DragonFly On-Line Manual Pages

Search: Section:  

DS1991(3)                    One-Wire File System                    DS1991(3)


NAME

       DS1991 - 1152bit MultiKey iButton


SYNOPSIS

       Non-volatile memory with password protection.

       02 [.]XXXXXXXXXXXX[XX][/[ subkey0/reset.  hex_pwd | subkey0/password.
       hex_pwd | subkey0/secure_data.  hex_pwd | subkey0/id.  hex_pwd

       02 [.]XXXXXXXXXXXX[XX][/[ subkey1/reset.  hex_pwd | subkey1/password.
       hex_pwd | subkey1/secure_data.  hex_pwd | subkey1/id.  hex_pwd

       02 [.]XXXXXXXXXXXX[XX][/[ subkey0/reset.  hex_pwd | subkey2/password.
       hex_pwd | subkey2/secure_data.  hex_pwd | subkey2/id.  hex_pwd

       See the file man3/standard_mini.3so.

       ]]


FAMILY CODE

       02


SPECIAL PROPERTIES

   subkey[0|1|2]/reset.hex_pwd
       write-only, yes-no
       Initialize one of the three secure data areas and set a new password.

       The extension (hex_pwd) is the new 8-byte password in hexidecimal (e.g.
       password.000204006080A0C0E for bytes 0,2,4,6,8,10,12,14)

       The data must be "1" or "yes" to actually reset the subkey.

       Note: writing a password will clear any existing data and ID.

   subkey[0|1|2]/password.hex_pwd
       write-only, binary
       Change the password of one of the secure subkey areas without losing
       data.

       The extension (hex_pwd) is the existing 8-byte password in hexidecimal
       (e.g. password.00020406080A0C0E for bytes 0,2,4,6,8,10,12,14)

       The data portion is 8 bytes that will be used as a new password.

   subkey[0|1|2]/secure_data.hex_pwd
       read-write, binary
       Read or write data in one of the three sucure data areas.

       The extension (hex_pwd) is the existing 8-byte password in hexidecimal
       (e.g. password.00020406080A0C0E for bytes 0,2,4,6,8,10,12,14)

       The data portion binary data. Up to 48 bytes in each subkey area,
       starting at location 0. If the wrong password is specified, "random
       data" is returned on read and data is silently ignored on write.

   subkey[0|1|2]/id.hex_pwd
       read-write, binary
       Read or write the subkey id.

       The extension (hex_pwd) is the existing 8-byte password in hexidecimal
       (e.g. password.00020406080A0C0E for bytes 0,2,4,6,8,10,12,14)

       The data portion 8 binary bytes. This is the subkey id.  The correct
       password must be used to write a new id but not to read it.


STANDARD PROPERTIES

       See the file man3/standard.3so.


ALARMS

       None.


DESCRIPTION

       See the file man3/description.3so.

   DS1991
       The DS1991 (3) is an iButton with password protected non-volatile
       memory. Data is read/written with error checking (transparent to the
       user). The memory is divided into 3 different pages with 3 separate
       passwords.

       In theory, choosing an incorrect password is hard to discern because
       the chip responds normally but with incorrect data. There is a
       published analysis suggesting that the "random data" follows a pattern
       and so a concerted attack might be successful.

       The password (in hexidecimal) is used a the file extension
       02.1234123414/subkey0/id.  password allowing a password to be passed to
       the program within the filesystem paradigm.


ADDRESSING

       See the file man3/addressing.3so.


DATASHEET

       http://pdfserv.maxim-ic.com/en/ds/DS1991.pdf


SEE ALSO

       See the file man3/seealso.3so.


AVAILABILITY

       http://www.owfs.org


AUTHOR

       Christian Magnusson (mag@mag.cx) and Paul Alfille

OWFS Manpage                         2003                            DS1991(3)

Search: Section: