In cryptography, a key memorandum of understanding is a protocol in which two or more parties can agree on a key in such a way that both influence the outcome. If properly implemented, it prevents unwanted third parties from imposing an important choice on the parties. Protocols that are useful in practice also do not reveal to any wiretapped party which key has been agreed. A large number of cryptographic authentication schemes and protocols have been developed to provide key authenticated agreements to prevent man-in-the-middle and related attacks. These methods mathematically link the agreed key to other agreed data, such as.B. password-certified key convention algorithms can perform a cryptographic exchange of keys using a user`s password knowledge. The first publicly known public key memorandum of understanding that meets the above criteria was the Diffie-Hellman key exchange, in which two parties together expose a random generator in such a way that a listener cannot determine in a feasible way what is the resulting value used to make a common key. Authenticated key protocols require the separate setting of a password (which can be smaller than a key) in a way that is both private and integrity. These are designed to withstand man-in-the-middle attacks and other active attacks against the password and established keys. For example, DH-EKE, SPEKE, and SRP are authenticated variations of Diffie-Hellman. The exponential exchange of keys in itself does not provide for prior agreement or subsequent authentication between participants. It has therefore been described as an anonymous key memorandum of understanding. Frequently used key-agreement protocols include Diffie-Hellman or rsa- or ECC-based protocols.
The initial and still most famous protocol of the key agreement was proposed by Diffie and Hellman (see the key agreement Diffie Hellman) as well as their concept of public key cryptography. In principle, users send the Alice and Bob Public Key values through an uncertain channel. Based on the knowledge of their corresponding private keys, they are able to calculate a common key value correctly and securely. However, an earpiece is not able to calculate this key in the same way by simply knowing the. A key memorandum of understanding is usually called after two parties have been authenticated. The agreement on a common key allows the parties to communicate securely via unreliable communication networks. The key agreement is a form of key exchange (see also the encryption key) in which two or more users execute a protocol to securely share a resulting key value. A key transport protocol can be used as an alternative to the key agreement. The distinguishing feature of a key MOU is that participating users each contribute an equal share to the calculation of the resulting common key value (unlike a user who distributes a key value to other users).
Many key exchange systems allow one party to generate the key and send that key simply to the other party – the other party has no influence on the key. Using a key-agreement protocol avoids some key distribution issues related to these systems. If the sender and receiver wish to exchange encrypted messages, each must be equipped for encrypting the messages to be sent and decrypting the messages received. The type of equipment they need depends on the encryption technique they can use. If they use a code, they both need a copy of the same code. If they use code, they need appropriate keys. If it is a symmetric key code, both must have a copy of the same key. If it is an asymmetric key with the public/private key property, both need the public key of the other..