Keyfiles

Keyfile is a file whose content is combined with a password (for information on the method used to combine a keyfile with password, see the section Keyfiles in the chapter Technical Details). Until the correct keyfile is provided, no volume that uses the keyfile can be mounted.

You do not have to use keyfiles. However, using keyfiles has some advantages:

• May improve protection against brute force attacks (significant particularly if the volume password is not very strong).
• Allows the use of security tokens and smart cards (see below).
• Allows multiple users to mount a single volume using different user passwords or PINs. Just give each user a security token or smart card containing the same VeraCrypt keyfile and let them choose their personal password or PIN that will protect their security token or smart card.
• Allows managing multi-user shared access (all keyfile holders must present their keyfiles before a volume can be mounted).

Any kind of file (for example, .txt, .exe, mp3**, .avi) can be used as a VeraCrypt keyfile (however, we recommend that you prefer compressed files, such as .mp3, .jpg, .zip, etc).

Note that VeraCrypt never modifies the keyfile contents. You can select more than one keyfile; the order does not matter. You can also let VeraCrypt generate a file with random content and use it as a keyfile. To do so, select Tools > Keyfile Generator.

Note: Keyfiles are currently not supported for system encryption.

WARNING: If you lose a keyfile or if any bit of its first 1024 kilobytes changes, it will be impossible to mount volumes that use the keyfile!

WARNING: If password caching is enabled, the password cache also contains the processed contents of keyfiles used to successfully mount a volume. Then it is possible to remount the volume even if the keyfile is not available/accessible. To prevent this, click 'Wipe Cache' or disable password caching (for more information, please see the subsection 'Settings -> Preferences', item 'Cache passwords in driver memory' in the section Program Menu).

See also the section Choosing Passwords and Keyfiles in the chapter Security Requirements and Precautions.

 

Keyfiles Dialog Window

If you want to use keyfiles (i.e. "apply" them) when creating or mounting volumes, or changing passwords, look for the 'Use keyfiles' option and the Keyfiles button below a password input field.

These control elements appear in various dialog windows and always have the same functions. Check the Use keyfiles option and click Keyfiles. The keyfile dialog window should appear where you can specify keyfiles (to do so, click Add Files or Add Token Files) or keyfile search paths (click Add Path).

 

Security Tokens and Smart Cards

VeraCrypt can directly use keyfiles stored on a security token or smart card that complies with the PKCS #11 (2.0 or later) standard [23] and that allows the user to store a file (data object) on the token/card. To use such files as VeraCrypt keyfiles, click Add Token Files (in the keyfile dialog window).

Access to a keyfile stored on a security token or smart card is typically protected by PIN codes, which can be entered either using a hardware PIN pad or via the VeraCrypt GUI. It can also be protected by other means, such as fingerprint readers.

In order to allow VeraCrypt to access a security token or smart card, you need to install a PKCS #11 (2.0 or later) software library for the token or smart card first. Such a library may be supplied with the device or it may be available for download from the website of the vendor or other third parties.

If your security token or smart card does not contain any file (data object) that you could use as a VeraCrypt keyfile, you can use VeraCrypt to import any file to the token or smart card (if it is supported by the device). To do so, follow these steps:

1. In the keyfile dialog window, click Add Token Files.
2. If the token or smart card is protected by a PIN, password, or other means (such as a fingerprint reader), authenticate yourself (for example, by entering the PIN using a hardware PIN pad).
3. The 'Security Token Keyfile' dialog window should appear. In it, click Import Keyfile to Token and then select the file you want to import to the token or smart card.

Note that you can import for example 512-bit keyfiles with random content generated by VeraCrypt (see Tools > Keyfile Generator below).

To close all opened security token sessions, either select Tools > Close All Security Token Sessions or define and use a hotkey combination (Settings > Hot Keys > Close All Security Token Sessions).

 

Keyfile Search Path

By adding a folder in the keyfile dialog window (click Add Path), you specify a keyfile search path. All files found in the keyfile search path* will be used as keyfiles except files that have the Hidden file attribute set.

