TECHNICAL APPROACH

The proliferation of unsolicited commercial e-mail messages has caused a reaction from technical and legal Points of view. Some technical solutions have been proposed [DN93, GJMM98, H97], but at this moment, not All of them have been implemented. The most extended technical solution is the use of a single e-mail address and a filter. The messages received are filtered, and all suspicious messages are deleted or stored in a different folder. Filters and Blockers may help to reduce the spam volume but cannot eliminate it entirely. If the filtering is realized by The receiver, then he must pay for the reception of the messages, before the filtering is done. Filtering in the Internet Service Provider (ISP) reduces the volume of messages received by the user, and the cost of Downloading. Filtering can be done in function of the sender address (if the sender address is identified as a Spammer’s address). However, spammers can use multiple addresses and discard the addresses already used. Filtering based on keywords (in the subject or in the body of the message) can also be used. However, this approach is not cent percent accurate and can produce the removal of desired or solicited messages. Another easy solution is the use of different addresses for different purposes. An address that has been collected by a spammer must be discarded. But the change of address is not suitable for the users, because They have to notify the change of address to all his correspondents. The channelization of a single address [H97] can be used to solve this problem. If a user defines a few Channels over his address, then can adjust the addresses from where the channel can receive messages, Creating public and private channels. A channel can be closed without any repercussions on other channels. Micropayments can also be used. If a coin of a fixed value is required for the reception of the message, The cost assumed by spammers can be discouraging. If a message is received from a not commercial source, The receiver can return the coin. This approach can be used in conjunction with channelization. The user Can open a public payment channel allowing the reception of messages from all sources. Spam on mobile devices can be considered an even worse intrusion, because the message is delivered directly to a person’s handset, and for this reason, the message will find the person immediately. Due to the Price of an SMS, spam makes money for wireless operators and makes fighting spam a complex dilemma For carriers. Carriers can deploy a network solution for protection against specific service attacks and allow Subscribers to improve the solution by setting up filters. In the mobile environment, the exploration of potential receivers’ addresses is different. Brute force Attack to every possible mobile address (phone number) is commonly used.