    





    The NSA, of course, couldn't be expected to h~ve
    much interest in codes that ~t could not break, and a
    good many critics complained that letting the NSA
    work on the DES was like putting the fox on sentry
    duty around the hen house.
    
    Their uneasiness grew when the NSA persnaded
    IBM, ~hich developed the winning algorithm, to
    withhold the working papers used tO develop it. The
    NSA insisted that this was only a security precau-
    tion in the best interests of all users, but it looked to
    many as if the government was simply trying to lock
    up the algorithm's mathematical roots.
    
    When computer scientists tned to publish papers
    suggesting that the new DES was breakable, the
    NSA tned to classify their work. One of the
    agency~s employees, a man who once proposed to
    keep tabs on the 20 mill~on Americans with crirn~nal
    records by w~nng them with transponders, even at-
    tacked the cntics' patriotism in an engineering jour-
    nal. The NSA finally agreed to meet with dissenters,
    then promptly destroyed all tapes of the confronta-
    tion. Inventors working on cryptographic devices
    found their patent applications class~f~ed and were
    threatened w~th prosecution for even discussing the
    equipment.
    
    The NSA claimed it would take 91 years of com-
    puter work to break the DES key. According to
    Stanford's Hellman, however, "DES could be
    broken by an enemy willing to spend twenty million
    dollars on a computer that could test all the possible
    keys in less than a day. " The DES key is a string of
    O's and l's, known as bits. It is 56 bits long. All
    you'd have to do to make it unbreakable would be
    to switch to a key with 128 or more bits. Since it
    wouldn't make the DES device much more expen-
    sive, why was the government being so stubborn?
    
    "It occurred to us," Hellman says, "that the
    NSA wanted an algorithm that it could crack. That
    would prevent anyone else in the country from
    us~ng a foolproof code."
    
    With that controversy to prepare their way, the
    public-key codes have received a warm welcome
    from just about everyone but the government
    Some New York banks have already decided to re-
    3ect the NSA-backed 56-bit encryption standard.
    An officer at Banker's Trust Company said his
    company refused to go along with the federal plan
    because it "did not meet all the bank's re-
    quirements." Bell Telephone has also rejected DES
    on security grounds.
    
    These corporations may be better served by
    Drivate comPanies now hoping to market coding
    devices based on the systerns MIT and Stanford in-
    ventors are try~ng to patent. "Since we would share
    some of the royalties," Hellmann says, "some
    government people suggest our opposition to DES
    is motivated by self-~nterest. Sure' we would benefit
    if public-key systems go into widespread use. But
    
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    the facts are that our method provides real protec-
    tion and DES can be broken."
    
    ~vest is already consulting for companies that
    hope to market foolproof systems. "What we
    want," he says, "is to develop an add-on encoding
    de~ce for computer terrrunals that any user could
    afford. We're building a prototype now and work-
    ing to see that it ends up in the marketplace. " Bell
    Northern Labs, a subsidiary of the Canadian phone
    company, has hired Diffie to help make electronic
    eavesdropping more difficult. At the company's
    Palo Alto research facility, he is leading a crypto-
    graphic research group that wants to show callers
    how they can mask their identity.
    
    Some computer experts, such as George Feeney,
    who invented the concept of EDP time sharing and
    who heads Dun and Bradstreet's advanced-technol-
    ogy group, volce concern about the practicality of
    these promised systems. "The unbreakable code is a
    brilliant piece of conceptual work," Feeney says.
    "These inventors have done an incredib]e 30b. But
    some of us wonder whether the process may turn
    out to be beyond the current state of the computer
    art. We still don't know how long it's going to take
    to get this dream going and whether the cost wiI1 be
    realistic. "
    
    The NSA, though' has already begun to whine
    about the prospects of companies and private in-
    dividuals communicating over foolproof lines. The
    agency's director, Vice Admiral Bobbie Ray Inman,

    





    is so anxiaus that he recently broke official policy to
    
    C - 7
    
    