With the increasing spread and acceptance of the Internet, it has become necessary to create an electronic equivalent to the manual signature. The term "

electronic signature" is increasingly being used in this context.

An electronic signature is the linking of electronic data with a private (personalized) key. This guarantees the identity of the signer and the integrity of the signed data. These properties are guaranteed by a complex mathematical process.

When exchanging data via anonymous networks (such as the Internet), a situation may arise in which the communication partners involved in an electronic transaction do not know each other. In this case, they cannot be sure that the respective partner is actually the person they claim to be.

Nor is there any guarantee that the data transmitted between the communication partners will arrive at the recipient in the form in which it was sent by the sender. As long as the communication partners do not trust each other, legally binding communication by electronic means is not possible, or only to a very limited extent.

This is where electronic signatures come in. They are the electronic equivalent of a handwritten signature and guarantee the identity of each user. They also enable the secure authentication of all communication partners involved in an electronic transaction.

In addition, electronic signatures can also be used to guarantee the integrity of the transmitted data, as any data manipulation becomes apparent to the communication partners.

Even though the functionality of electronic signatures may appear quite complex, you will not encounter the mathematical processes described below in your daily, operational use of electronic signatures. The complex processes are handled entirely by special software components. The technical process of electronic signatures is based on the use of two different electronic keys (public key concept). Each key pair consists of a private key and a corresponding public key. Although both keys are dependent on each other, they can be used separately. Each individual key pair uniquely identifies an owner. An owner can be a natural person, for example, but also a technical component (e.g., a server) or an email address. The mathematical algorithm developed by Rivest, Shamir, and Adleman (RSA algorithm) used to create the key pair ensures that the private key cannot be calculated even if the corresponding public key is known. The private key can be used to electronically sign electronic content (e.g., an email or an order process). To do this, a special mathematical function (hash function) is used to determine an individual "fingerprint" for the electronic document to be signed. If the content of the document remains unchanged, the hash value calculation always produces the same result. The hash value calculated in this way is encrypted using the sender's private key and then linked to the sender's certificate and the original document. Together, these components form the electronically signed document. The sender's certificate contains, among other things, personal details (name, address, etc.) and their public key. If the recipient wants to verify the signature of an electronically signed document, they need the sender's public key, which is provided with the document. This is used to decrypt the encrypted checksum. A hash value is then calculated again from the original electronic document. The two hash values are then compared. If they do not match, the document has definitely been altered (e.g., by manipulation by third parties during transport). The RSA method is currently considered secure. So far, there is only one theoretical possibility of calculating a private key from a public key and thus circumventing the procedure. However, even if the computing power of all computer systems available worldwide were combined, it would take several years to calculate a single private key. Keys with a length of 2048 bits, which are used regularly, are currently common and secure.

Electronic signatures have two important properties: firstly, they verify the identity of the signatory and, secondly, they ensure the integrity of the electronic data transmitted between the sender and recipient. When you receive electronically signed data,

you can therefore be sure that your communication partner is actually who they claim to be and that the data transmitted between you and your communication partner has not been altered on its way through the Internet. Any change, no matter how small, is detected by the underlying technical process and immediately visible to the recipient.

These characteristics make electronic signatures the technical basis for secure and legally binding electronic transactions. A qualified electronic signature therefore has the same legally binding effect in legal transactions as your handwritten signature. At the same time, electronic signatures are much more accurate and forgery-proof than manual signatures.

Electronic encryption ensures the confidentiality of the transmitted data. It ensures that the transmitted data can only be viewed by the intended communication partners.

To illustrate the very limited security of unencrypted email transmission, a comparison with normal postal delivery is presented below. In this case, an email would have roughly the same security features as a postcard written in pencil: it can be read and manipulated by anyone on its way from the sender to the recipient. Manipulation

can refer to changes to the sender's name, changes to the actual email content, or even any attachments (Word documents, presentations, etc.). The real danger is that neither the sender nor the recipient of the email will even notice any manipulation. Furthermore, due to their digital nature, such manipulations cannot be detected and the risk of being discovered as the perpetrator is extremely low. This shortcoming can

also be remedied with the help of electronic encryption. The electronic signature, which secures the identity of the communication partners and the integrity of the transmitted data, forms the basis for electronic communication. In combination with electronic encryption to ensure the confidentiality of the transmitted data, it also enables highly secure electronic communication.

The possible applications of electronic encryption are diverse and depend on the personal security requirements of each individual.

One important application scenario, for example, is securing electronic communication via email. In private and especially in professional environments, emails with sensitive content are sent from time to time, and the information they contain should not fall into the hands of unauthorized persons. Electronic encryption provides a solution here, as it ensures that the contents of the email are only visible to those for whom the information is intended.

Another possible application is to encrypt certain files or even entire directories on the hard drive to prevent confidential information from falling into the wrong hands.

Similar to electronic signatures, electronic encryption is also based on a complex mathematical process. It is a hybrid process, i.e., a combination of asymmetric and symmetric encryption methods.

The hybrid process combines the speed advantages of symmetric methods with the flexibility of asymmetric methods. The encryption process involves several steps. In the first step, a "session key" is generated. As the name suggests, this is a one-time key that is used for a single encryption process. The electronic data is then encrypted with the session key.

In order to securely transmit the session key together with the encrypted data, it is encrypted in the next step using the recipient's public key according to an asymmetric procedure. The encrypted data can then be transmitted electronically.

The recipient of an encrypted message first decrypts the session key with their private key. The decrypted session key can then be used to decrypt the data. Here,

too, you will not notice much of the details of encryption and decryption in everyday use. The complex processes are handled entirely by special software components.

Electronic encryption allows you to transfer confidential information electronically while being sure that this information cannot be viewed by unauthorized third parties.

In combination with electronic signatures, electronic encryption offers maximum protection and security when transferring electronic data and communicating electronically.