Asymmetric encryption method, advantages and disadvantages


The asymmetric encryption is a concept of cryptography that uses key pairs. The one key is the public one (Public Key) and the other is the private key (Private Key). Data that are encrypted with the public key can only be decrypted again with the private key [1]. In order for the sender to send an encrypted message to the recipient, the sender needs the recipient’s public key (see picture).


method asymmetric encryption

Bob and Alice want to exchange messages through an insecure channel (e.g. Internet). In order to ensure that the information that will be sent will not be read by a third party (Eve), Bob and Alice decided to encrypt the messages with the asymmetric encryption. For this purpose Bob needs Alice’s public key. The public key is visible to everyone (even to Eve). The publication of the key may happen, for example, trough an emal or a public server. With Alice’s public key, can now anyone send encrypted messages to Alice. However, only Alice can, with her private key to decrypt again the message.


  • The private key does not need to be transmitted via a secure channel (as opposed to the symmetric encryption) in order for the encryption to be successful
  • There is the possibility of an electronic signature (digital signature)


  • The high cost to encrypt and decrypt messages (much slower compared to symmetric encryption)[2]


[1] A. Menezes, “Handbook of Applied Cryptography “, CRC Press, 1996, ISBN 978-0849385230.
[2] Asymmetrische Verschlüsselung. – Stand 29.11.2016

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