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11111111 111111 1111111 11 11 11 01100000 011000 11 0110000 11 011 0111 011 011 011 0011 011 11 011 01111 011 01111111 011 011 011111110 011 011011 011 0110000 011 011 0110000 11 011 011 011011 011 011 11 011 11 011 011 01111 011111111 01111110 011111110 011 011 0011 00000000 000000 0000000 00 00 00 Binary File Editor Version 0.4 (c) 1990, Stefan Strack ------------------------------ DISCLAIMER This program is shareware and may be distributed freely, provided neither this documentation nor the program are modified. No charges exceeding the cost of distribution may be asked. The author disclaims all liability of any sort and all warranties on this program. Especially, the author is not responsible for any violations of the copyright law that may result from illegal usage of this program. If you find this program useful, consider sending a contribution of $15 (or any amount) to: Stefan Strack Dept. Biology SUNY Albany 1400 Washington Ave. Albany, NY 12222 Your suggestions, comments and bug reports are also very much appreciated. Please write to me at the above address or send email to: Bitnet: ss9557@albny1vx Internet: ss9557@leah.albany.edu DOS is a registered trademark of Microsoft; UNIX is a registered trademark of AT&T. ------------------------------ WHAT IS EDBIN? Edbin is a string editor for binary files, a utility for file encryption, and a translator into email-compatible ASCII files. The binary file editor is reminiscent of the DOS line-editor EDLIN, but has string-, as well as byte-level editing capabilities. Edbin can be run interactively or from the DOS command line; commands are single-letter mnemonics. There are no windows or pull-down menus. In short, Edbin features: o Binary file editing: Edbin allows you to easily edit strings in program files, while making sure the programs will still run afterwards. This might be useful for changing offending program messages, or even producing a foreign-language version of a program. In addition, the editor lets you quickly scan an "undocumented" program to find out what it is doing without actually running it. Like DEBUG, Edbin can also be used for binary-file patching. o File encryption: Edbin offers fast and easy, yet very secure file encryption to protect your personal files from prying eyes. o ASCII file translation: Edbin converts program files into pure text (ASCII) files. These files can then be sent via ASCII-only email links or with ASCII transfer protocols and converted back into binary files at the receiving end. A built-in circular-redundancy-check (CRC) checks file integrity after transfer. You can chose between a generic hexadecimal format or a more compact, base-64 format that requires Edbin on both the sending and receiving end. ------------------------------ REQUIREMENTS Edbin will run under DOS 2.0 and up on any IBM-compatible machine. It requires less than 95K RAM (plus space for the command interpreter if you shell out to DOS). Since Edbin runs entirely in text-mode, it will work with any video card. If you are editing large files, a fast hard disk is preferable over a slow floppy drive. Even better in terms of access speed is editing files from a RAM drive. ------------------------------ COMMAND OVERVIEW The syntax for starting up Edbin is: edbin [/d] [/<command> ..] filespec Edbin will also accept the UNIX-style hyphen ('-') in place of the DOS switch ('/'). The obligatory parameter 'filespec' tells Edbin which file to work on. The optional switch /d will force editing on-disk (see IN-MEMORY vs. ON-DISK EDITING). The /<command> switch will execute said single-letter command (see COMMAND LINE OPTIONS), optionally pass a command argument, and exit back to DOS. After invoking edbin (without /<command> argument), the editor displays a '*' prompt and waits for a command. The following is a brief summary of available single-letter (or address-) commands; a more detailed description can be found later in the manual. Some of these commands prompt the user for arguments (such as the filename to write to disk). Prompts or any work in progress can be cancelled by hitting ^C (Control-C or Control-Break); the user is then returned to the editor command prompt ('*'). N (Next) The editor displays the next string after the current file offset and goes into editing mode. <Enter> is a synonym for N. n (where n is an integer >= 0) The string immediately after file offset n (or if n falls within a string, beginning with n), is edited. U Undo last string edit. L List all strings. S Search and replace. n:xy Write the string xy to file offset n. n#m Write the decimal byte m to file offset n. n$m Write the hexadecimal byte m to file offset n. C Encrypt/Decrypt file. V Validate file (CRC). H Translate to hexadecimal ASCII file. B Translate to base-64 ASCII file. I Translate to binary file. W Write