On September 15th the Israeli Defense Minister was ordered to charge the 43 members of intelligence Unit 8200 with a criminal offense for disclosing details of intelligence operations. Actually, most of the 43 who signed an open letter enouncing tactics (eavesdropping, blackmail) used to recruit Palestinian informants had either never worked on those operations or were not currently doing so. Those techniques were no secret, but the open letter brought forth an overwhelming reaction, mostly negative, against the 43 reservists. Hundreds of other Unit 8200 members issued an open letter denouncing the 43 for being attention seeking political opportunists who did not know what they were talking about, or didn’t care.
In was only in 2011 that Israel revealed many details of Unit 8200, which has long handled cryptography, computer hacking and electronic warfare in general. It's long been known that a “Unit 8200” of the Israeli army specialized in cracking codes for the government. This was known because so many men who had served in Unit 8200 went on to start companies specializing in cryptography (coding information so that no unauthorized personnel can know what the data is.)
Unit 8200 is crucial for supplying information about planned attacks on Israel, especially terror attacks on Israeli territory or Israelis in other countries. These counter-terror efforts rely on fresh intelligence and lots of speed in carrying out raids and attacks against terrorists. The objective is simple; catch the terrorists before they can attack Israelis. A key source of intelligence is an extensive informant network in Gaza, the West Bank and many Arab countries. Israel was able to build and maintain such a network in Arab areas because they have so many police and military intelligence personnel who speak Arabic and often work for Unit 8200. A large segment of the Israeli population even looks like Arabs, because they are descendants of the half a million Jews expelled from Arab countries in the late 1940s. These Israelis can easily pass as Palestinians and often do when collecting intelligence.
Few Palestinians willingly provide information to the Israelis, so the Israelis developed the BBE (Bribes, Blackmail, Extortion) System. Actually, BBE uses ancient techniques, but with tweaks to meet Israeli needs. Thus Israeli agents seek out Palestinians who could be bribed, blackmailed or extorted to provide information. This often provides enough information to identify the key people in a Palestinian terrorist organizations. The Israelis then stage raids or attacks to arrest or kill these key people. It wasn't just the organizers and leaders they were after, but the "technicians" who could build bombs. The Palestinians called these guys "engineers," and they were a talented bunch. You can note their absence by the increasing number of accidental explosions in Gaza, as less expert bomb builders made fatal mistakes. The lack of leadership meant that more and more suicide (and other type) attacks failed. It's not easy staging a suicide attack. The actual suicide bomber is only one person in a team of up to a dozen people who make the bomb, scout the target area and figure out how to get the bomber past Israeli security.
Israel also has a world class electronic monitoring system, which Unit 8200 is a heavy user of. This system makes it difficult for the Palestinians to communicate. If they use any kind of telephone or radio, they risk being overheard. If they speak in code, the Israelis have databases of information on codes used before, and codebreaking software, and analysts, to quickly break new codes. All information is stored in databases and can be quickly retrieved. The planning process for new raids has been automated, and the troops, police or commandoes can be briefed and on their way in hours. This means that if a terrorist operation is detected at any point, the Israelis can usually disrupt it.
In short, Unit 8200 will continue operating because for most Israelis it’s a matter of life or death.