Crypto Academy

What is a cryptographic key?

What is a cryptographic key?

Would you like to know what is a cryptographic key? Discover what types there are and what they are used for.

Public and Private keys

What is a cryptographic key?

In this article we will  give you an answer to what is the cryptographic key. A cryptographic key is a special set of data that is used to encrypt and decrypt information sent over the network. Cryptographic keys are used for encrypting and decoding messages, for setting and verifying digital signatures or for verifying message authenticity, etc. The success of decryption largely depends on the key used. If for any reason access to it is lost, it will be impossible to decrypt the data.

Important to note that the key reliability is determined by the so-called key length, which is measured in bits. Length is an important parameter of cryptographic strength in modern encryption algorithms. The standard key length is 128 or 256 bits. Besides, cryptographic keys differ according to the algorithms of the system. There are 2 main types of keys: Open (public) and Closed (private). Let’s take a look at them.

Public key

The public key is available to everyone. It’s used for encrypting data when the browser accesses the server.

In public-key systems, each person has both public and private keys that are mutually complementary. The public key is available since it is the key to transmit information in the network. This key can be published in the public domain to verify the electronic digital signature and to prevent malicious actions on the part of the document certifier if he refuses to sign it.

Private (secret key)

First of all, the private key is known only to the site owner. It’s used for decrypting data sent by the browser. In order to guarantee the complete confidentiality and security of the data and protect it from intruders, the private key must be kept secret by its owner from third parties. As you know, the private key is always protected by a password, which prevents unauthorized use. Encryption with two keys of different types guarantees the safety of information. Even if the fraudster intercepts the traffic, he will not be able to decrypt it without the private key. The private key is generated by the system in a random sequence of numbers and letters. It is worth noting that only a certain version of the public key is suitable for one private key. 

How public and private keys work.

A public key can seem difficult for a newbie though very useful for communication especially when the sender will not want everyone to know the content of the message. In cryptography two individuals namely the sender and the receiver are involved and both have a public and a private key that contains large mathematical properties. If a message is encoded using someone’s public key, he in turn will be able to decode it using his private key. Simply put, within the public key infrastructure, the public key encrypts data and as soon as that has been done, only the person with the private key will be able to decode its content. The length of a public key depends on the algorithm it is made with and it varies from 128 bits to 4096 bits. 

A private key on the other hand which is a secret key is only known by its owner. It is a long randomly generated number that cannot be guessed. It can only be decoded by the person to whom the message is directed. For example, Peter sends an encrypted message to Nadia and somehow forgets to provide her with the secret key. Without it, Nadia will be unable to get the message and if eventually she is provided with the private key, then will she be able to get the message. Generally, a private key is kept safely so that no third party or fraudster will be able to access it. 

In addition, both keys are stored in a file known as a key ring, which also stores various key certificates. There is usually a ring for public keys and a ring for private keys. In general, public and private key encryption can be considered as a case for which two keys are used: one can only close, the other can open. But, although the private and public keys are mathematically related, it is not possible to calculate the private key from the public one.

However, we can be sure that the keys provide security for the system. They exclude the possibility of information leakage, as well as the possibility of redirecting it to another site.