edited file to disk. Q Quit Edbin. X Save the current file and exit Edbin. E Edit another file. ? Display a help screen. = Show current editor settings. "xy Set search string to xy. / is a synonym for " (Default=""). _n Set minimum string length to n (Default=8). [n Set working range start to file offset n (DEFAULT=0). ]n Set working range stop to file offset n (DEFAULT=filesize-1). ! Toggle overwrite mode (Default=OFF). @ Toggle include extended characters (127-255, Default=OFF). : Toggle prompting (Default=OFF). . Reset editor settings to default. > Start DOS shell (>prog executes prog and returns to Edbin). ' (single quote) Void command, the following characters are ignored. The quote serves as a comment leader in input-redirection files. ------------------------------ IN-MEMORY VS. ON-DISK EDITING Edbin can edit files up to 58 Kbytes in size in memory. Files larger than that (as large as your disk space permits) are edited "on-disk", i.e. modifications are directly written to disk rather than to memory. When a file is being edited on-disk, the program's status line will inform you that it is "modifying on disk". In this case, you should better have a back-up copy of your edited file at hand, since all edits will be final. You can force on-disk editing of files smaller than 58K with the '/D' command switch (see COMMAND LINE OPTIONS). Forced on-disk editing is useful when editing commands are given on the DOS command line. On-disk editing is obviously slower than editing in memory, but speed can be improved when large files are edited from a RAM drive. ------------------------------ COMMAND LINE OPTIONS Edbin can be run interactively or by specifying commands on the DOS command line. All command line arguments except for the '/d' switch and the filename argument are passed on to the command interpreter as though they were input from an editor prompt. If the specified file has not been modified in memory after all command line commands have been processed, Edbin will exit. For example: edbin /_12 /l /v foo.exe will list all strings of length >= 12, compute a CRC in foo.exe and exit. edbin foo.exe /s /abc /xyz will substitute all occurences of the string "abc" with "xyz" in foo.exe. If any strings were substituted and foo.exe was edited in memory, Edbin will wait for the user to issue an exit-command interactively. Otherwise, it will exit to DOS after processing the command line arguments. If you specify edbin foo.exe /s /abc /xyz /d editing will be done directly on-disk, therefore Edbin will not wait for you to save your changes manually. Another example: edbin /h / /A$20File$20Comment foo.exe This command will translate foo.exe into an hexadecimal ASCII file (/h), accept the default file name foo.hex (/), and use the file ASCII file comment "A File Comment" (the $20 stands for the space character (hexadecimal 20), see USING SPECIAL CHARACTERS). Since foo.exe will not have been modified after this command, Edbin will exit to DOS. ------------------------------ THE EDITOR The binary file editor will preserve the length of the edited file, thus trying to maintain the integrity of an executable file. The following sections will describe the editing functions of Edbin in more detail. ------------------------------ WHAT IS A STRING? The binary file editor operates on strings. A string, as defined by Edbin, is a sequence of printable ASCII characters. By default, a string consists of 8 or more characters of ASCII value 9 (vertical tab) or 32-126 (Space to ~). The default minimum string length (8) can be changed with the _ (underscore) command (see EDITOR SETTINGS). If the "include extended characters" switch is toggled on (@ command), the string definition includes the IBM extended character set (127-255). Editable strings can also be delimited with the work range ('[' and ']') or search string ('"') commands. ------------------------------ EDITING A LINE If the 'N' (Next, or simply <Enter>) command is given, Edbin will enter editing mode for the next string after the current file offset. If you enter a file offset n (0 <= n < filesize), the next string after n will be opened for editing. If no string is found after the current file offset, Edbin returns to the beginning of the file (or to the beginning of the work range if specified). Let us suppose you hit <Enter> after starting Edbin. The display might look like this: * 517:This is the first string in this file 517:_ This means that the editor found the string "This is .." starting at file offset 517. You can now hit <Enter> to leave the string as is and return to the command prompt, or type a new string (including editing characters, see EDITING KEYS) and hit <Enter> to replace the old string. The consequences of modifying a string depend on the setting of the ! (overwrite) toggle (see EDITOR SETTINGS): if overwrite is toggled off (default), the replacement