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4 votes
Accepted

In what cases might PRESENT be implemented as encryption-only?

So in what cases might we need only encryption but not decryption? It seems strange we would encrypt something that does not need decrypting at some point. For example, the CTR mode uses only ...
kelalaka's user avatar
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4 votes
Accepted

Are there recommended modes of operation for lightweight ciphers?

When using lightweight ciphers, the block size can make a huge difference to security. Fortunately, there has been a lot of work in recent years on tight bounds for modes of operations, and methods ...
Yehuda Lindell's user avatar
4 votes

What is the time complexity of the basic components of a symmetric cipher?

I cannot find anything simple on time complexity for cryptographic components (functions?) as describable above You wont really find anything because those components are generally not described that ...
Richie Frame's user avatar
  • 13.1k
3 votes

What is the time complexity of the basic components of a symmetric cipher?

You may need to specify your model of computation to make your question answerable. In some models bitwise XOR is ${\rm O}(n)$ in the number of bits being XORed; it others it can be ${\rm O}(1)$, ...
Ilmari Karonen's user avatar
3 votes

What affect does the permutation layer have on the avalanche effect?

Permutation layer diffuses the small changes globally(tries to spread over the complete block). If permutation is not well thought out, then diffusion may be weak and changes may not spread ...
crypt's user avatar
  • 2,449
2 votes

Why is PRESENT 31 rounds?

I think that the reason for 31 rounds is in their paper, Section 5.1. Bogdanov et al. have approximated a small $2^{−43}$ bias that occurs after 28 rounds of linear analysis. Therefore they added ...
Paul Uszak's user avatar
  • 15.5k
2 votes

What is the role of the round counter in the key schedule of PRESENT?

to prevent self-similarity of key scheduling The importance of constant addition (not only present cipher) appears in preventing key schedule-based attacks such as slide attack ,related key attacks ...
hardyrama's user avatar
  • 2,126
2 votes

In what cases might PRESENT be implemented as encryption-only?

A bona fide use case for encryption only is inside a true random number generator (TRNG). If you have something small like:- it's common to whiten the raw entropy signal using a cryptographic ...
Paul Uszak's user avatar
  • 15.5k
2 votes

In what cases might PRESENT be implemented as encryption-only?

Ciphers that are targeted for light-weight applications often have some common, but one-off, use cases. I have an IC with and ADC that is passively powered via RFID, and then sends encrypted data via ...
b degnan's user avatar
  • 4,830
2 votes
Accepted

What affect does the permutation layer have on the avalanche effect?

The avalanche effect is the property of a cryptographic primitive, whereby flipping a single input bit causes (on average) 50% of all of the output bits to flip. This can be simply accomplished by an ...
Paul Uszak's user avatar
  • 15.5k
2 votes
Accepted

What is the time complexity of the basic components of a symmetric cipher?

I assume a cipher has a total time complexity. Where can I find the time complexities of a given cipher, especially DES, PRESENT and AES? And is there available time complexities per round of these ...
kelalaka's user avatar
  • 48.8k
2 votes
Accepted

How are the four 8-bit permutation tables of Present cipher calculated?

In short: Trace back where bits come from in every byte in the output state (8 bytes) of the SP_network. In one round, after we have xored the round key bits, we have 8 bytes (a 64 bit word, with ...
Henno Brandsma's user avatar
2 votes
Accepted

How to obtain inverse key stream efficiently on Present cipher?

The PRESENT key schedule operates on a register the same length as the key size. The left most 64-bits are extracted as round keys and then the register updated by performing a 61-bit left rotation on ...
Daniel S's user avatar
  • 23.9k
1 vote

Construction of S-Box in PRESENT

The design rationale for the S-box is given in section 4.3 of the paper. I'll try and expand on the reasoning. The worst sort of S-box would be a linear function i.e. one where every bit of output is ...
Daniel S's user avatar
  • 23.9k
1 vote

Where can I find test vectors for the PRESENT cipher with a 128-bit key?

The test vectors for PRESENT cipher 128 bit key size are: $$ \begin{array}{c|c} \def\tabentry#1 {{\scriptstyle\mathtt{#1 }}} K & P & C \\ \hline \tabentry 0x00000000000000000000000000000000 &...
hardyrama's user avatar
  • 2,126
1 vote
Accepted

What is the reasoning behind the PRESENT key schedule?

Question 1 In simple terms, how does the key schedule protect it from key related attacks? According to the paper "Lightweight Block Ciphers Revisited: Cryptanalysis of Reduced Round PRESENT and ...
Ella Rose's user avatar
  • 19.6k
1 vote
Accepted

If PRESENT had different permutations, would that protect it against Statistical Saturation Attack?

For your first question, there are two permutations in PRESENT that we could consider changing: The nonlinear layer, i.e. a parallel application of an S-box. The linear layer, which is a bitwise ...
Aleph's user avatar
  • 1,876
1 vote
Accepted

How does the PRESENT cipher's permutation affect all rounds when it repeats after every three rounds?

Yes, you might think that the bits return to their original positions. But they don't because those aren't the bits you're looking for. They've changed. Specifically, you need to consider the ...
Paul Uszak's user avatar
  • 15.5k
1 vote

Test vectors for PRESENT algorithm?

Plaintext Key Ciphertext 00000000 00000000 00000000 00000000 0000 5579C138 7B228445 00000000 00000000 FFFFFFFF FFFFFFFF FFFF E72C46C0 F5945049 FFFFFFFF FFFFFFFF 00000000 00000000 0000 A112FFC7 ...
RandyJ149's user avatar

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