Important: Note that folders (and files they contain) and hidden files found in a keyfile search path are ignored.

Keyfile search paths are especially useful if you, for example, store keyfiles on a USB memory stick that you carry with you. You can set the drive letter of the USB memory stick as a default keyfile search path. To do so, select Settings -> Default Keyfiles. Then click
Add Path, browse to the drive letter assigned to the USB memory stick, and click OK. Now each time you mount a volume (and if the option Use keyfiles is checked in the password dialog window), VeraCrypt will scan the path and use all files that it finds on the USB memory stick as keyfiles.

WARNING: When you add a folder (as opposed to a file) to the list of keyfiles, only the path is remembered, not the filenames! This means e.g. that if you create a new file in the folder or if you copy an additional file to the folder, then all volumes that used keyfiles from the folder will be impossible to mount (until you remove the newly added file from the folder).

 

Empty Password & Keyfile

When a keyfile is used, the password may be empty, so the keyfile may become the only item necessary to mount the volume (which we do not recommend). If default keyfiles are set and enabled when mounting a volume, then before prompting for a password, VeraCrypt first automatically attempts to mount using an empty password plus default keyfiles (however, this does not apply to the 'Auto-Mount Devices' function). If you need to set Mount Options (e.g., mount as read-only, protect hidden volume etc.) for a volume being mounted this way, hold down the Control (Ctrl) key while clicking Mount (or select Mount with Options from the Volumes menu). This will open the Mount Options dialog.

 

Quick Selection

Keyfiles and keyfile search paths can be quickly selected in the following ways:

• Right-click the Keyfiles button in the password entry dialog window and select one of the menu items.
• Drag the corresponding file/folder icons to the keyfile dialog window or to the password entry dialog.

 

Volumes -> Add/Remove Keyfiles to/from Volume

This function allows you to re-encrypt a volume header with a header encryption key derived from any number of keyfiles (with or without a password), or no keyfiles at all. Thus, a volume which is possible to mount using only a password can be converted to a volume that require keyfiles (in addition to the password) in order to be possible to mount. Note that the volume header contains the master encryption key with which the volume is encrypted. Therefore, the data stored on the volume will not be lost after you use this function.

This function can also be used to change/set volume keyfiles (i.e., to remove some or all keyfiles, and to apply new ones).

Remark: This function is internally equal to the Password Change function.

When VeraCrypt re-encrypts a volume header, the original volume header is first overwritten 256 times with random data to prevent adversaries from using techniques such as magnetic force microscopy or magnetic force scanning tunneling microscopy [17] to recover the overwritten header (however, see also the chapter Security Requirements and Precautions).

 

Volumes -> Remove All Keyfiles from Volume

This function allows you to re-encrypt a volume header with a header encryption key derived from a password and no keyfiles (so that it can be mounted using only a password, without any keyfiles). Note that the volume header contains the master encryption key with which the volume is encrypted. Therefore, the data stored on the volume will not be lost after you use this function.

Remark: This function is internally equal to the Password Change function.

When VeraCrypt re-encrypts a volume header, the original volume header is first overwritten 256 times with random data to prevent adversaries from using techniques such as magnetic force microscopy or magnetic force scanning tunneling microscopy [17] to recover the overwritten header (however, see also the chapter Security Requirements and Precautions).

 

Tools > Keyfile Generator

You can use this function to generate a file or more with random content, which you can use as a keyfile(s) (recommended). This function uses the VeraCrypt Random Number Generator. Note that, by default, only one key file is generated and the resulting file size is 64 bytes (i.e., 512 bits), which is also the maximum possible VeraCrypt password length. It is also possible to generate multiple files and specify their size (either a fixed value for all of them or let VeraCrypt choose file sizes randomly). In all cases, the file size must be comprised between 64 bytes and 1048576 bytes (which is equal to 1MB, the maximum number of a key file bytes processed by VeraCrypt).