string will be truncated to the length of the original string, or padded with spaces if it is shorter than the original string. If overwrite is toggled on, the replacement string will be written without truncating or padding, even past the boundary of the original string. "Overwrite ON" is to be used with caution, since it lets you corrupt a file's executability. You can undo your last change with the 'U' command; however, this will only work if you have not written past the original string's end. ------------------------------ EDITING KEYS When in string-editing mode, the following characters (in addition to the code-characters $ and #, see USING SPECIAL CHARACTERS) have a special meaning: . (period) = copy character * (asterics) = copy template @ (at) = skip template ^ (caret) = toggle typeover/insert ~ (tilde) = delete character ' (single quote) = quote character If you want to use these characters as such, precede them with a single quote. These keys work similar to DOS editing keys (F1-F4, INS, DEL), but have to be embedded in the string and take effect only after hitting <Enter>. This may be unfamiliar to users of full-screen editors, etc., but has the advantage that input can be redirected from a file. . (period) This is Edbin's "F1" (or right-arrow) key. It copies the next character in the original string (template) to the edited string. Example: 2089:Cannot locate file 2089:.......find file<Enter> -> 2089:Cannot find file * (asteriks) Corresponds to F2 or F3 (if last character). This key copies all characters up to the character following '*' from the template to the edited string. If the character following '*' does not occur in the template or if '*' is the last character entered, the entire remainder of the template is copied. Example: 9002:FOOBAR - The Electronic Piggybank V1.0 (C) 1988-89 by Oddball Software 9002:*V2*<Enter> -> 9002:FOOBAR - The Electronic Piggybank V2.0 (C) 1988-89 by Oddball Software @ (at) This key works similar to DOS's F4. All characters of the template up to the character following '@' are skipped. If the character after '@' is not found in the template or if '@' is the last character entered, the entire remaining template is skipped. Example: 17950:Hit any key and say your prayers 17950:@say*, then press ESC<Enter> ->17950:say your prayers, then press ESC ^ (caret) This key toggles between "Insert" and "Typeover" mode. When you start editing a string, you are in typeover mode, i.e. the template is overwritten with your key strokes. What you type after the first '^' is inserted before the current position in the template. Typeover is turned back on after the next '^', a.s.o. Example: 315:Fatal error: allocation table thrashed --- Sorry 315:*:^ file*<Enter> -> 315:Fatal error: file allocation table thrashed --- ~ (tilde) '~' "deletes" the current character in the template by advancing a pointer to the next template character. Example: 9010:Unregistered Copy 9010:~~R*<Enter> ->9010:Registered Copy Remember: - quote if you want an editing character to appear in the string (e.g."FILE'.EXT") - use two quotes for one quote to appear (e.g."don''t") - use the "undo" command in case a string gets fouled up ------------------------------ DIRECT WRITE You can write to a file even outside a string by issuing a direct-write command. This can be used for patching programs. For example, by issuing 1203:Writes directly into binary file at the command prompt, the string "Writes directly .." will be written starting at file offset 1203. Another example: 2344#065 will write the decimal character 65 ('A') to file offset 2344. Or: 701$1B will write the hexadecimal character 1B (ESC) to file offset 701. You can mix character, decimal and hexadecimal designations as in: 10:Hello,$20world#033 which will write the string "Hello, world!" to file offset 10 (see USING SPECIAL CHARACTERS for usage of decimal and hexadecimal character codes). ------------------------------ LIST STRINGS The 'L' (List) command will list all strings conforming to the current editor settings. The format for each string is: n:string where n is the file offset at which "string" starts. ------------------------------ SEARCH AND REPLACE The 'S' (search and replace) command will replace every occurence of a prompted search string with a prompted replacement string. You can substitute non-printing characters by using their decimal or hexadecimal values (see USING SPECIAL CHARACTERS). The actions of this command as for the 'N' command depend on the setting of the "overwrite toggle" (!). If "overwrite OFF" the replacement string is padded or truncated to fit the length of the search string; if "overwrite ON" the replacement string can write past the end of the search string. You can restrict search-and-replace by setting the working range delimiters ('[' and ']') or by enabling prompting (':', see EDITOR SETTINGS). To