Non-Repudiation is a characteristic where both party, usually a sender and a receiver from #networking perspective, can’t deny the validity of a message. This will prove that the message is sent by that particular sender, and is received by that particular receiver. It utilises Digital Signature#, Data Integrity#, and Notarisation#.
Non-Repudiation
- TNS3131 Chapter 1: Overview of Network Security
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Symmetric Cryptography
Since both parties are equal, that is both could do encryption and encryption, the receiver could forge# a message and claim it to be sent by the sender.
- Security Service
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Digital Signature
Digital Signature is a #Security Mechanism where hashed# data is appended to (sometimes encrypted# using Rivest-Shamir-Adleman (RSA)#) a data unit, allowing a recipient of the data unit to prove the source and Integrity# of the data unit. It could protect against forgery# due to its Non-Repudiation# nature. At the receiver side, it will either reject (return value 0) or accept (return value 1) the signature.
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Asymmetric Cryptography
As the name suggests, private key can only be hold by the local host whereas public key can be shared among the hosts, or recipients, in the network. Both the public key and private key are encrypted by a cryptographic algorithm.
The public key can only be decrypted by the matching private key, which identify the intended receiver.Public key is used to encrypt messages and verify signatures. Private key is used to decrypt messages and sign (create) signatures. Once the message get signed, it is non-repudiation# as there is only one owner for the private key and they can’t deny to the ownership of the key.