Last Thursday (12th) French computer scientist Antoine Joux announced that in a commonly used algorithm, find a weak point; this algorithm is called "MD5" (message summary 5), often match digital signatures (Digital Signature " )use. Then, the four Chinese researchers issued a report that there is a way to solve another algorithm called "SHA-0" (Safety Phase Rate Algorithm 0).
Although these are just a preliminary study, the new discovery may make the adults easier to implant in the computer program, or forgee electronic signatures - unless different, safer algorithms.
The third may be more explosive announcement, which is scheduled to be published at the Crypto 2004 meeting held in Santa Barbara, California on Tuesday (17th).
Elibiham and Rafi Chen originally planned to release reports in the meeting, pointed out several methods of cracking the "SHA-0" algorithm security function. Now, they intend to further discuss the "explosive message" of the "SHA-1" algorithm in the meeting. This meeting is scheduled to start at 7 o'clock in the evening of the Pacific Day.
"SHA-0" is not perfect, it is the fact; but if "SHA-1" founds a major weakness, depending on the details, it may shock the computer security community.
Currently, the "SHA-1" embedded in the same level of algorithm, "SHA-1" embedded in a wide program such as encryption software (PGP) and Secure Skay Agreement (SSL). "SHA-1" has been certified by the American Standards and Technology Research Institute (NIST), and is the only signature algorithm for the US government's "digital signature standard". "SHA-1" generates 160-bit numbers and strings, the length is longer than the 128-bit generated by the MD5, so it is considered to be safer.
Crypto 2004 General Chairman Storage Tek Senior Researcher Jim Hughes said on the morning of Jim Hughes, this message is too important, so he has prepared the first online broadcast (Webcast) in the 24 years. In the submission of the code to the encryption, hughes revealed that three research reports of the Hash Collisions were proposed. "One of the Joux's research found.
When receiving the phone access, HUGHES said: "If you find that there are two contracts that have the same number of contracts, you can use the contract to replace the two contracts. When you have a court, which one is a valid contract, at least Gray zone. That possibility is extremely high. "
Whether it is "MD5", "SHA-0" or "SHA-1" algorithm, computer scientists use a so-called Hashfunctions. With these ranking algorithms, you can mix all kinds of information content such as email messages and operation system cores, theoretically, theoretical, unique, Fingerprint. The original information content is slightly changed, even if only one letter is only more than one letter, the fingerprint generated after the algorithm is used is still different.
The protective mechanism for safe applications is the uniqueness of architecture in the fingerprint. In case, a unpleasant hacker has the same fingerprint file with different information content, then the copy fingerprint - "Hash Collision" - will confirm the software that is implanted back door For security, it is available for users to download and execute. In this way, the heart can take the opportunity to fake email signatures, indicating that the bank account of someone is moved.
Researchers have long known that there is no actual encryption algorithm that can actually use is absolutely safe; what they can do is to design a rigid algorithm for copying fingerprints that need to be copied when they need to be released. "SHA-1" is considered safe and reliable, and it is impossible to use the skills that are currently known. It is impossible to create a lot of collision.
However, if "SHA-0" potential weaknesses also appear in "SHA-1", that means copying the speed of the fingerprints can speed up approximately 500 million - If a bunch of high-speed personal computers are connected to the net, capable Dacted this goal.
The weakness of the "MD5" algorithm is a more urgent threat. Open source Apache network server products use "MD5" to make sure that the source code on dozens of image websites is not tampered, safe execution. Sun Solaris FingerPrint Database also uses the same whispering algorithm technology. The "MD5" weakness that has been taken out in recent days, means that hackers may have mixed collision with standard personal computers within hours. However, to write a specific rear door program, then over the same mixture, it may be more time.
That is, HUGHES suggests that programming staff is best to start discarding "MD5". He said: "Since the weakness of this algorithm is now exposed, it is now the time to evacuate before the effective attack is launched."
From:
ZDNET