simply search for a string, use the '"' command to set a search string (see EDITOR SETTINGS), and then enter 'L' for a listing or hit <Enter> to edit the next matching string. ------------------------------ USING SPECIAL CHARACTERS You can incorporate any non-printable character (except ASCII 0) into a prompted string by using the decimal code #nnn or the hexadecimal code $nn. nnn in the decimal code is a number between 001 and 255 representing the ASCII character with that value. nn in the hexadecimal code is a number between 01 and FF representing ASCII values 1 through 255. You cannot represent ASCII 0 this way, because the null character is used as the string terminator in C, the computer language used for implementing Edbin (the only exception is single-byte "direct write": 911$00 or 911#000 does indeed write the null character to offset 911). For example, you could input the string "ABC" as "#065#066#067", or "$41$42$43" (or any combination of ASCII, decimal, or hexadecimal codes). Edbin will interpret "#32" or "#0FF" as literal strings, since they do not conform to the special codes format (# must be followed by three decimal digits). You can use the single quote (') to force interpretation as a literal string (E.g. "'$20" translates into the string "$20"); two consecutive single quotes translate into one single quote. Special characters are accepted in prompts for the encryption/decryption password, search and replace string, and during string editing. In addition, you can use special character codes to use, e.g. embedded blanks on the DOS command line, as in: edbin /d /c /cryptic$20password foo.exe ------------------------------ EDITOR SETTINGS Edbin allows customizing the editor by changing a number of default settings. _n (set minimum string length to n): By default, Edbin considers a sequence of eight or more ASCII characters (32-126), including the horizontal tab character (9) as a string for listing or editing. You can change the default minimum string length to any value between 1 and 255 with the _ (underscore) command. "xyz (set search string to "xyz"): By specifying a global search string, you can delimit the strings that Edbin will list or display for editing. For example, specifying "Error will cause the editor to skip all strings that do not contain the substring "Error". A specified search string will remain in effect until you clear it again (" followed by <Enter>). The forward slash (/) is a synonym for ", and must be used if the search string is specified on the command line, since DOS will garble command line arguments if an unmatched quote is found. [n (set working range start to n). By default, Edbin will work on the entire edited file (from file offset 0 to EOF). You can tell Edbin to ignore all strings before a given file offset by issuing the left square-bracket command. The current file offset is reset to the beginning of the work range after this command. ]n (set working range stop to n): Similarly, the right square-bracket will cause the editor to ignore strings after the specified file offset. : (toggle prompting): With the default "prompting OFF", the editor will use the global settings for working range and search string for all operations. With prompting enabled, however, you will be prompted for range delimiters and, if applicable, a search string for every command you give. ! (toggle overwrite mode): Edbin will preserve the length of an edited file, i.e. you cannot insert or delete characters, since this would most likely corrupt an executable file. As an additional safeguard, edited strings are normally truncated to the length of the original string before they are written back (i.e. overwrite is OFF by default). Likewise, edited strings shorter than the original are padded with blanks. The ! (exclamation mark) toggle allows you to override truncating or padding; i.e. strings are written exactly as entered, even past the boundaries of the original string. Overwrite mode toggled ON should obviously be used with caution, since you might inadvertently overwrite binary instructions. The behavior of the search and replace function is similarly dependend on the setting of the overwrite toggle. = (show settings): The equal-sign displays all current editor settings; defaults are shown in brackets. @ (toggle include extended characters): By default, Edbin will consider characters in the IBM extended character set (127-255) as not part of an editable string. If @ (at) is toggled ON, Edbin will display and edit strings containing extended characters. . (reset to default): The period resets all editor settings to their defaults. ------------------------------ OFF-LINE EDITING The output of the "List strings" command can be processed as a list of "Direct write" commands. This together with DOS input/output redirection allows you to dump all strings in a program to a text file