Settings -> Default Keyfiles

Use this function to set default keyfiles and/or default keyfile search paths. This function is particularly useful if you, for example, store keyfiles on a USB memory stick that you carry with you. You can add its drive letter to the default keyfile configuration. To do so, click Add Path, browse to the drive letter assigned to the USB memory stick, and click OK. Now each time you mount a volume (and if Use keyfiles is checked in the password dialog), VeraCrypt will scan the path and use all files that it finds there as keyfiles.

WARNING: When you add a folder (as opposed to a file) to your default keyfile list, only the path is remembered, not the filenames! This means e.g. that if you create a new file in the folder or if you copy an additional file to the folder, then all volumes that used keyfiles from the folder will be impossible to mount (until you remove the newly added file from the folder).

IMPORTANT: Note that when you set default keyfiles and/or default keyfile search paths, the filenames and paths are saved unencrypted in the file Default Keyfiles.xml. For more information, please see the chapter VeraCrypt System Files & Application Data.

---

* Found at the time when you are mounting the volume, changing its password, or performing any other operation that involves re-encryption of the volume header.
** However, if you use an MP3 file as a keyfile, you must ensure that no program modifies the ID3 tags within the MP3 file (e.g. song title, name of artist, etc.). Otherwise, it will be impossible to mount volumes that use the keyfile.

/*
  zip_source_win32file.c -- create data source from HANDLE (Win32)
  Copyright (C) 1999-2016 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.
  The authors can be contacted at <libzip@nih.at>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in
  the documentation and/or other materials provided with the
  distribution.
  3. The names of the authors may not be used to endorse or promote
  products derived from this software without specific prior
  written permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include <aclapi.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include "zipint.h"
#include "zipwin32.h"

static zip_int64_t _win32_read_file(void *state, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
static int _win32_create_temp_file(_zip_source_win32_read_file_t *ctx);
static int _zip_filetime_to_time_t(FILETIME ft, time_t *t);
static int _zip_seek_win32_u(void *h, zip_uint64_t offset, int whence, zip_error_t *error);
static int _zip_seek_win32(void *h, zip_int64_t offset, int whence, zip_error_t *error);
static int _zip_win32_error_to_errno(unsigned long win32err);
static int _zip_stat_win32(void *h, zip_stat_t *st, _zip_source_win32_read_file_t *ctx);

ZIP_EXTERN zip_source_t *
zip_source_win32handle(zip_t *za, HANDLE h, zip_uint64_t start, zip_int64_t len) {
    if (za == NULL)
	return NULL;

    return zip_source_win32handle_create(h, start, len, &za->error);
}


ZIP_EXTERN zip_source_t *
zip_source_win32handle_create(HANDLE h, zip_uint64_t start, zip_int64_t length, zip_error_t *error) {
    if (h == INVALID_HANDLE_VALUE || length < -1) {
	zip_error_set(error, ZIP_ER_INVAL, 0);
	return NULL;
    }

    return _zip_source_win32_handle_or_name(NULL, h, start, length, 1, NULL, NULL, error);
}


zip_source_t *
_zip_source_win32_handle_or_name(const void *fname, HANDLE h, zip_uint64_t start, zip_int64_t len, int closep, const zip_stat_t *st, _zip_source_win32_file_ops_t *ops, zip_error_t *error) {
    _zip_source_win32_read_file_t *ctx;
    zip_source_t *zs;

    if (h == INVALID_HANDLE_VALUE && fname == NULL) {
	zip_error_set(error, ZIP_ER_INVAL, 0);
	return NULL;
    }

    if ((ctx = (_zip_source_win32_read_file_t *)malloc(sizeof(_zip_source_win32_read_file_t))) == NULL) {
	zip_error_set(error, ZIP_ER_MEMORY, 0);
	return NULL;
    }

    ctx->fname = NULL;
    if (fname) {
	if ((ctx->fname = ops->op_strdup(fname)) == NULL) {
	    zip_error_set(error, ZIP_ER_MEMORY, 0);
	    free(ctx);
	    return NULL;
	}
    }

    ctx->ops = ops;
    ctx->h = h;
    ctx->start = start;
    ctx->end = (len < 0 ? 0 : start + (zip_uint64_t)len);
    ctx->closep = ctx->fname ? 1 : closep;
    if (st) {
	memcpy(&ctx->st, st, sizeof(ctx->st));
	ctx->st.name = NULL;
	ctx->st.valid &= ~ZIP_STAT_NAME;
    }
    else {
	zip_stat_init(&ctx->st);
    }

    ctx->tmpname = NULL;
    ctx->hout = INVALID_HANDLE_VALUE;

    zip_error_init(&ctx->error);

    ctx->supports = ZIP_SOURCE_SUPPORTS_READABLE | zip_source_make_command_bitmap(ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, -1);
    if (ctx->fname) {
	HANDLE th;

	th = ops->op_open(ctx);
	if (th == INVALID_HANDLE_VALUE || GetFileType(th) == FILE_TYPE_DISK) {
	    ctx->supports = ZIP_SOURCE_SUPPORTS_WRITABLE;
	}
	if (th != INVALID_HANDLE_VALUE) {
	    CloseHandle(th);
	}
    }
    else if (GetFileType(ctx->h) == FILE_TYPE_DISK) {
	ctx->supports = ZIP_SOURCE_SUPPORTS_SEEKABLE;
    }

    if ((zs = zip_source_function_create(_win32_read_file, ctx, error)) == NULL) {
	free(ctx->fname);
	free(ctx);
	return NULL;
    }

    return zs;
}


static zip_int64_t
_win32_read_file(void *state, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
    _zip_source_win32_read_file_t *ctx;
    char *buf;
    zip_uint64_t n;
    DWORD i;

    ctx = (_zip_source_win32_read_file_t *)state;
    buf = (char *)data;

    switch (cmd) {
    case ZIP_SOURCE_BEGIN_WRITE:
	if (ctx->fname == NULL) {
	    zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
	    return -1;
	}
	return _win32_create_temp_file(ctx);

    case ZIP_SOURCE_COMMIT_WRITE: {
	if (!CloseHandle(ctx->hout)) {
	    ctx->hout = INVALID_HANDLE_VALUE;
	    zip_error_set(&ctx->error, ZIP_ER_WRITE, _zip_win32_error_to_errno(GetLastError()));
	}
	ctx->hout = INVALID_HANDLE_VALUE;
	if (ctx->ops->op_rename_temp(ctx) < 0) {
	    zip_error_set(&ctx->error, ZIP_ER_RENAME, _zip_win32_error_to_errno(GetLastError()));
	    return -1;
	}
	free(ctx->tmpname);
	ctx->tmpname = NULL;
	return 0;
    }

    case ZIP_SOURCE_CLOSE:
	if (ctx->fname) {
	    CloseHandle(ctx->h);
	    ctx->h = INVALID_HANDLE_VALUE;
	}
	return 0;

    case ZIP_SOURCE_ERROR:
	return zip_error_to_data(&ctx->error, data, len);

    case ZIP_SOURCE_FREE:
	free(ctx->fname);
	free(ctx->tmpname);
	if (ctx->closep && ctx->h != INVALID_HANDLE_VALUE)
	    CloseHandle(ctx->h);
	free(ctx);
	return 0;

    case ZIP_SOURCE_OPEN:
	if (ctx->fname) {
	    if ((ctx->h = ctx->ops->op_open(ctx)) == INVALID_HANDLE_VALUE) {
		zip_error_set(&ctx->error, ZIP_ER_OPEN, _zip_win32_error_to_errno(GetLastError()));
		return -1;
	    }
	}

	if (ctx->closep && ctx->start > 0) {
	    if (_zip_seek_win32_u(ctx->h, ctx->start, SEEK_SET, &ctx->error) < 0) {
		return -1;
	    }
	}
	ctx->current = ctx->start;
	return 0;

