online signature) must be passed to the offline signature validation function using the DeferredSignatureData parameter. The Digipass counter can be read after an online AAL2VerifySignature call using AAL2GetTokenProperty with the property EVENT_VALUE | INT_VALUE. The INT_VALUE flag allows obtaining the EventValue value as integer value enclosed in the Value parameter of the function.

Score-based Digipass

For Digipass devices that integrate the score-based algorithm, Authentication Suite Server SDK performs a score-based signature validation which allows retrieving the Digipass scoring value. Once Authentication Suite Server SDK has successfully validated the signature, it returns either SUCCESS or SUCCESS with the relevant scoring warning code. See the list of return codes in Table: Return codes (AAL2VerifySignature) for more details.

Parameters

Return codes

* Specific score-based authentication codes; For more information, refer to  Score-based Digipass.