From Gen4Wiki

[edit] dc.dat

It appears to be some kind of XML variant with a root element DEVCERT that says lots of stuff about MSDRM (thus, probably related to Plays for Sure.) If you cut off the first two bytes, and read the rest as unicode (2 bytes per char) you get very human readable xml-ish code that is a cert with a lot of signature values, a public key, and some information about your device (manufacturer, distributor, make and model, hardware and firmware version numbers, etc) as well as a url for Microsoft's "secure clock".

This was taken from firmware version 1.5.52, please not some formatting was done for readability, but none of the data was change, only whitespace

<DEVCERT version="1.0">
<CERTIFICATE type="DEVICE">
<DATA>
<UNIQUEID private="1">
                       CZFCP8EGBCBG7C
</UNIQUEID>
<PUBLICKEY Private="1">
                       1C5FddcqzzFLAD9yb6eobtf//YdlWllWJchkXSJFYTm68ISR6QP+EQ==
</PUBLICKEY>
<KEYDATA>
         A64lQpYkBUZjiD9vjeJ01wWOtAY=
</KEYDATA>
</DATA>
<MSDRM_SIGNATURE_VALUE>
                        SfLaOy+ahC6LyCfu5+/OF6aZi3BDEjRrCQ4n947DUp33FSOjr8sTSQ==
</MSDRM_SIGNATURE_VALUE>
<SYMSIGNATURE>
              bMzIGu49GPhQ7ZNFVpVDix9TVlk=
</SYMSIGNATURE>
</CERTIFICATE>
<FALLBACK>
<SECURITYVERSION>
2.4.104.115
</SECURITYVERSION>
<CERTIFICATE  private="1">
    1C5FddcqzzFLAD9yb6eobtf//YdlWllWJchkXSJFYTm68ISR6QP+EQIEaHOz7He10stuTJ/mjAxhrWR1DCoKBIPMwBjpE7/C2pkRKhyuvsRX+3SG
</CERTIFICATE>
</FALLBACK>
<CERTIFICATE  type="GROUP">
<DATA>
<NAME>
A504
</NAME>
   <MANUFACTURER>
                 Archos
   </MANUFACTURER>
   <MAKE>
         A504
   </MAKE>
   <DISTRIBUTOR>
                Archos
   </DISTRIBUTOR>
   <MODEL>
           A504
   </MODEL>
   <SECURITYLEVEL>
                  2000
   </SECURITYLEVEL>
   <HARDWARE_VER_MAJOR>
                       1
   </HARDWARE_VER_MAJOR>
   <HARDWARE_VER_MINOR>
                       0
   </HARDWARE_VER_MINOR>
   <FIRMWARE_VER_MAJOR>
                       1
   </FIRMWARE_VER_MAJOR>
   <FIRMWARE_VER_MINOR>
                       0
   </FIRMWARE_VER_MINOR>
   <FEATURES>
       <CLOCK>
               2
       </CLOCK>
       <SECURECLOCK>
           <URL>
                http://go.microsoft.com/fwlink/?LinkId=25817
           </URL>
           <PUBLICKEY>
                      !CNhvvz1WaNV1AFUmetxkvm9iD4UrE9cnGUi!qcqdxMiXmD1*ikYGA==
           </PUBLICKEY>
       </SECURECLOCK>
       <METERING>
                 1
       </METERING>
       <LICENSE_ACQ>
                    1
       </LICENSE_ACQ>
       <LICENSE_SYNC>
                     1
       </LICENSE_SYNC>
       <ENCRYPTION>
                    1
       </ENCRYPTION>
       <SYMMETRIC_OPT>
                      1
       </SYMMETRIC_OPT>
   </FEATURES>
   <LIMITS>
       <MAXCHAINDEPTH>
                      2
       </MAXCHAINDEPTH>
       <MAXLICENSESIZE>
                       10240
       </MAXLICENSESIZE>
       <MAXHEADERSIZE>
                      5120
       </MAXHEADERSIZE>
   </LIMITS>
<PUBLICKEY>
            7KiDPsl9CZB/GYmnMNp4uy50pTCLEvjNZSrm2QajhPAQPli1ccLhNQ==
</PUBLICKEY>
</DATA>
<MSDRM_SIGNATURE_VALUE>
                       /edeqZJclq5G6KuHDjMjcPU9NHeT9bbFYGCkBn1GQVhc9pKBWqZKaQ==
</MSDRM_SIGNATURE_VALUE>
</CERTIFICATE>
<CERTIFICATE type="AUTHORIZATION">
<DATA>
<SECURITYLEVEL>
               2000
</SECURITYLEVEL>
<AUTH_ID>
          983
</AUTH_ID>
<PUBLICKEY>
            2KqzhyuwjFtjObyu99qx/Z9IYEbxvz+r4Cnui049xqxMHCdPDwYDJg==
</PUBLICKEY>
</DATA>
<MSDRM_SIGNATURE_VALUE>
                       fKmq5LLr+r7rGhA3M4hE8BV8+GLeV7K09RUbofEYTdJ9iI1D2Q7kIw==
</MSDRM_SIGNATURE_VALUE>
</CERTIFICATE>
<CERTIFICATE type="AUTHORIZATION_ROOT">
<DATA>
<AUTH_ID>
          1
</AUTH_ID>
<PUBLICKEY>
            a1t3hxrg!qbOgktnbYaEEi4teCse!gz6RvTPuC!zizKJlpU7xoduSw==
</PUBLICKEY>
</DATA>
<MSDRM_SIGNATURE_VALUE>
                        l5TRtNPfdxdretk8bTlY1XGiaFmaevtJuwErqrwpXL82hScj6cjlDg==
</MSDRM_SIGNATURE_VALUE>
</CERTIFICATE>
</DEVCERT>