If you're using Netscape Navigator, look for a picture of a key in the lower corner of your screen. With Internet Explorer, a lock pops up when the line is safe. No security expert I consulted would do a credit card transaction over an open line. This involves two questions, not one. Security experts say that, at present, encryption is looking pretty strong.
Some codes seem almost unbreakable.
Even with strong codes, however, a vendor can carelessly violate its own security system. Calif. Fortunately, bank and brokerage accounts offer other layers of protection. If the certifier errs, it may be liable for any money you lose. Netscape users can find a firm's certificate by clicking on the little picture of the key. Even more security is in the works.