Content-type: text/html Manpage of ppddcsum

ppddcsum

Section: User Commands (1)
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NAME

ppddcsum - generates or checks a ppdd checksum  

SYNOPSIS

This program allows you to use checksums to protect the data on a ppdd device from tampering. It can generate checksums on existing data and can check an existing checksum.  

DESCRIPTION

The program works by reading all the data and generating an md5 hash and then comparing this with an already existing md5 hash in the first 1024 bytes of the file (where it is protected by the key derived from the pass phrase). The user can choose to check both the cipher and plain text hashes. Normally the ciphertext hash is adequate and is much quicker.  

The program normally operates on the file (or device) while it is not in use by ppdd (i.e. before a ppddsetup -s or after a ppddsetup -d). However in the case of root filesystem encryption it has to operate on the ppdd device even while the filesystem is mounted. This special feature is invoked by a -r switch and it should not be used for any other purpose.  

OPTIONS

If any invalid combination of switches and arguments is used the program displays a primitive help message. The number of arguments depends on the switches used  

Generating checksums

ppddcsum -g file_or_device
ppddcsum -gp file_or_device  

Checking checksums

ppddcsum file_or_device
ppddcsum -p file_or_device  

Generating root filesystem checksum

ppddcsum -gr ppdd_device  

Checking root filesystem checksum

ppddcsum -r ppdd_device  

-g means generate -p means plaintext checksum -r means root filesystem  

RETURN VALUE

The program returns 0 if everything worked as expected.
The program returns 1 if anything has gone wrong.
 

ERRORS

All ppdd utilities display fairly meaningful errors (mostly on stderr). In all cases the errors have a unique error number to help locate the problem in the source code. If an error message is not clear then best source of explanation at this stage is the source itself.  

ENVIRONMENT

The program does not use any environment variables.  

FILES

Files (and devices) are specified as arguments.  

SEE ALSO

ppdd(1) ppdddown(1) ppddinit(1) ppddmchk(1) ppddpassw(1) ppddsetup(1) ppdduprev(1) ppdecrypt(1) ppdncrypt(1) ppddtab(5).  

(c) 1999 Allan Latham - version 0.9

 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
Generating checksums
Checking checksums
Generating root filesystem checksum
Checking root filesystem checksum
RETURN VALUE
ERRORS
ENVIRONMENT
FILES
SEE ALSO
This document was created by man2html, using the manual pages.
Time: 16:35:26 GMT, September 14, 1999