Tag Info

New answers tagged

0

No. $\:$ The adversary lets the public key and the private key and the ciphertext all equal the empty string. $\:$ By doing so, the adversary either created a valid key pair on its own or produced a ciphertext under its public key without the protocol having been followed.


1

This question both describes the SRP-Z variant and mentions that the patent should expire in three years. I think the patent in question is this one, but I'm not sure: US 6539479.


0

What you are looking for is so called white-box cryptography. That said, you should definitely check if you can't get away with digital signatures. The reason is that white box cryptography is a special case of program obfuscation that is quite hard to achieve. Existing, practical schemes do not rely on hard problems but rather on not being broken so far. So ...


1

According to Handbook of Applied Cryptography (15.3.2, ii), ANSI X9.9 (which SEJPM mentioned in the comments but I have no access to) defined CFB-MAC only as a compatible alternative to CBC-MAC: The X9.9 MAC algorithm may be implemented using either the cipher-block chaining (CBC) or 64-bit cipher feedback (CFB-64) mode, initialized to produce the same ...


2

I've been looking for the test vectors also. https://github.com/NTRUOpenSourceProject/ntru-crypto/blob/master/reference-code/Java/Encrypt/build.xml refers to ""com.securityinnovation.testvectors.NtruEncryptTestVectorGenerator" " I haven't looked any deeper than this, but it looks like they don't publish test vectors, but give you a means of generating them ...


-1

Yes absolutely. I believe that web cams make excellent true random number generators, but. The camera has to be operated within a visually managed environment. This is necessary to determine and control entropy of the resultant images for quality control purposes. The trick is not to rely on the scene the camera sees, but the image noise. Only God ...


0

A simple way to think of the S-boxes of DES when it comes to a hardware implementation is: 8 independent ROM ICs, each with 6 address input lines and 4 data out lines. In an educational physical implementation with retro standard ICs, two such ROMs fit a 4 kiB EPROM (a 2732). Some actual software implementations of DES do group S-boxes two by two in order to ...


9

What choice did they have? F1 is a bitwise function with three inputs and one output. There are $2^8 = 256$ such functions. Only 70 of them are "unbiased" (i.e. have as many 0 and 1 outputs in their image). If you further require that each input, as well as the order of inputs, matters for the output, you are left with only 36. However, those 36 are all ...


0

What you are describing sounds something like a Merkle Tree: https://en.m.wikipedia.org/wiki/Merkle_tree Note that the organization of a Merkle tree is fairly arbitrary; the graph can look like just about anything so long as it is acyclic. The interesting aspect of a Merkle tree is that any change anywhere in the data "bubbles up" the tree to the root, ...


1

As for "how to build the substitution as hardware", it should be easy if you know any of the hardware description language (eg. VHDL or Verilog). Simply write the Sboxes of DES, then the synthesis software will handle the rest. You can also "synthesis" by hand, although that may take a lot of effect. Still, I'm not sure if this is what you are looking for. ...


0

I managed to find it out by reproducing the test vectors. TL;DR: The standard assumes that you use the low 4 bits of the last byte of the hash, regardless of its length. So replace 19 in the original DT definition with 31 for SHA-256 or 63 for SHA-512 and you are good to go. Finding this out wasn't completely straightforward, as the standard only has a ...


0

Here's a good amount of hard data on a variety of curves, well-analysed and the findings summarised in a readable way: http://safecurves.cr.yp.to/ The chosen answer is not nearly up to the same standard of analysis and, I would argue, deceptive, whether maliciously (v. unlikely) or just due to lack of understanding of basic research methodology.


2

Edwards curves can be implemented using a unified formula for addition and doubling; i.e., one can implement addition such that $$\mathrm{dbl}(P)=\mathrm{add}(P,P).$$ Performance wise it is however more efficient to consider both functions separately, since the doubling can be implemented more efficiently than the addition. Depending on the representation ...


0

Many ABE schemes support Threshold Cryptography in the sense that the policy that is used to share a random secret supports threshold gates. This is also not limited to Ciphertext-Policy ABE. Key-Policy ABE schemes also support threshold policies. The threshold policy is usually written with the of operator such as 2 of (attribute1, attribute2, ...



Top 50 recent answers are included