Implementation of Secure Message Transfer System Using Controlled Trusted Center Based on RSA

This paper presents data transfer systembetween two users using the asymmetric-keycryptography. Asymmetric-key cryptography orpublic-key cryptography is cryptography in whicha pair of keys is used to encrypt and decrypt amessage so that it arrives securely. A message canbe encrypted with the receiver’s public key anddecrypted with the receiver’s private key toprovide security. A higher level of security can beachieved by placing controlled trusted center as adirectory of public keys. Controlled TrustedCenter keeps the public key of the registered usersin its directoryand responsible to respond to anyinquiry about the public key. The public-keyannouncements can include a timestamp and besigned by an authority to prevent interception andmodification of the response. A signature is atechnique for non-repudiation based on the publickey cryptography. RSA digital signature and SHA-1 hash function are applied to provide integrityand authentication during the public keydistribution. RSA encryption algorithm is alsoused for encryption in this secure messagetransfer system. RSA is two algorithms: one forasymmetric encryption and one for signatures