JIT_V5_N2_RP3 Jitendra Singh Laser Vinaykumar Jain Journal on Information Technology 2277-5250 5 2 19 26 Biometric Sender Authentication, Speech Recognition, Diffie Hellman (DH) Public Key Cryptosystem, Man-In- The-Middle Attack, Speech and Message Encryption and Decryption The objective of this work is to develop Biometric based sender authentication in public key cryptosystems to overcome the man-in-the-middle attack or hacking issues and provide a high level of security. Biometric Technologies are automated methods for verifying or recognizing the identity of a person based on physiological or behavioural characteristics. In public key cryptosystems, authentication is provided either by HASH function, MAC (Message Authentication Code) function or Digital Signature. In this work, the authors have used a Biometric based sender Authentication using Speech Feature in public key Cryptosystem. Here the public key cryptosystem uses Diffie Hellman (DH) algorithm. DH generates a shared secret key between two parties over an insured communication, but DH does not provide Encryption/Decryption and authentication. The man-in-the-middle attack or Hacking is possible in DH, because it does not authenticate the participants. In this work, the authors overcome the authentication and the man-in-middle attack problem by using Biometric based sender authentication. Also the speech encryption and decryption are performed with the message for high security. March - May 2016 Copyright © 2016 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=6000