Factoring RSA 512-bit keys is now squarely within the reach of anyone who is determined enough.
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The timings were made on a 2GHz Pentium.If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.Opaque formats include PostScript, PDF, proprietary formats that can be read and edited only by proprietary word processors, sgml or XML for which the DTD and/or processing tools are not generally available, and the machine-generated html produced by some word processors for output purposes only.But it's not sufficient for keeping data confidential much into the future, or for keeping it secret from an adversary prepared to devote a few million dollars to the problem.It complements the GNU General Public License, which is a copyleft license designed for free software.Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based.Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book.A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.Even if you were able games car need for speed underground 2 to sacrifice this amount of CPU to every log on, it leaves us with the problem that an attacker can effectively burn a second of CPU time on our server by firing some random data.
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You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else.Any member of the public is a licensee, and is addressed as "you".Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles.A larger key increases the maximum number of bytes that we can encrypt at once, and also the security of the encryption.We recommend this License principally for works whose purpose is instruction or reference.Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections.If we use a 4096-bit modulus, it takes around a second of CPU time to decrypt a block of data.But it has a serious problem in practice: With every doubling of the RSA key length, decryption is 6-7 times times slower.