Implements contributory Diffie-Hellman Group Key Agreement examples
[1] Burmester, M., Desmedt, Y. (1995). A secure and efficient conference key distribution system. In: De Santis, A. (eds) Advances in Cryptology — EUROCRYPT'94
[2] Y. Kim et al., “Group Key Agreement Efficient in Communication,” IEEE Transactions on Computers, vol. 53, pp. 905–921, Jul. 2004.
[3] Y. Amir et al., “On the Performance of Group Key Agreement Protocols,” ACM Transactions on Information and System Security, vol. 7, pp. 457–488, Aug. 2004.