Asymmetric cryptography, first proposed by Diffie and Hellman in the 1970s, is used to guarantee confidential and secure communication online. It uses two different cryptographic keys, one for encryption and another for decryption. Each party has a pair of keys (a private key and a public key); the public key can be shared with anyone, while the private key is kept secret. If a sender sends a message encrypted with the recipient’s public key the recipient can then decrypt it with their corresponding private key. On the other hand, if a sender encrypts a message with their own private key, it can be decrypted using the sender’s public key. This later use case increases verifiability and therefore the trustworthiness of the sender’s communications.
This differs from symmetric key encryption, which uses the same key for both purposes. Asymmetric cryptography does not require the exchange p. 25of secret keys in advance, which considerably reduces interception risks. However, to achieve the same level of security an asymmetric key needs to be an order of magnitude larger (in terms of bit sizes) and is considerably slower to process.
Asymmetric cryptography is commonly used in secure Internet protocols, such as Transport Layer Security (TLS), digital signatures and encrypted email.
Further reading:
See also: CRYPTOGRAPHY, ENCRYPTION KEY
Diffie, W. and Hellman, M., 1976. New directions in cryptography. IEEE Transactions on information theory, 22(6), 644-654, https://doi.org/10.1145/3549993.3550007.
Kessler, G.C., 2003. An overview of cryptography. www.garykessler.net/library/crypto.html.
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Diffie, W. and Hellman, M., 1976. New directions in cryptography. IEEE Transactions on information theory, 22(6), 644-654, https://doi.org/10.1145/3549993.3550007.
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Kessler, G.C., 2003. An overview of cryptography. www.garykessler.net/library/crypto.html.
