PSIONICS FILE - WORD.FMT
========================
Format of Word files
Last modified 1996-01-18
========================
Word files can be encrypted with a password. Encryption affects only the
header and data record type 8 (see below).
A word file begins with a header of the following form (U indicates values
for unencrypted files, and E values for encrypted files):
Offset 0 (cstr): "PSIONWPDATAFILE"
Offset 16 (word): format version number (U: 1, E: 256)
Offset 18 (word): encryption algorithm version (U: 0, E: 1)
Offset 20 to 28: encryption key check value (all $EA if unencrypted)
Offset 29 to 35: copy of offset 20 to 26
Offset 36 (word): U: $EAEA, E: 0
Offset 38 (word): unused
The rest of the file consists of records. All records have the form:
Offset 0 (word): record type
Offset 2 (word): size of data portion (L)
Offset 4 to L+3: data portion
Word files have record types 1 to 9; the word processor application creates
them in numerical order of type. Exactly one record of each type is used,
except that there may be more than one record of types 6 and 7.
All distances and font sizes are in units of 0.05 points (i.e. a value of
1440 represents one inch). All font names are represented by standard code
numbers:
-1 = Inherited (where permitted)
0 = Courier 17 = Emperor 40 = Greek
1 = Pica 18 = Madeleine 41 = Kana
2 = Elite 19 = Zapf Humanist 42 = Hebrew
3 = Prestige 20 = Classic 44 = Russian
4 = Letter Gothic 24 = Times Roman 48 = Narrator
5 = Gothic 25 = Century 49 = Emphasis
6 = Cubic 26 = Palatino 50 = Zapf Chancery
7 = Lineprinter 27 = Souvenir 52 = Old English
8 = Helvetica 28 = Garamond 55 = Cooper Black
9 = Avant Garde 29 = Caledonia 56 = Symbol
10 = Spartan 30 = Bodoni 57 = Line Draw
11 = Metro 31 = University 58 = Math 7
12 = Presentation 32 = Script 59 = Math 8
13 = APL 33 = Script PS 60 = Dingbats
14 = OCR A 36 = Commercial Script 61 = EAN
15 = OCR B 37 = Park Avenue 62 = PC Line
16 = Standard Roman 38 = Coronet
Record type 1 holds information about the file. It is always 10 bytes:
Offset 0 (word): cursor position within text record (type 8)
Offset 2 (byte): each set bit indicates a character type should be shown
as symbols:
Bit 0: tabs
Bit 1: spaces
Bit 2: carriage returns
Bit 3: soft hyphens
Bit 4: forced line breaks
Offset 3 (byte): (Series 3a only)
Bits 0 to 1: status window: 0=none, 1=narrow, 2=wide
Bits 4 to 5: zoom state: 0=smallest, ... 3=largest
Offset 4 (byte): 0=style bar off, 1=style bar on
Offset 5 (byte): 0=file type is paragraph, 1=file type is line
Offset 6 (byte): outlining level
Offset 7 (byte): unused
Offset 8 (word): unused
Record type 2 holds information about printer set-up. It is
always 58 bytes:
Offset 0 (word): page width
Offset 2 (word): page height
(Note: the above fields assume that the paper orientation is "portrait")
Offset 4 (word): left margin
Offset 6 (word): top margin
Offset 8 (word): width of printing area
Offset 10 (word): height of printing area
(Note: these four fields have only been checked for portrait)
Offset 12 (word): header offset (bottom of header to top of text)
Offset 14 (word): footer offset (bottom of footer to bottom of text)
Offset 16 (word): paper orientation: 0=portrait, 1=landscape
Offset 18 (word): unknown
Offset 20 (word): first page to print (1=first page)
Offset 22 (word): last page to print ($FFFF=end of file)
Offset 24 (word): header font code number
Offset 26 (byte): header style
Bit 0: underline
Bit 1: bold
Bit 2: italic
Bit 3: superscript
Bit 4: subscript
Offset 27 (byte): unused
Offset 28 (word): header font size
Offset 30 (byte): header alignment:
0 = left
1 = right
2 = centered
3 = justified
4 = two column
5 = three column
Offset 31 (byte): header on first page: 0=no, 1=yes
Offset 32 to 39: as 24 to 31, but apply to footer, not header
Offset 40 (word): page number of first page minus 1
Offset 42 (word): number of pages
Offset 44 (word): page number style: 0="1,2,3", 1="I,II,III", 2="i,ii,iii"
Offset 46 (word): base font code number
Offset 48 (byte): base style (as offset 26)
Offset 49 (byte): unused
Offset 50 (word): base font size
Offset 52 (byte): paper size code:
0 = A4 (11906 x 16838)
1 = Custom
2 = Executive (10440 x 15120)
3 = Legal (12240 x 20160)
4 = Letter (12240 x 15840)
5 = Monarch ( 5580 x 10800)
6 = DL ( 6236 x 12472)
Offset 53 (byte): widows/orphans allowed: 0=no, 1=yes
Offset 54 (long): unused
The base font code, style, and font size are unused by Word (and should be set
to code 0, style 0, size 240). Other applications using this record layout may
use them and provide means to set them.
Record type 3 holds information about the printer driver:
Offset 0 (byte): printer driver model number
Offset 1 (cstr): printer driver library
A printer driver library can support several similar printers; the model number
specifies which is selected.
