This study developed a mail server program using Socket API and Python.The program uses the Hypertext Transfer Protocol(HTTP)to receive emails from browser clients and forward them to actual email service providers vi...This study developed a mail server program using Socket API and Python.The program uses the Hypertext Transfer Protocol(HTTP)to receive emails from browser clients and forward them to actual email service providers via the Simple Mail Transfer Protocol(SMTP).As a web server,it handles Transmission Control Protocol(TCP)connection requests from browsers,receives HTTP commands and email data,and temporarily stores the emails in a file.Simultaneously,as an SMTP client,the program establishes a TCP connection with the actual mail server,sends SMTP commands,and transmits the previously saved emails.In addition,we also analyzed security issues and the efficiency and availability of this server,providing insights into the design of SMTP mail servers.展开更多
Forward secure signature can protect the security of signatures previous to the key exposure. Server-assisted signature is a special digital signature in which the signer allies one server to produce the signatures. I...Forward secure signature can protect the security of signatures previous to the key exposure. Server-assisted signature is a special digital signature in which the signer allies one server to produce the signatures. In this paper, server-assisted for-ward-secure threshold signature is proposed. The system is composed of n1 servers and n2 users. Each user and each server holds a partial secret, respectively. To produce a valid signature, users and servers need to cooperate to complete the work. The partial secrets of the users and servers are updated by a one-way function at regular intervals, while the public key is always fixed. Even if all the current partial secrets are exposed, the signatures pertaining to previous periods are still valid.展开更多
文摘This study developed a mail server program using Socket API and Python.The program uses the Hypertext Transfer Protocol(HTTP)to receive emails from browser clients and forward them to actual email service providers via the Simple Mail Transfer Protocol(SMTP).As a web server,it handles Transmission Control Protocol(TCP)connection requests from browsers,receives HTTP commands and email data,and temporarily stores the emails in a file.Simultaneously,as an SMTP client,the program establishes a TCP connection with the actual mail server,sends SMTP commands,and transmits the previously saved emails.In addition,we also analyzed security issues and the efficiency and availability of this server,providing insights into the design of SMTP mail servers.
基金the National Natural Science Foundation of China (60703089)the National High-Technology Research and Development Program of China (863 Program) (2006AA012110)
文摘Forward secure signature can protect the security of signatures previous to the key exposure. Server-assisted signature is a special digital signature in which the signer allies one server to produce the signatures. In this paper, server-assisted for-ward-secure threshold signature is proposed. The system is composed of n1 servers and n2 users. Each user and each server holds a partial secret, respectively. To produce a valid signature, users and servers need to cooperate to complete the work. The partial secrets of the users and servers are updated by a one-way function at regular intervals, while the public key is always fixed. Even if all the current partial secrets are exposed, the signatures pertaining to previous periods are still valid.
