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The triple DES (3DES) block cipher works by essentially running the block through DES three times. Triple DES is also known as "DES EDE" (encrypt-decrypt-encrypt) and under the name given by the standard document: "TDEA". The TDEA algorithm is described in FIPS NIST Special Publication 800-67 Revision 1 where paragraph 3.2 describes the TDEA Keying Options. ...


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Q: How long shall the RSA key be in order to be secure against practical attacks? A: Impractically large. This does not imply that RSA is unsafe against practical attacks; only that some of these attacks must be prevented by ways other than increasing the key size. That's because key size is not a parameter with a major impact on the efficiency of many ...


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It is just customary, and enforced by products like GPG and OpenSSL which include code to block you choosing your own exact bitlength (they enforce padding or rounding, for no particular reason). Here is the GPG code that enforces this, for example: if( nbits < 768) { nbits = 2048; log_info(_("Keysize invalid; using %u bits\n"), nbits ); ...


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There is no cryptographic advantage in picking any particular alignment for RSA key sizes, whether it's powers of 2, multiples of 64, multiples of 2, ... The difficulty of cryptographic attacks pretty much grows with the number of bits. As already noted by fgrieu, there is a slight advantage to the defender in working with sizes that are a multiple of 32 or ...


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Assuming the Alphabet is only 26 values, you have: 26! or 403,291,461,126,606,000,000,000,000 ways of rearranging it. This is not key space for a single substitution alpha. You would need to be able to create, or at least have the means of creating, n random Alphas for the number to be relevant. An encryption of 3 characters (say abc) over a random 26 ...



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