28 votes
Accepted

What is the progress on the MIT LCS35 Time Capsule Crypto-Puzzle?

2) Has anyone claimed to make any progress with this challenge? Ah that question I can answer now... I found the solution on the 15th of April 2019 and sent it to the MIT's CSAIL on the 16th of ...
TacticalCoder's user avatar
7 votes
Accepted

Has Burdges and De Feo's concept of Delayed Encryption ever been implemented?

There is PoC code for the De Feo-Masson-Petit-Sanso VDF here: https://github.com/isogenies-vdf/isogenies-vdf-sage. It's easily adapted to Delay Encryption.
Luca De Feo's user avatar
6 votes

Time Based encryption

"Impossible" might be appropriate. And "Not really a cryptography issue." Summing up Artjom's and Geoffroy's comments, nothing can stop you pointing a camera at the screen. Or perhaps taking a screen ...
Paul Uszak's user avatar
  • 15.4k
5 votes
Accepted

Dead-Man's Switch Cryptography?

The scheme you propose is not possible as far as I know. This is because $enc(M)$ has to be known for the dead-man's switch to operate (in a time capsule like way, as you described), but there is no ...
Ruben De Smet's user avatar
5 votes

How would we design a fast circuit to solve LCS35?

Turns out the LCS35 problem was first solved on April 15, 2019 by Bernard Fabrot. It took 3.5 years of runtime on a single core of a standard modern CPU, using GMP. Independently, the Cryptophage ...
fgrieu's user avatar
  • 141k
3 votes

Is there a quantum-safe time lock?

A similar construct to a time-lock puzzle is a verifiable delay function. They have a similar notion of "inherent sequentially". They have an unrelated "public verifiability" property which you do not ...
Mark Schultz-Wu's user avatar
3 votes

Create a time capsule using a Word processor

I know no feature like this built into any word processor. And, despite work on so-called time-capsule cryptography, we know no practical[*] way to implement one without relying on trusted hardware or ...
fgrieu's user avatar
  • 141k
3 votes

Slow encryption (or reverse time-lock)

One obvious way (which is a variant of the normal time-lock encryption technique) is to do RSA encryption, with a truly huge $e$. That is, to encrypt, you compute $M^{3^\lambda} \bmod N$; by making $\...
poncho's user avatar
  • 147k
2 votes

Is it possible to make time-locked encrytion algorithm?

Setting aside the issue of nuanced time dependency (if a message can be decrypted at time $t$, how will you forbid anyone from using all the information that was available at time $t$ to decrypt it at ...
JamesTheAwesomeDude's user avatar
2 votes
Accepted

Sequential public key generation with secret private keys?

Yes, this is indeed possible. A scheme with such properties is e. g. used in Bitcoin's HD (hierarchical deterministic) wallets. The scheme was introduced in BIP32 (Bitcoin Improvement Protocol) and ...
raisyn's user avatar
  • 481
2 votes
Accepted

Time-release Protocol Implementation

Tibor Jager (author to the first paper linked in question): "There is no implementation yet. Given that there are no really efficient Witness Encryption schemes yet, the construction so far is ...
Hadus's user avatar
  • 141
2 votes
Accepted

Time locked cryptography using Bitcoin difficulty param and/or smart contract?

Those are indeed the main known solutions. Note that your solution A has been explored in the cryptographic community, this paper is an example of a theoretical work on the subject, but I think there ...
Geoffroy Couteau's user avatar
2 votes
Accepted

Keygen with timelock encryption so that the secret key is hidden from everyone?

The scheme proposed in the question looks reasonably possible but might require getting some details right and thinking more carefully about the desired security guarantees. On the other hand, it is ...
Marc Ilunga's user avatar
  • 3,188
2 votes

What is the progress on the MIT LCS35 Time Capsule Crypto-Puzzle?

Amazingly enough, the puzzle was solved a few weeks after @TacticalCoder got an answer, on May 10, as described at https://www.cryptophage.com. Their solution worked in 2 months, rather than nearly 4 ...
nealmcb's user avatar
  • 570
2 votes

Is there a quantum-safe time lock?

There is an interesting time lock technique known as 'delay encryption'. This is based on isogenies of supersingular curves and pairings. As we know, Supersingular Isogeny curves are one of the ...
Gokul Alex's user avatar
1 vote
Accepted

Is there a quantum-safe time lock?

No, not yet. Let: "time" mean the total amount of computations, and "parallel time" mean the minimum amount of sequential computations In order to meet the practical requirements for a puzzle that ...
Nic's user avatar
  • 498
1 vote
Accepted

Assumption of difficulty of attack in restricted short time

One area that tries to address such questions is fine-grained cryptography [DVV]. Here the working assumption is that the protocols should be secure "against adversaries with an a-priori bounded ...
ckamath's user avatar
  • 5,188
1 vote

Could time lock encryption be implemented through indistinguishable obfuscation?

Time-lock puzzles can be built from indistinguishability obfuscation through succinct randomised encodings: see the work of Bitansky et al. [BGJ+,BGL+] for more details. [BGJ+]: Bitansky et al. Time-...
ckamath's user avatar
  • 5,188
1 vote

Time and location locked vault protocol?

I saw this interesting question a long time ago. Today I decided to answer it. I think practically this can't be very accurately (in time and location) solved and will never be totally secure because ...
tur11ng's user avatar
  • 962
1 vote
Accepted

How can I generate a deterministic evenly distributed random number in a blockchain

You are looking for a Verifiable Delay Function (VDF). Roughly VDFs are functions which are hard to parallelize but easy to verify (for some sense of easy). One simple example is to just iterate a ...
Tjaden Hess's user avatar
1 vote

Time-based Crypto

If the period for which the message can't be read it is < 2 weeks, then yes. This forum is littered with proof of work time based cryptography so I won't rehash them. In reviewing the questions /...
Paul Uszak's user avatar
  • 15.4k
1 vote

Is it possible to make time-locked encrytion algorithm?

You can use drand, which is backed by companies like cloudflare. Here is a demo and web demo
Fawaz Ahmed's user avatar
1 vote

Is it possible to make time-locked encrytion algorithm?

I wonder why SNARKs and computational locks as presented e.g. by Liu, Jager, Kakvi and Warinschi in their paper how to build time-lock encryption haven't been mentioned yet. SNARKs / zk-SNARKs and ...
omni's user avatar
  • 111

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