gdcmanon - Man Page

  -e --de-identify            De-identify DICOM (default)
  -d --re-identify            Re-identify DICOM
     --dumb                   Dumb mode anonymizer

Warning when operating in dumb mode, you need to also specify an operation to do, such as 'remove' or 'empty' a tag, see below the dumb mode options.

  -i --input                  DICOM filename / directory
  -o --output                 DICOM filename / directory
  -r --recursive              recursively process (sub-)directories.
     --continue               Do not stop when file found is not DICOM.
     --root-uid               Root UID.
     --resources-path         Resources path.
  -k --key                    Path to RSA Private Key.
  -c --certificate            Path to Certificate.
  -p --password               Encryption passphrase.

     --crypto=
           openssl            OpenSSL (default on non-Windows systems).
           capi               Microsoft CryptoAPI (default on Windows systems).
           openssl-p7         Old OpenSSL implementation.

     --des            DES.
     --des3           Triple DES.
     --aes128         AES 128.
     --aes192         AES 192.
     --aes256         AES 256.

     --empty   %d,%d           DICOM tag(s) to empty
               %d,%d,%s        DICOM private tag(s) to empty
     --clear   %d,%d           DICOM tag(s) to clear
               %d,%d,%s        DICOM private tag(s) to clear
     --remove  %d,%d           DICOM tag(s) to remove
               %d,%d,%s        DICOM private tag(s) to remove
     --replace %d,%d=%s        DICOM tag(s) to replace
               %d,%d,%s=%s     DICOM private tag(s) to replace

  -h   --help
         print this help text and exit

  -v   --version
         print version information and exit

  -V   --verbose
         verbose mode (warning+error).

  -W   --warning
         warning mode, print warning information

  -E   --error
         error mode, print error information

  -D   --debug
         debug mode, print debug information

  GDCM_ROOT_UID Root UID
  GDCM_RESOURCES_PATH path pointing to resources files (Part3.xml, ...)

The only thing required for this operation is a certificate file (in PEM format).

$ gdcmanon --certificate certificate.pem -e original.dcm original_anonymized.dcm

You can use –asn1 option from gdcmdump to dump the generated DataSet as ASN1 structure (see gdcmdump(1) for example).

The only thing required for this operation is a private key (in PEM format). It is required that the private key used for the re-identification process, was the actual private key used to generate the certificate file (certificate.pem) used during the de-identification step.

$ gdcmanon --key privatekey.pem -d original_anonymized.dcm original_copy.dcm

You can then check that original.dcm and original_copy.dcm are identical.

It is very important to understand the following refsection, when anonymizing more than one single file. When anonymizing multiple DICOM files, you are required to use the directory input. You cannot call multiple time the gdcmanon command line tool. Indeed the tool stores in memory during the process only a hash table of conversion so that each time a particular value is found it get always replaced by the same de-identified value (think: consistent Series Instance UID).

This functionality is not described in the DICOM standard. Users are advised that improper use of that mode is not recommended, meaning that important tag can be emptied/removed/replaced resulting in illegal/invalid DICOM file. Only use when you know what you are doing. If you delete a Type 1 attribute, chance is that your DICOM file will be not accepted in most DICOM third party viewer. Unfortunately this is often this mode that is implemented in popular DICOM Viewer, always prefer what the DICOM standard describes, and avoid the dumb mode.

The following example shows how to use dumb mode and achieve 5 operations at the same time:

• Empty the tag (0010,0010) Patient's Name,
• Clear the tag (0010,0020) Patient ID,
• Remove the tag (0010,0040) Patient's Sex
• Remove the tag (0010,1010) Patient's Age
• Replace the tag (0010,1030) Patient's Weight with the value '10'

You are required to check which DICOM attribute is Type 1 and Type 1C, before trying to 'Empty','Clear' or 'Remove' a particular DICOM attribute. For the same reason, you are required to check what are valid value in a replace operation.

$ gdcmanon --dumb --empty 10,10 --clear 10,20 --remove 10,40 --remove 10,1010 --replace 10,1030,10 012345.002.050.dcm out.dcm

In the following example a private tag (0029,20,SIEMENS MEDCOM HEADER) is cleared out (made empty only when present):

$ gdcmanon --dumb --clear "0029,20,SIEMENS MEDCOM HEADER" input.dcm output.dcm

Multiple operation of –dumb mode can take place, just reuse the output of the previous operation. Always use gdcmdump on the input and output file to check what was actually achieved. You can use a diff program to check only what changed (see gdcmdiff(1) for example).

Irreversible Anonymization

$ gdcmanon -c certificate.pem input.dcm anonymized_reversible.dcm

$ gdcmanon --dumb --remove 400,500 --remove 12,62 --remove 12,63 anonymized_reversible.dcm anonymized_irreversible.dcm

$ gdcmanon input.dcm anonymized_irreversible.dcm

$ gdcmanon -e input.dcm anonymized_irreversible.dcm

Command line to generate a rsa key (512bit)

$ openssl genrsa -out CA_key.pem

Command line to generate a rsa key (2048bit)

$ openssl genrsa -out CA_key.pem 2048

Command line to generate a rsa key (2048bit) + passphrase

$ openssl genrsa -des3 -out CA_key.pem 2048

From your previously generated Private Key, you can now generate a certificate in PEM (DER format is currently not supported).

$ openssl req -new -key CA_key.pem -x509 -days 365 -out CA_cert.cer