    case ZIP_SOURCE_READ:
	if (ctx->end > 0) {
	    n = ctx->end - ctx->current;
	    if (n > len) {
		n = len;
	    }
	}
	else {
	    n = len;
	}

	if (n > SIZE_MAX)
	    n = SIZE_MAX;

	if (!ctx->closep) {
	    if (_zip_seek_win32_u(ctx->h, ctx->current, SEEK_SET, &ctx->error) < 0) {
		return -1;
	    }
	}

	if (!ReadFile(ctx->h, buf, (DWORD)n, &i, NULL)) {
	    zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(GetLastError()));
	    return -1;
	}
	ctx->current += i;

	return (zip_int64_t)i;

    case ZIP_SOURCE_REMOVE:
	if (ctx->ops->op_remove(ctx->fname) < 0) {
	    zip_error_set(&ctx->error, ZIP_ER_REMOVE, _zip_win32_error_to_errno(GetLastError()));
	    return -1;
	}
	return 0;

    case ZIP_SOURCE_ROLLBACK_WRITE:
	if (ctx->hout) {
	    CloseHandle(ctx->hout);
	    ctx->hout = INVALID_HANDLE_VALUE;
	}
	ctx->ops->op_remove(ctx->tmpname);
	free(ctx->tmpname);
	ctx->tmpname = NULL;
	return 0;

    case ZIP_SOURCE_SEEK: {
	zip_int64_t new_current;
	int need_seek;
	zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);

	if (args == NULL)
	    return -1;

	need_seek = ctx->closep;

	switch (args->whence) {
	case SEEK_SET:
	    new_current = args->offset;
	    break;

	case SEEK_END:
	    if (ctx->end == 0) {
		LARGE_INTEGER zero;
		LARGE_INTEGER new_offset;

		if (_zip_seek_win32(ctx->h, args->offset, SEEK_END, &ctx->error) < 0) {
		    return -1;
		}
		zero.QuadPart = 0;
		if (!SetFilePointerEx(ctx->h, zero, &new_offset, FILE_CURRENT)) {
		    zip_error_set(&ctx->error, ZIP_ER_SEEK, _zip_win32_error_to_errno(GetLastError()));
		    return -1;
		}
		new_current = new_offset.QuadPart;
		need_seek = 0;
	    }
	    else {
		new_current = (zip_int64_t)ctx->end + args->offset;
	    }
	    break;
	case SEEK_CUR:
	    new_current = (zip_int64_t)ctx->current + args->offset;
	    break;

	default:
	    zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
	    return -1;
	}

	if (new_current < 0 || (zip_uint64_t)new_current < ctx->start || (ctx->end != 0 && (zip_uint64_t)new_current > ctx->end)) {
	    zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
	    return -1;
	}

	ctx->current = (zip_uint64_t)new_current;

	if (need_seek) {
	    if (_zip_seek_win32_u(ctx->h, ctx->current, SEEK_SET, &ctx->error) < 0) {
		return -1;
	    }
	}
	return 0;
    }

    case ZIP_SOURCE_SEEK_WRITE: {
	zip_source_args_seek_t *args;

	args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
	if (args == NULL) {
	    return -1;
	}

	if (_zip_seek_win32(ctx->hout, args->offset, args->whence, &ctx->error) < 0) {
	    return -1;
	}
	return 0;
    }

    case ZIP_SOURCE_STAT: {
	if (len < sizeof(ctx->st))
	    return -1;

	if (ctx->st.valid != 0)
	    memcpy(data, &ctx->st, sizeof(ctx->st));
	else {
	    DWORD win32err;
	    zip_stat_t *st;
	    HANDLE h;
	    int success;

	    st = (zip_stat_t *)data;

	    if (ctx->h != INVALID_HANDLE_VALUE) {
		h = ctx->h;
	    }
	    else {
		h = ctx->ops->op_open(ctx);
		if (h == INVALID_HANDLE_VALUE) {
		    win32err = GetLastError();
		    if (win32err == ERROR_FILE_NOT_FOUND || win32err == ERROR_PATH_NOT_FOUND) {
			zip_error_set(&ctx->error, ZIP_ER_READ, ENOENT);
			return -1;
		    }
		}
	    }

	    success = _zip_stat_win32(h, st, ctx);
	    win32err = GetLastError();

