CryptStringToBinaryA function (wincrypt.h)

The CryptStringToBinary function converts a formatted string into an array of bytes.

Syntax

BOOL CryptStringToBinaryA(
  [in]      LPCSTR pszString,
  [in]      DWORD  cchString,
  [in]      DWORD  dwFlags,
  [in]      BYTE   *pbBinary,
  [in, out] DWORD  *pcbBinary,
  [out]     DWORD  *pdwSkip,
  [out]     DWORD  *pdwFlags
);

Parameters

[in] pszString

A pointer to a string that contains the formatted string to be converted.

[in] cchString

The number of characters of the formatted string to be converted, not including the terminating NULL character. If this parameter is zero, pszString is considered to be a null-terminated string.

[in] dwFlags

Indicates the format of the string to be converted. This can be one of the following values.

[in] pbBinary

A pointer to a buffer that receives the returned sequence of bytes. If this parameter is NULL, the function calculates the length of the buffer needed and returns the size, in bytes, of required memory in the DWORD pointed to by pcbBinary.

[in, out] pcbBinary

A pointer to a DWORD variable that, on entry, contains the size, in bytes, of the pbBinary buffer. After the function returns, this variable contains the number of bytes copied to the buffer. If this value is not large enough to contain all of the data, the function fails and GetLastError returns ERROR_MORE_DATA.

If pbBinary is NULL, the DWORD pointed to by pcbBinary is ignored.

[out] pdwSkip

A pointer to a DWORD value that receives the number of characters skipped to reach the beginning of the -----BEGIN ...----- header. If no header is present, then the DWORD is set to zero. This parameter is optional and can be NULL if it is not needed.

[out] pdwFlags

A pointer to a DWORD value that receives the flags actually used in the conversion. These are the same flags used for the dwFlags parameter. In many cases, these will be the same flags that were passed in the dwFlags parameter. If dwFlags contains one of the following flags, this value will receive a flag that indicates the actual format of the string. This parameter is optional and can be NULL if it is not needed.

Return value

If the function succeeds, the return value is nonzero (TRUE).

If the function fails, the return value is zero (FALSE).

Remarks

The CRYPT_STRING_BASE64HEADER, CRYPT_STRING_BASE64REQUESTHEADER, and CRYPT_STRING_BASE64X509CRLHEADER flags are all treated identically by this function: They attempt to parse the first block of base64-encoded data between lines of the form -----BEGIN ...----- and -----END ...-----. The ... portions are ignored, and they need not match. If parsing is successful, the value passed in the dwFlags parameter is returned in the DWORD pointed to by the pdwFlags parameter. Note that a value of CRYPT_STRING_BASE64REQUESTHEADER or CRYPT_STRING_BASE64X509CRLHEADER does not mean that a request header or X.509 certificate revocation list (CRL) was found.

Requirements

See also

CryptBinaryToString