Record types 4 and 5 hold cstrs giving the header and footer text respectively.
Record types 6 and 7 have a similar layout. Record type 6 describes a style
and uses all 80 bytes. Record type 7 describes an emphasis and uses only the
first 28 bytes.
Offset 0 to 1: short code, as uppercase letters
Offset 2 (cstr): full name
Offset 18 (byte):
Bit 0: 0=style, 1=emphasis
Bit 1: set if style or emphasis undeletable
Bit 2: set for default style or emphasis
Offset 19 (byte): unused
Offset 20 (word): font code number (can be inherited)
Offset 22 (byte): style (bits inherited must be clear in this byte)
Bit 0: underline
Bit 1: bold
Bit 2: italic
Bit 3: superscript (available in emphasis only)
Bit 4: subscript (available in emphasis only)
Offset 23 (byte): unused
Offset 24 (word): font size
Offset 26 (byte):
Bit 0: inherit underline setting
Bit 1: inherit bold setting
Bit 2: inherit italic setting
Bit 3: inherit superscript setting (available in emphasis only)
Bit 4: inherit subscript setting (available in emphasis only)
Offset 27 (byte): unused
Offset 28 (word): left indent
Offset 30 (word): right indent
Offset 32 (word): first line indent
Offset 34 (word): alignment: 0=left, 1=right, 2=centred, 3=justified
Offset 36 (word): line spacing
Offset 38 (word): space above paragraph
Offset 40 (word): space below paragraph
Offset 42 (byte): spacing controls:
Bit 0: set to keep with next
Bit 1: set to keep together
Bit 2: set to start new page
Offset 43 (byte): unused
Offset 44 (word): Outline level (1 to 9)
Offset 46 (word): number of tab stops set
Offset 48 (word): position of first tab stop
Offset 50 (word): type of first tab stop: 0=left, 1=right, 2=centred
Offset 52 to 55: as offsets 48 to 51 for second tab stop
Offset 56 to 79: as offsets 48 to 51 for third to eighth tab stops
Record type 8 holds the actual text. The following bytes have special
meanings:
0 = paragraph separator
7 = unbreakable hyphen
14 = soft hyphen (displayed only if used to break line)
15 = unbreakable space
The record is modified in encrypted files.
Record type 9 consists of a sequence of blocks giving the style and emphasis
for the text; each block covers some number of consecutive bytes, and the
blocks between them cover the entire text. No block crosses a paragraph
boundary, but the last block of the paragraph includes the zero byte separating
it from the next paragraph. Each block is 6 bytes:
Offset 0 (word): number of bytes covered
Offset 2 to 3: shortcode of style applied
Offset 4 to 5: shortcode of emphasis applied
The last block should cover an extra byte (an imaginary extra zero separator),
so that the sum of the bytes covered is one more than the size of the type 8
record.
Encryption
----------
Word files can be encrypted with a password. If so, this fact is indicated
in the header (see above), and the type 8 record is modified.
The password is used to generate two 9 byte sequences, called the key value
and the key check value; there is no obvious relationship between the two
sequences. The key check value is written into the header, while the key
value is used for the actual encryption. The key value is generated with the
system call GenMaskInit; there is no documentation of the algorithm used to
generate the check value.
[Note: different passwords may generate the same key value but different key
check values, or vice versa (passwords "AA" and "AAA" are an example of the
latter). This can confuse Word badly.]
Encryption is carried out using the system call GenMaskEncrypt. For
convenience, the description is repeated here with an example.
The first 7 bytes of the key value are appended to all 9 to generate a 16
byte sequence. This is then repeated to generate a sequence of the same size
as the type 8 record, and placed in 1-to-1 correspondence with it. In other
words, for byte N of the type 8 record, the corresponding key byte is given
by byte N AND $F of the 16 byte sequence, counting from 0 (or, in C notation,
byte N % 16 % 9 of the 9 byte sequence). The key byte is then added to the
plain text byte, modulo $100, to get the encrypted byte.
For example, suppose that the text is a single paragraph containing:
Jackdaws love my 21 big sphinxes of quartz.
and the key value is:
$91 $20 $E3 $92 $42 $F9 $5C $57 $A9
(which corresponds to the password "AA") then the encrypted type 8 record
is determined as follows:
Text: J a c k d a w s l o v e m y
4A 61 63 6B 64 61 77 73 20 6C 6F 76 65 20 6D 79
Key: 91 20 E3 92 42 F9 5C 57 A9 91 20 E3 92 42 F9 5C
Encr: DB 81 46 FD A6 5A D3 CA C9 FD 8F 59 F7 62 66 D5
Text: 2 1 b i g s p h i n x e s
20 32 31 20 62 69 67 20 73 70 68 69 6E 78 65 73
Key: 91 20 E3 92 42 F9 5C 57 A9 91 20 E3 92 42 F9 5C
Encr: B1 52 14 B2 A4 62 C3 77 1C 01 88 4C 00 BA 5E CF
Text: o f q u a r t z .
20 6F 66 20 71 75 61 72 74 7A 2E
Key: 91 20 E3 92 42 F9 5C 57 A9 91 20
Encr: B1 8F 49 B2 B3 6E BD C9 1D 0B 4E
Of course, standard Kerchoffs techniques can be used to break the encryption.
|
|
