The VDS_ISCSI_SHARED_SECRET structure defines the Challenge-Handshake Authentication Protocol (CHAP), as specified in [MS-CHAP], shared secret for an iSCSI initiator.

 typedef struct _VDS_ISCSI_SHARED_SECRET {
   [size_is(ulSharedSecretSize)] unsigned char* pSharedSecret;
   unsigned long ulSharedSecretSize;

pSharedSecret: A pointer to an array of bytes that contains the secret.

ulSharedSecretSize: The number of bytes contained in the array that pSharedSecret references. Bytes MUST be at least 12 and less than or equal to 16.<33> If a shared secret of size less than 12 bytes is used, the server does not return an error. However, the operation will not complete.