for editing with your favorite pure-ASCII editor. Command prompts and messages are written directly to the console, so they will not be redirected to a file. After editing, these string can be written back into the original program file. An example: edbin /l foo.exe > strings.txt will write all strings with their starting file offset to the file strings.txt. After editing the file strings.txt, you call up Edbin with input redirection: edbin /d foo.exe < strings.txt The /d switch forces on-disk editing, so the editor will write all changes directly to foo.exe on disk before exiting when EOF is encountered in strings.txt. Otherwise you would have to add commands for saving and exiting at the end of strings.txt. The off-line edited file may contain comments, since Edbin will ignore lines that start with a ' (single quote). Direct writes will write a string irrespective of the previous contents of the file address pointed to. So you have to take care not to change file addresses or exceed the length of the original string while off-line editing. Alternatively, you could change direct write commands into addressed string editing commands as in: 1021:This is a string becomes 1021 This is a string This way, provided overwrite is OFF, the edited string will be clipped or padded as needed. ------------------------------ ENCRYPTING AND DECRYPTING Edbin offers a simple, yet secure way of password-protecting your files. When you enter 'C' (Crypt) at the prompt or from the DOS command line, you will be prompted for a password (up to 127 characters). The password may contain codes for special characters (see USING SPECIAL CHARACTERS). Your file is then scrambled using your password as a key. The process is symmetrical, so decryption simply entails entering 'C' again and retyping the password. The encryption/decryption process is sensitive to case and leading or trailing blanks. Consequently, the password must be retyped exactly as entered for encryption. Also, the working range delimiters must be set identically for encryption and decryption (usually to the beginning and the end of the file). For those interested in implementation details: encryption/decryption works by XORing each byte with the output of a "pseudo" random-number generator. The password is used to produce a unique initial seed. The implementation of this random-number generator was verified to have a period of 2^32 and no "singularities". Edbin encryption should thus be very hard to break. ------------------------------ ASCII-FILE TRANSLATION Transfer of binary files via telephone lines across the country or, worse, across the ocean can dramatically increase your monthly phone bill. The alternative are free networks, such as Internet or Bitnet, that connect mostly university computer centers. Some even connect to overseas, such as Bitnet which allows exchange with EARN sites in Europe. The disadvantage: most links are ASCII-only or have rather unreliable binary transfer capabilities. How can you still send binary files via email? The solution is to convert binary files into a text file, email the text file, and convert it back to the original binary file at the receiving end. Most straightforward: send a hexadecimal dump of the binary file (each byte is represented as a 2-digit hexadecimal number). While this method is rather easily implemented, it has a size problem: the text file is more than twice as large as the original. The UNIX atob/btoa utilities use a space-saving base-85 encoding scheme, which translates groups of four bytes into 5 ASCII characters, increasing the size of the emailed file by slightly more than 25%. uuencode/uudecode employ a base-64 code that is similar but not identical to the Edbin base-64 format. The Edbin two-way file translator implements two ASCII-file translation formats, both with built-in check for file integrity. The generic hexadecimal format is easy to generate and decode with a few lines of program code, hence does not require the presence of Edbin on both sides of transmission. The base-64 format is more compact than hexadecimal, but requires Edbin on both ends for encoding and decoding. ------------------------------ HEXADECIMAL TRANSLATION FORMAT The 'H' command invokes the binary-to-hexadecimal translator. The currently edited file is taken as input and a hexadecimal ASCII translation is written to a file with the default extension ".HEX". You may optionally include a one- line comment which will be displayed when the file is decoded back to binary again. You can encode "in pieces" (necessary if your email link has a transmission size limit or the file would not fit on a floppy) by setting the work range delimiters or enabling prompting (see EDITOR SETTINGS). The ASCII- to-binary translator can incrementally build the original program file from a number of split-up ASCII files. The first line in a hexadecimal