	    /* We're done with the handle, so close it if we just opened it. */
	    if (h != ctx->h) {
		CloseHandle(h);
	    }

	    if (success < 0) {
		/* TODO: Is this the correct error to return in all cases? */
		zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(win32err));
		return -1;
	    }
	}
	return sizeof(ctx->st);
    }

    case ZIP_SOURCE_SUPPORTS:
	return ctx->supports;

    case ZIP_SOURCE_TELL:
	return (zip_int64_t)ctx->current;

    case ZIP_SOURCE_TELL_WRITE: {
	LARGE_INTEGER zero;
	LARGE_INTEGER offset;

	zero.QuadPart = 0;
	if (!SetFilePointerEx(ctx->hout, zero, &offset, FILE_CURRENT)) {
	    zip_error_set(&ctx->error, ZIP_ER_TELL, _zip_win32_error_to_errno(GetLastError()));
	    return -1;
	}

	return offset.QuadPart;
    }

    case ZIP_SOURCE_WRITE: {
	DWORD ret;
	if (!WriteFile(ctx->hout, data, (DWORD)len, &ret, NULL) || ret != len) {
	    zip_error_set(&ctx->error, ZIP_ER_WRITE, _zip_win32_error_to_errno(GetLastError()));
	    return -1;
	}

	return (zip_int64_t)ret;
    }

    default:
	zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
	return -1;
    }
}


static int
_win32_create_temp_file(_zip_source_win32_read_file_t *ctx) {
    zip_uint32_t value;
    /*
    Windows has GetTempFileName(), but it closes the file after
    creation, leaving it open to a horrible race condition. So
    we reinvent the wheel.
    */
    int i;
    HANDLE th = INVALID_HANDLE_VALUE;
    void *temp = NULL;
    PSECURITY_DESCRIPTOR psd = NULL;
    PSECURITY_ATTRIBUTES psa = NULL;
    SECURITY_ATTRIBUTES sa;
    SECURITY_INFORMATION si;
    DWORD success;
    PACL dacl = NULL;

    /*
    Read the DACL from the original file, so we can copy it to the temp file.
    If there is no original file, or if we can't read the DACL, we'll use the
    default security descriptor.
    */
    if (ctx->h != INVALID_HANDLE_VALUE && GetFileType(ctx->h) == FILE_TYPE_DISK) {
	si = DACL_SECURITY_INFORMATION | UNPROTECTED_DACL_SECURITY_INFORMATION;
	success = GetSecurityInfo(ctx->h, SE_FILE_OBJECT, si, NULL, NULL, &dacl, NULL, &psd);
	if (success == ERROR_SUCCESS) {
	    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
	    sa.bInheritHandle = FALSE;
	    sa.lpSecurityDescriptor = psd;
	    psa = &sa;
	}
    }


#ifndef MS_UWP
    value = GetTickCount();
#else
    value = (zip_uint32_t)GetTickCount64();
#endif

    for (i = 0; i < 1024 && th == INVALID_HANDLE_VALUE; i++) {
	th = ctx->ops->op_create_temp(ctx, &temp, value + i, psa);
	if (th == INVALID_HANDLE_VALUE && GetLastError() != ERROR_FILE_EXISTS)
	    break;
    }

    if (th == INVALID_HANDLE_VALUE) {
	free(temp);
	LocalFree(psd);
	zip_error_set(&ctx->error, ZIP_ER_TMPOPEN, _zip_win32_error_to_errno(GetLastError()));
	return -1;
    }

