RSA-Verifier

The RSA-Verifier offers a comprehensive solution for checking the validity of and exporting the signatures of a document. The tool is used to load a PDF document and corresponding keys so that the signatures can be checked and exported in various formats.

The strict separation of the decryption, evaluation and analysis processes between the export application (signotec RSA-Verifier) and the analysis tool (signotec eSig-Analyze) enables secrecy with regard to the private key.

Licensing

When the program is started up for the first time, a valid license key must be entered. Once the license has been activated successfully, the RSA-Verifier opens.

You will generally receive the license along with the invoice following purchase.

Operation

The following section describes the functions and operation of the software.

Load PDF document

The button “Load PDF document...” is used to open a PDF document. When it is opened, the document is displayed in the RSA-Verifier.

Load RSA key file

To enable the signature data to be checked, visualized and exported, the data must first be decrypted.

The button “Load RSA key file...” is used to load the private key to decrypt the signatures.

The key must be a file in P12, PFX or PEM format. Alternatively, the key can be selected from the Windows certificate store. If the key is password-protected, the password must also be entered. If not, the password field can be left empty.

The private key must match the document. As standard, signotec products generally use a key with a private section that is stored at a notary’s office Even signotec does not have access to this private key, so only the notary is able to decrypt the signatures.

Display signature data

This button is used to display and analyze the biometric data for the signatures that the document contains.

To enable use of this function, a document must be open and the corresponding private key must be loaded. If no document is open, the button is deactivated. If a document is open, but no private key is loaded, the dialog for loading a key is displayed initially.

If a document is open and the corresponding private key is loaded, the signature data is displayed in a new window.

Click “Next” to display the next signature. Clicking “Cancel” closes the window.

Signature data

The following information relating to the signature is displayed:

• Version: Information on the signature handler used.

• Timestamp: Timestamp for when the signature was inserted into the document.

• Pad type: Specifies which signature device was used for the signature.

• User: Name of the logged-in user who inserted the signature.

• PC: Name of the computer used for the signature capture.

• PadID: Serial number of the signature device that was used.

Render signature

Clicking the arrow icon (>) next to the signature renders the process of generating the signature (travel, speed, etc.) in the form of an animation.

Display biometric data

The button “Display biometric graphic for this signature” is used to display the biometric data for the provided signature.

The biometric data is displayed in various graphs providing information on pressure pattern P(t), speed V(Pts) / speed V(t), increase in speed A(pts) / increase in speed A(t) and travel X(t) / travel Y(t).

Click the “Print…” button to print the graph. Clicking the “Close” button closes the window.

RSA Pad Security

The button “RSA Pad Security” is only displayed if the biometric data was encrypted within a signotec signature pad by means of the RSA functions. The function provides additional security-related information relating to the signature.

Security check

This function checks in particular the integrity of the biometric data and verifies that the signature was captured for this specific document. It is also checked whether the hash value of the original document encrypted in the signature matches that of the current document. If this is found not to be the case, a warning is issued.

This signotec procedure is patent-protected and is one of the signotec signature pad’s key security features.

Information on the RSA scheme and the hash algorithm used is also displayed.

If the document was signed with “content signing,” the SHA256 checksum is also displayed, which can be compared manually with the displayed image.

Properties of the signature device

Under “Properties of the signature device,” information on the signature pad used is displayed again.

• Serial number: The serial number makes it possible to unambiguously identify the signature pad used.

• Firmware: Contains the firmware version of the signature pad used.

• Origin of the signature key: Contains information as to whether the certificate used for the digital signature was created in the signature pad or externally.

• Device options: Contains information on the state and the configuration of the signature pad. Deviations from the factory state are displayed here.

Time of start of signature

This timestamp specifies when the signature capture for this signature was started.

This is always determined on the basis of the time of the system on which the software was run that communicated with the signature pad and captured the signature. The timestamp is always based on the “UTC” time zone.

Check document integrity

The button “Check document integrity…” is used to check whether the signatures in the document are valid.

The validity is checked for each signature separately. The information (name, reason, timestamp) for the individual signature field is displayed.

After each check, it can be decided whether the check should be continued for the next signature field or terminated.

If the document was signed with “content signing,” as mentioned in the section on “RSA Pad Security,” the SHA checksum is displayed so that the depicted value can be checked manually against the value in the signed image.

Export signature data

The button “Export signature data” can be used to export the signatures in the document to any directory as individual files.

Each signature is exported in three formats:

• signotec format (*.sdb)

• RAW format (*.csv)

• ISO format (*.iso)

The exported data can be used for further analysis, e.g. in eSig-Analyze.