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dcmsign

NAME

dcmsign - Sign and Verify DICOM Files

SYNOPSIS

 
 dcmsign [options] dcmfile-in [dcmfile-out]
 

DESCRIPTION

The dcmsign utility reads a DICOM file (dicomfile-in), performs a digital signature operation and, if any modification has taken place, writes the DICOM object to an output file (dicomfile-out).

Five digital signature operations are supported:

•

verification of all signatures in the DICOM file

•

creation of a new digital signature located in the main dataset,

•

creation of a new digital signature in an item of a sequence embedded within the dataset,

•

removal of a single digital signature from the DICOM file, and

•

removal of all digital signatures from the DICOM file.

PARAMETERS

 
 dcmfile-in   DICOM input filename to be processed
 
 dcmfile-out  DICOM output filename
 

OPTIONS

general options

 
   -h    --help
           print this help text and exit
 
         --version
           print version information and exit
 
   -v    --verbose
           verbose mode, print processing details
 
   -d    --debug
           debug mode, print debug information
 
   +d    --dump  [f]ilename: string
           dump byte stream fed into the MAC codec to file
           (only with --sign or --sign-item)
 
 

input options

 
 input file format:
 
   +f    --read-file
           read file format or data set (default)
 
   +fo   --read-file-only
           read file format only
 
   -f    --read-dataset
           read data set without file meta information
 
 input transfer syntax:
 
   -t=   --read-xfer-auto
           use TS recognition (default)
 
   -td   --read-xfer-detect
           ignore TS specified in the file meta header
 
   -te   --read-xfer-little
           read with explicit VR little endian TS
 
   -tb   --read-xfer-big
           read with explicit VR big endian TS
 
   -ti   --read-xfer-implicit
           read with implicit VR little endian TS
 

signature commands

 
         --verify
           verify all signatures (default)
 
   +s    --sign  private key file, certificate file: string
           create signature in main object
 
   +si   --sign-item  keyfile, certfile, item location: string
           create signature in sequence item
 
   +r    --remove  signature UID: string
           remove signature
 
   +ra   --remove-all
           remove all signatures from data set
 

signature creation options (only with --sign or --sign-item):

 
 private key password options:
 
   +ps   --std-passwd
           prompt user to type password on stdin (default)
 
   +pw   --use-passwd  [p]assword: string
           use specified password
 
   -pw   --null-passwd
           use empty string as password
 
 key and certificate file format options:
 
   -pem  --pem-keys
           read keys/certificates as PEM file (default)
 
   -der  --der-keys
           read keys/certificates as DER file
 
 digital signature profile options:
 
   -pf   --profile-none
           don't enforce any signature profile (default)
 
   +pb   --profile-base
           enforce base RSA signature profile
 
   +pc   --profile-creator
           enforce creator RSA signature profile
 
   +pa   --profile-auth
           enforce authorization signature profile
 
 MAC algorithm options:
 
   +mr   --mac-ripemd160
           use RIPEMD 160 (default)
 
   +ms   --mac-sha1
           use SHA-1
 
   +mm   --mac-md5
           use MD 5
 
 tag selection options:
 
   -t    --tag
           tag: "xxxx,xxxx" or a data dictionary name
           sign only specified tag
           this option can be specified multiple times
 
   -tf   --tag-file  filename: string
           read list of tags from text file
 
 signature format options:
 
   -fn   --format-new
           use correct DICOM signature format (default)
 
   -fo   --format-old
           use old (pre-3.5.4) DCMTK signature format, non-conformant
           if signature includes compressed pixel data
 
 

output options

 
 output transfer syntax:
 
   +t=   --write-xfer-same
           write with same TS as input (default)
 
   +te   --write-xfer-little
           write with explicit VR little endian TS
 
   +tb   --write-xfer-big
           write with explicit VR big endian TS
 
   +ti   --write-xfer-implicit
           write with implicit VR little endian TS
 
 length encoding in sequences and items:
 
   +e    --length-explicit
           write with explicit lengths (default)
 
   -e    --length-undefined
           write with undefined lengths
 

NOTES

Files and Parameters

The dcmsign utility reads and writes a number of files and file formats which are described in this section.

Public Key Certificates are expected in X.509v3 format, either with PEM or DER encoding. The dcmsign utility currently supports RSA and DSA public keys, although only RSA keys are defines in the Security Profiles of the DICOM standard.

Private Keys are expected in PEM or DER encoding. PEM is recommended (and default) because this allows to keep private keys in encrypted form. Command line options control the behaviour of dcmsign when an encrypted PEM key is opened (see above). In general it is not recommended to specify the encryption password in the command line because the command line may be visible to other processes in the system, e.g. 'ps -ef'.

The list of data elements to sign can either be read from a file or specified on the command line or both (in this case the keys are combined).

On the command line, attribute keys are specified as

 
 --tag "gggg,eeee"  where gggg and eeee are the hexadecimal group
                    and element numbers
 --tag "Name"       where 'Name' is a symbolic attribute name from
                    the DICOM dictionary (see below).
 

When attribute tags are read from file with the --tag-file option, a plain text file of max. 64 kbyte is expected. Tags within the file are either symbolic names from the data dictionary or have the format (gggg,eeee) (with braces). Tags are separated by one or more whitespace characters.

The --sign-item operation requires a location string that describes in which sequence item a signature is to be created. The location string has the following format:

 
 SequenceName[index].SequenceName[index].SequenceName[index](...)
 

where SequenceName is either a symbolic attribute name from the data dictionary or a numeric tag in the format (gggg,eeee) and index is an unsigned decimal integer for the item number, starting with zero for the first item in a sequence. As an example, the following location string

 
 ReferencedSeriesSequence[0].ReferencedImageSequence[1]
 

would cause a digital signature to be created in the second item of the ReferencedImageSequence (0008,1140) which is located in the first item of the ReferencedSeriesSequence (0008,1115) which is located in the main DICOM dataset.

COMMAND LINE

All command line tools use the following notation for parameters: square brackets enclose optional values (0-1), three trailing dots indicate that multiple values are allowed (1-n), a combination of both means 0 to n values.

Command line options are distinguished from parameters by a leading '+' or '-' sign, respectively. Usually, order and position of command line options are arbitrary (i.e. they can appear anywhere). However, if options are mutually exclusive the rightmost appearance is used. This behaviour conforms to the standard evaluation rules of common Unix shells.

In addition, one or more command files can be specified using an '@' sign as a prefix to the filename (e.g. @command.txt). Such a command argument is replaced by the content of the corresponding text file (multiple whitespaces are treated as a single separator) prior to any further evaluation. Please note that a command file cannot contain another command file. This simple but effective approach allows to summarize common combinations of options/parameters and avoids longish and confusing command lines (an example is provided in file share/data/dumppat.txt).

ENVIRONMENT

The dcmsign utility will attempt to load DICOM data dictionaries specified in the DCMDICTPATH environment variable. By default, i.e. if the DCMDICTPATH environment variable is not set, the file <PREFIX>/lib/dicom.dic will be loaded unless the dictionary is built into the application (default for Windows).

The default behaviour should be preferred and the DCMDICTPATH environment variable only used when alternative data dictionaries are required. The DCMDICTPATH environment variable has the same format as the Unix shell PATH variable in that a colon (':') separates entries. The data dictionary code will attempt to load each file specified in the DCMDICTPATH environment variable. It is an error if no data dictionary can be loaded.

COPYRIGHT

Copyright (C) 2000-2005 by Kuratorium OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany.