| 摘要 |
An electronic mail transmission/reception system is provided, capable of maintaining the confidentiality of restricted attachments desired to be limited in destination, thereby ensuring the security of the restricted attachments. A system management server 11 of an electronic mail transmission/reception system 10 includes: first conversion means for hashing a restricted attachment intended for a predetermined destination by a one-way hash function, and converting the restricted attachment into a first hash output value; first storage means for storing the first hash output value for the restricted attachment converted via the first conversion means; second conversion means for hashing a received attachment by the one-way hash function, and converting the attachment into a second hash output value; and destination restriction means for comparing the first hash output value with the second hash output value, and when these hash output values are equal, transmitting the attachment corresponding to the second hash output value only to the predetermined destination. |
