CRYPT_BIT_BLOB structure (wincrypt.h)

The CRYPT_BIT_BLOB structure contains a set of bits represented by an array of bytes.

Syntax

typedef struct _CRYPT_BIT_BLOB {
  DWORD cbData;
  BYTE  *pbData;
  DWORD cUnusedBits;
} CRYPT_BIT_BLOB, *PCRYPT_BIT_BLOB;

Members

cbData

The number of bytes in the pbData array.

pbData

A pointer to an array of bytes that represents the bits.

cUnusedBits

The number of unused bits in the last byte of the array. The unused bits are always the least significant bits in the last byte of the array.

Remarks

Because the smallest chunk of memory that can normally be allocated is a byte, the CRYPT_BIT_BLOB structure allows the last byte in the array to contain zero to seven unused bits. The number of unused bits in the array is contained in the cUnusedBits member of this structure. The number of meaningful bits in the pbData member is calculated with the formula ((cbData × 8) –cUnusedBits). For example, if you need to represent 10 bits, you would allocate an array of 2 bytes and set cUnusedBits to 6. If you view the array as contiguous bits from left to right, the left 10 bits would be meaningful, and the right 6 bits would be unused.

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

CERT_BASIC_CONSTRAINTS_INFO

CERT_INFO

CERT_KEY_ATTRIBUTES_INFO

CERT_KEY_USAGE_RESTRICTION_INFO

CERT_PUBLIC_KEY_INFO

CERT_SIGNED_CONTENT_INFO