How can i add a new signature with PKCS1?

Question

The default sign method of Acrobat is PKCS7,how to change to PKCS1?
Thanks!

Answer 1

Hi,
There are two different tacks you could take here. One way is to set a Seed Value that works on a per signature field basis and the other is to make a change to the registry that works on a general basis. Of course, a change to the registry it's on a per computer basis where as Seed Value, because it's on a per document basis will travel from computer to computer.
If you want to set the Seed Value it's done via JavaScript. Go to http://livedocs.adobe.com/acrobat_sdk/9/Acrobat9_HTMLHelp/wwhelp/wwhimpl/js/html/wwhelp.ht m?href=JS_API_AcroJS.88.1.html#1515776&accessible=true and click the Search button and look for "Seed Value". When it returns, click on "signatrueSetSeedValue" and then scroll down to Example 2 to see how to set the subFilter. You're going to want to use the value adbe.x509.rsa_sha1 as opposed to what is shown in the example.
If you would rather make the change global to the computer then you need to modify the registry (Windows) or plist (Mac). I'll give you an example for Windows, but if you need help with the Mac let me know. Run regedit and then go to HKEY_CURRENT_USER\Software\Adobe\Adobe Acrobat\9.0\Security\cPubSec with the following caveats. First, if you are using Reader, as opposed to Acrobat, change \Adobe Acrobat\ to \Acrobat Reader\. The other thing is, if you are using an earlier version of Acrobat change "9.0" to the major version number you are currently running. Even if you were using version 8.1 you would still look for 8.0.
Now that you've navigated to the correct location add the Binary Value "aSignFormat" (without the quotes). Next, edit the value and click into the right side of the dialog and add the same plain text string noted above for use with Seed Value. Please see the attached screen shot (click on the link below to open the picture and then click on the black X to close it). An important thing to note here is the string needs to be NULL terminated. After you've type the plain text string into the right side of the dialog, click into the end on the hex string at the left side and type a zero. You'll note that it adds what appears to be a dot at the end of the plain text string on the right, but it's not really a dot.
I hope this helps,
Steve