    LocalFree(psd);
    ctx->hout = th;
    ctx->tmpname = temp;

    return 0;
}


static int
_zip_seek_win32_u(HANDLE h, zip_uint64_t offset, int whence, zip_error_t *error) {
    if (offset > ZIP_INT64_MAX) {
	zip_error_set(error, ZIP_ER_SEEK, EOVERFLOW);
	return -1;
    }
    return _zip_seek_win32(h, (zip_int64_t)offset, whence, error);
}


static int
_zip_seek_win32(HANDLE h, zip_int64_t offset, int whence, zip_error_t *error) {
    LARGE_INTEGER li;
    DWORD method;

    switch (whence) {
    case SEEK_SET:
	method = FILE_BEGIN;
	break;
    case SEEK_END:
	method = FILE_END;
	break;
    case SEEK_CUR:
	method = FILE_CURRENT;
	break;
    default:
	zip_error_set(error, ZIP_ER_SEEK, EINVAL);
	return -1;
    }

    li.QuadPart = (LONGLONG)offset;
    if (!SetFilePointerEx(h, li, NULL, method)) {
	zip_error_set(error, ZIP_ER_SEEK, _zip_win32_error_to_errno(GetLastError()));
	return -1;
    }

    return 0;
}


static int
_zip_win32_error_to_errno(DWORD win32err) {
    /*
    Note: This list isn't exhaustive, but should cover common cases.
    */
    switch (win32err) {
    case ERROR_INVALID_PARAMETER:
	return EINVAL;
    case ERROR_FILE_NOT_FOUND:
	return ENOENT;
    case ERROR_INVALID_HANDLE:
	return EBADF;
    case ERROR_ACCESS_DENIED:
	return EACCES;
    case ERROR_FILE_EXISTS:
	return EEXIST;
    case ERROR_TOO_MANY_OPEN_FILES:
	return EMFILE;
    case ERROR_DISK_FULL:
	return ENOSPC;
    default:
	return 0;
    }
}


static int
_zip_stat_win32(HANDLE h, zip_stat_t *st, _zip_source_win32_read_file_t *ctx) {
    FILETIME mtimeft;
    time_t mtime;
    LARGE_INTEGER size;
    int regularp;

    if (!GetFileTime(h, NULL, NULL, &mtimeft)) {
	zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(GetLastError()));
	return -1;
    }
    if (_zip_filetime_to_time_t(mtimeft, &mtime) < 0) {
	zip_error_set(&ctx->error, ZIP_ER_READ, ERANGE);
	return -1;
    }

    regularp = 0;
    if (GetFileType(h) == FILE_TYPE_DISK) {
	regularp = 1;
    }

    if (!GetFileSizeEx(h, &size)) {
	zip_error_set(&ctx->error, ZIP_ER_READ, _zip_win32_error_to_errno(GetLastError()));
	return -1;
    }

    zip_stat_init(st);
    st->mtime = mtime;
    st->valid |= ZIP_STAT_MTIME;
    if (ctx->end != 0) {
	st->size = ctx->end - ctx->start;
	st->valid |= ZIP_STAT_SIZE;
    }
    else if (regularp) {
	st->size = (zip_uint64_t)size.QuadPart;
	st->valid |= ZIP_STAT_SIZE;
    }

    return 0;
}


static int
_zip_filetime_to_time_t(FILETIME ft, time_t *t) {
    /*
    Inspired by http://stackoverflow.com/questions/6161776/convert-windows-filetime-to-second-in-unix-linux
    */
    const zip_int64_t WINDOWS_TICK = 10000000LL;
    const zip_int64_t SEC_TO_UNIX_EPOCH = 11644473600LL;
    ULARGE_INTEGER li;
    zip_int64_t secs;
    time_t temp;

    li.LowPart = ft.dwLowDateTime;
    li.HighPart = ft.dwHighDateTime;
    secs = (li.QuadPart / WINDOWS_TICK - SEC_TO_UNIX_EPOCH);

    temp = (time_t)secs;
    if (secs != (zip_int64_t)temp)
	return -1;

    *t = temp;
    return 0;
}