Abstract: Information such as message identifier, sender, recipient, timestamp, etc., are recorded in a record in a local database as an e-mail message is sent out. A DSN counter is set equal to the total number of recipients, thus allowing returned messages to be compared against this counter to thwart a capture/replay attack. When a DSN message is received at the computer system it includes the originally sent e-mail message. The DSN message may be legitimate or it may be a faked DSN message. The system searches the local database for a record having information that matches with the returned e-mail message. If a match exists, the DSN message is legitimate and it is delivered to the original sender. If no match exists, then the DSN message has been faked and appropriate action is taken. When a match occurs, a match count value is incremented for that record and compared against the originally stored DSN count value.

Abstract: The invention relates to a method and a system for producing synthetic gas from biomass by high temperature gasification, including: feeding raw material, carbonizing, pulverizing the charcoal, and transporting charcoal powder to the gasification furnace for gasification. Prior to pulverizing, the charcoal is reduced to a normal pressure by a decompression feeding system of charcoal, pulverized into powders, and transported to a supercharging feeding system of charcoal powder by normal pressure transport gas. The pressurized charcoal powder is transported to gasifier. The high-temperature charcoal at an outlet of carbonization furnace is cooled to 60-200° C. by a cooler, and transported into the decompression feeding system to be depressurized. The charcoal powder with pressurized is ejected to gasifier by an ejector, pyrolysis gas produced from carbonization furnace is used as carrier gas, and the ratio of solid to gas in the transportation pipe for charcoal powder is controlled at between 0.03 and 0.