Since documents created in ABRA Flexi can be sent electronically, the application must be able to:

An electronic signature represents the electronic identification of the author (sender) of an electronic document, attached to that document.

Just as a handwritten signature can be verified, electronic signatures can also be verified. This function is provided by certification authorities. In the Czech Republic, one such authority is Česká pošta (Czech Post). A certification authority issues certificates, guarantees the identity of their holder, and verifies the accuracy of the stated information.

For electronic signatures to work, two types of keys are always generated.

The public key can be thought of as a company key, although it may also belong to a single individual.

The owner makes it freely available, and anyone who has access to this key can use it to decrypt messages intended for them.

Every user must keep their private key secret.

It is this private key that is used to encrypt messages, and it can be used to trace the true owner of an electronic signature. It can be compared to a national ID card.

Both keys are mathematically linked. They can be thought of as two very large numbers.

For encryption to be effective, there must be no known method by which the private key could be calculated from the public key — even using highly powerful computers.

For practical reasons, instead of encrypting the entire document, only its hash is encrypted — a kind of digital equivalent of a document's fingerprint.

The algorithms used to generate a hash for encryption purposes make it virtually impossible to modify a document without also changing its hash.

This makes this method of electronic signing highly secure.

This is a list of electronic signature certificates that can be used to sign documents sent by email.

You can open this list from the menu:

Tools → Certificates

The data in this table is filled in automatically when a new certificate is created.

At the same time, the personal certificate is saved to the list at:

Tools → Company Users → specific user → Certificates tab

The toolbar at the top of the table contains a number of buttons, the functions of which are described in the dedicated chapter Using the Application.

Clicking the "New" button launches the "New Certificate Wizard", which guides the user through adding their electronic signature certificate.

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Clicking the New button launches the certificate creation wizard.

This wizard allows you to add an electronic signature.

The user must choose where the certificate will be stored.

Along with the private certificate, the public certificate is automatically saved as well.

The certificate will be stored on the server together with your data and will be included in backups.

It will also be stored in a secure vault and protected by the password you use to log in to ABRA Flexi.

This allows you to securely access the certificate from any computer connected to the internet. Likewise, anyone you share your password with will also be able to access it.

Steps:

A new record will be saved to the table:

With this option, the certificate remains stored on your computer and will only be accessible when working on that specific device.

The following will be saved to the table:

Each time a document is signed, the certificate will be reloaded from your computer.

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If you have a certificate for signing an exported document and wish to send the document electronically, after confirming the sending method you will be prompted to select the appropriate certificate.

Once selected, the following actions will take place:

A prepared email message with the attached document will then be presented for sending. The document is created:

You can then review or update the recipient's email address and send the message.

If you have a certificate for signing an exported document and wish to send the document electronically, after confirming the sending method you will again be prompted to select a certificate.

Once selected, a dialog will appear where you can specify where you want to save the signed document.

After that, it is up to you how you deliver the document, for example:

For each company in your address book, you can store certificates in a dedicated tab. These certificates are used to verify electronic signatures on documents received by email from that company.

The data in this tab is filled in automatically upon completion of the partner electronic signature import process.

Clicking the New button opens the dialog:

Add Certificate to Address Book

Use this dialog to import a partner's electronic signature certificate.

The certificate will be saved to the given company and the system will be able to verify signatures on documents from this partner.

When the document is opened, it will be displayed.

Clicking the Signature Panel button in the upper right area of the document will open or close the left side of the document, where you can read more detailed information about the validity of the signature.

If the sender has, for example:

the following message will appear at the top of the document:

At least one signature has issues.

Clicking the Validate All button on the left side allows you to verify the signatures.

Opening the invoice launches the ABRA Flexi application.

After logging in to the company into which the received invoice is to be imported, a dialog for importing an invoice from the ISDOC electronic format will appear, showing the basic invoice details:

If the sender has, for example, an invalid certificate or has not sent you their public certificate, the following message will appear in the dialog:

The document was signed by an unknown authority.

If the details are correct and you trust the given signature, select:

Then confirm the dialog by clicking Next.

The invoice will then be imported into your accounting records. You will be notified of completion by a separate message.

It depends on your working style:

2. What does the message "The document was signed by an unknown authority" mean?
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This typically means that the sender has an invalid certificate or has not sent you their public certificate.