You're right; it's called the hidden subgroup problem. Antony
http://stackoverflow.com/users/257111/ninefingers On 03/03/11 16:49, Billy O'Neal wrote: > If I'm reading this right, it's nothing new. > > The basic idea is that the RSA function is periodic (it does involve a > modulus after all), so applying it to the same message over and over > again should result in a cycle back to the cleartext (if the author of > the presentation indicated is correct). While this is true, there's no > way for the attacker to know when they've cycled back around to the > message text, unless (s)he can control what the plaintext message is. > And if the attacker already knows part of the plaintext, RSA is > already broken -> > http://en.wikipedia.org/wiki/RSA#Attacks_against_plain_RSA . > > This is why RSA messages are padded with pseudorandomized data, to > prevent attackers from determining these kinds of things. > > Please correct me if I am wrong. > > Billy3 > ------------------------------------------------------------- > Computer Science Student - Case Western Reserve University > http://stackoverflow.com/users/82320/billy-oneal > > On Thu, Mar 3, 2011 at 11:01 AM, rachid baih <[email protected]> wrote: >> A worked example >> The public key is (n = 5183, e = 8609). >> The private key is (n = 5183, d = 209). >> >> m= 127 to encrypt >> c = >> 127^8609 mod 5183 >> c = >> 2324 >> >> to decrypt c = 2324 >> >> 2324 ^8609 mod 5183 = 3748 >> >> >> 3748 ^8609 mod 5183 = 123 >> >> >> 123 ^8609 mod 5183 = 2257 >> >> >> 2257^8609 mod 5183 = 3247 >> >> >> 3247^8609 mod 5183 = 127 >> >> >> 127 ^8609 mod 5183 = 2324 >> >> >> Now we have successfully decrypted c with m = 127 >> >> Take any number c ( rsa encrypted message) You can continue encrypting >> process (with rsa function ) >> no matter what number c you start with, you will always eventually >> reach >> m the decrypted message. >> plez visit >> https://docs.google.com/document/d/1sTHB52526LQW3YnU39HdZ49pXIlQKOXGAsm3oIdUELM/edit?hl=en# >> >> -- >> You received this message because you are subscribed to the "Crypto++ Users" >> Google Group. >> To unsubscribe, send an email to [email protected]. >> More information about Crypto++ and this group is available at >> http://www.cryptopp.com. > -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [email protected]. More information about Crypto++ and this group is available at http://www.cryptopp.com.
