How to get access to biometric information in a digitized signature


EADTrust provides Secret Key Escrow Services for biometric, digitized or graphometric electronic signatures in several specialized platforms.

The fact of the existence of this custody implies that the institution using the platforms adopts measures in order to guarantee that the biometric information is ciphered (with the public key) and included in the signed electronic documents, in a way  that ensures that this information is not freely available for the entity that uses the platform, and, therefore, cannot use it to associate it to any other document.

Thus, both the entity promoting the digitized signature system that makes use of the platform and the signers themselves are in equal conditions to exercise the right to proof  if any signature belongs to a certain person. To verify if any digitized signature is associated to a certain person, the litigants hire the services of a forensic document examiner that compares signatures (or other forensic computer expert analisys report  assisted by a biometric forensic analysis software).

The process begins with the suspected PDF file that includes the controversial signature, so this file must be easily available for the entity and for the signer. It will be required to identify the Compliance Officer, Data Privacy Officer, Litigation Support or Computer Security departments in the company who know about the case and can get the file or files in which are included the questioned  signature, and request the file through the appropriate channels.


It is highly recommended to analyze the convenience of a litigation or if, on the contrary, it would be better to make any check or negotiation just in case the litigation can be avoided. Once the PDF file that includes the biometric signature is available, it is possible to carry out the following steps:

  • Prepare a mandate or a Power of Attorney of a person with legal powers within the organization, appointing the person of the entity or the expert (or document examiner) so that he/she can reach out the Trust Service Provider that custodies the private keys (EADTrust) on behalf of the organization. Likewise, if the signatory himself is the interested party he may appoint a representative, a mandatary or an expert to contact the Trust Service Provider.
  • Make a copy of the Power of Attorney and of the cititzen ID card (or any other foto ID card) of the proxy.
  • Prepare a submission in letter format that briefly describes the problem and that requests the intervention of the entity that holds the private keys (EADTrust) including the identification data of the person who will contact the entity. It is usually signed by the proxy.
  • Those who reach the entity that cutodies the private keys (EADTrust), usually do it in person or through an agreed secure digital communications procedure.
  • It is important to verify that the entity that custodies the private keys (EADtrust) holds the latest version of the software delivered by the platform developers to decrypt the biometric information using the PDF document.
  • The entity that custodies the private keys (EAD Trust) never delivers them. It makes use of the key to decrypt the document and extract the biometry that is delivered to the applicant, but the private keys do not leave its custody.

Once the biometry is decrypted, adequate specimen of known signatures is also needed. If the evidence will be presented in court, the expert’s request is described in the Statement of Claim or in the Statement of Defence, so that in due course, the specimen of known signatures are made in presence of the pertinent Chief Court Clerk or Court officer.

If it is desired to carry out the comparative annalisys of signatures with the help of the document examiner, without proceeding with a litigation, the signer has to be contacted to create several signatures (5 or 10, as many as the expert witness recommends) in a digitizer tablet similar to the one used originally to sign, with the support of the forensic software for expert’s use.

It is possible to contact EADTrust, on the telephone +34 91 7160555 (or 902 365 612 from Spain) where they will guide you more precisely according to the entity that has managed the signatures in the PDF documents of your interest.

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