format file is a header that contains the translation format, the name of the encoded binary file, its size and a 16-bit CRC for file integrity check. The next line contains the optional file comment, and is followed by the hexadecimal text. Each byte is encoded by 2 hexadecimal digits; there is a line-break after 80 characters, but no spaces between pairs of digits. The resulting text file is a little more than twice the size of the binary file it encodes. ------------------------------ BASE-64 TRANSLATION FORMAT Entering 'B' from the command prompt or from the command line starts translation of the current work file into base-64 ASCII format. In this format groups of 3 bytes are translated into 4 text characters (of a set of 64), resulting in a file that is only about 35% larger than the binary file it encodes. The set of 64 characters used for encoding is included with the base-64 format file as a "translation table" after the file header. This translation table is used when decoding the base-64 file. For encoding, Edbin uses a default translation table consisting of digits, upper- and lower-case letters plus the comma and the semicolon. If your mailer happens to garble or substitute one of the characters used, you can change the default translation table by editing EDBIN.EXE: search for a string containing 012345 and retype the modified string or use search-and-replace ('S'). All printing characters (ASCII 32 - 126) are valid, but no character may appear more than once in the translation table. The modification will be in effect after saving EDBIN.EXE and restarting the editor. The base-64 translator's operation is otherwise identical to the binary-to-hexadecimal translator (see above). ------------------------------ TRANSLATING TO BINARY FORMAT The 'I' command will translate both hexadecimal and base-64 encoded ASCII files back into the original binary files. It takes as input the current work file, which must be in one of the ASCII formats that Edbin supports, and writes the binary file to disk (the default file name is taken from the file header). Initially, the text-to-binary translator tries to establish the encoding format by searching for the file header. It will ignore everything before the file header (e.g. the email message header), and ignore all lines after the number of bytes specified in the file header have been decoded. When done, the translator compares the CRC of the newly created binary file with the CRC in the file header and reports a warning in case the file integrity check failed. Edbin is also able to decode hexadecimal ASCII files that lack a file header, i.e. files created with a hexadecimal dump program other than Edbin (e.g. the UNIX "od -h" utility). Hexadecimal decoding is relatively free-format, i.e. any number of spaces or line-breaks are allowed between pairs of digits. It is possible to incrementally build one large binary file by decoding several ASCII files and "appending" to the growing binary file. ------------------------------ FILE VALIDATION Upon entering 'V', Edbin will compute and display a 16-bit circular- redundancy-check (CRC) for the edited file. This can be used to authenticate programs. The same CRC is written to the file header when translating files to ASCII-format. ------------------------------ WRITING A FILE AND EXITING The 'W' command writes the currently edited file to disk, the 'X' command saves the file if it was modified and then exits Edbin, and entering 'Q' quits Edbin without saving changes. It is not necessary to save the file if it was "modified on disk", since all changes will have been written to the disk immediately. It is possible to save part of a file by adjusting the range delimiters ('[',']', see EDITOR SETTINGS). This comes in handy if you want to split up a file that is too large for your text editor or floppy disk. Edbin also allows you to append the edited file to an existing file. ------------------------------ BUSY DISPLAYS Edbin has two displays indicating it is busy doing something. When searching for strings, validating a file, etc., it will display a running counter of the current file offset. When a file is written to disk during translation to binary, hexadecimal or base-64 format, a pulsating square is displayed. ------------------------------ RELEASE HISTORY Version 0.1, 5/19/90 Edbin has its roots in Bincode, a simple binary-hexadecimal translation utility I wrote for emailing programs. The string editor was inspired by the shareware program "Strings" (author unknown), which dumps strings in programs to the screen. Version 0.2, 7/8/90 Minor and major bugs are fixed. Inspired by uuencode/uudecode, version 0.2 supports a modifiable translation table for the base-64 translator. Version 0.3, 8/24/90 An "undo" command, special editing keys, and partial write were added. Version 0.4, 9/9/90 Bug-fix in partial write