DigiDoc3 client displays signature as not valid - Error 166: ERROR 166 Invalid signature value! Missing or wrong asn.1 signature structure

Since version 3.7 of the ID-card software the signature may be displayed as invalid in the DigiDoc3 client and the following error message is visible under the “See details" section: ERROR 166 Invalid signature value! Missing or wrong asn.1 signature structure

This is a defective digitally signed container and the signature is not valid.

  • If you have received such a file then let the sender know that the file was defective.
  • If you are the author of such a file then update your ID-card software on the installer.id.ee website and recreate the digitally signed file.

Earlier versions of the DigiDoc3 client, the SK Digidoc Client or other environments providing the signature verification functionality may erroneously declare the signature valid. In any case the digitally signed container is defective and the signature is not valid.

Several significant security improvements were made in version 3.7 of the software, affecting the verification of signatures. Additional validations have been added, that verify the  cryptographical integrity of the signature.

A known source for these faulty digitally signed containers is old ID-card software for Mac OSX 10.4 and 10.5, which was available between 2008-2010.

Instructions of how to identify faulty software can be found here.


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