Applications of e-sign

This thesis is based on explanation of technical and law concept of e-sign application which is needed for data transmission between transmitter and receiver in an internet/intranet network. E-sign is a base structure to revaluate the Ecommercial and E-government purposes. E-sign algorithms are created by asymmetric encryption algorithms. `PKI? system has been created firstly by Diffie- Hallmann in 1976. To e-sign a message, it has to be hashed by a hash function and then e-signed by an asymmetric encryption algorithm. If it is needed to encrypt the contents of the message also then one of symmetric or asymmetric algorithm must be used. Both RSA and El-Gamal asymmetric encryption algorithms have abilities to encryption and e-signing together. Elliptic curve algorithms obtain more security even it uses lower bit levels. E-sign applications have to be created by `PKI? standards. These applications obtain security and law validity of a message and it puts away restriction of time and space. Key words: E-sign, asymmetric encryption, RSA, Hash functions, SHA series, PKI.