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Questions tagged [cryptography]

Practice and study of techniques for secure communication in the presence of third parties called adversaries

4
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1answer
56 views

Who Generates parameters G & H for Pedersen commitment in Monero?

Who (which party) generates parameters G & H for Pedersen commitment in Monero? I mean for a confidential transaction in Monero, pedersen commitment is required which has parameters G & H ...
1
vote
1answer
40 views

What makes decoding the total sent amount using the viewkey potentially inaccurate?

When using the 'decode outputs' on moneroexplorer for a TX that I sent, I get this warning when it (correctly) estimates the amount that I spent: Possible spending is: spent amount (tx fee included)...
3
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1answer
70 views

How is Keccak calculated in Monero?

I am reading the monero's implementation of Keccak (used as first part of slow_hash) in src/crypto/keccak.c I have found that it is a Keccak-256 (with b=1600, c=512, r=1088) and "output" of 1600 bits ...
2
votes
1answer
61 views

What are the hex representations of the small subgroup curve points on Ed25519?

Monero uses Ed25519, which has a cofactor of 8. This means the curve has a prime order l = 2^252 + 27742317777372353535851937790883648493 and the total number of possible points on the curve is 8l. ...
1
vote
1answer
47 views

Is the connection over Tor between client and remote node safe?

I'm using torsocks to connect my CLI wallet to a remote node (geo.node.moneroworld.com:18089). I don't need a high level of anonymity, but I would like to understand what information is at risk. For ...
0
votes
1answer
50 views

How do I multiply 2 public keys?

I want to make DH-like key exchange calculating something like this: b = H(b0B1B2) But the problem is multiplication between two ec-points is not defined on ec-curve. I know monero makes some ...
5
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1answer
91 views

Where can I learn about the cryptography used in Monero? [duplicate]

What papers should I read to understand the mathematics behind Monero?
0
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1answer
95 views

Calculating subaddresses

The PR for subaddresses and MRL-0006 say that the value m is calculated as: m = H_s(a, i) or H_s(a || i) I have found another question attempted to find the answer to my same question, however I am ...
5
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2answers
170 views

Understanding MLSAG in Monero transaction

This is a followup question to Understanding the structure of Monero transaction with emphasis on the MLSAG part. Here's the transaction's structure again given with print_tx ...
3
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1answer
107 views

How to convert monero's curve25519 basepoint to bouncycastle

This is how to get the curve25519 basepoint in monero (use js console at https://xmr.llcoins.net/) > var identity = "0100000000000000000000000000000000000000000000000000000000000000" > var base ...
6
votes
1answer
159 views

Transaction structure: Question about ecdhInfo

This question by kenshi84 shows how the pseudoOuts and outPk fields can be validated by anyone (without knowing any of the private keys involved), by checking that sumIn === sumOut: > var H = ...
3
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1answer
75 views

How is m calculated when generating subaddresses

In Kenshi's notes in the subaddresses PR it says that when generating subaddresses m = Hs(a || i) and i is just the index of the subaddress. so if a is the secret view key "...
3
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1answer
141 views

Using Monero as proof of funds

I'm writing an article about the future of Healthcare. I wondered if it was possible to use Monero to make a proof of funds. For example: the hospital wants to know that I can pay for the medical care ...
5
votes
1answer
48 views

(Non-ring) Wallet signatures

I am reading about ECDSA and EdDSA. I was wondering what the Monero void crypto_ops::generate_signature signature is based upon. From the code, I see that the math to generate one is k = rand() t3 = ...
3
votes
1answer
95 views

Discrepancy CNS006 and CryptoNote whitepaper one-time key generation

CryptoNote 2.0 uses P=Hs(rA)G + B for the generation of a one-time key. CNS006 seems te change this to P=Hs(rA||n)+B, where n is the transaction index (encoded as varint). Why is there this ...
7
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1answer
375 views

Stealth addresses: where do they come from?

I wonder what the origin of stealth addresses is. I learned that they were introduced for BitCoin, by Peter Todd. However, I cannot find any literature describing or analysing the specific ...
9
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1answer
429 views

Are Confidential Transactions in Monero perfectly binding or hiding?

Bitcoin contributor Pieter Wuille recently commented on Reddit: Bulletproofs and the Pedersen commitments they operate on are perfectly hiding, but not perfectly binding. This roughly means that ...
6
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1answer
372 views

Is CryptoNight the hash function which plays the role of the “random oracle”?

Is CryptoNight the hash function which plays the role of the "random oracle" in the random oracle model under which certain properties of CryptoNote are mathematically proven in the original paper? Or ...
3
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1answer
216 views

Scratchpad Initialisation : What is the input to Keccak?

So this is probably a question I should be able to find the answer to easily but I am stumped. In the documentation for cryptonight the part on scratchpad initialization says: First, the input is ...
7
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1answer
344 views

How do key images really work?

I have the following questions regarding the equation I=xHp(P): What is the hash function Hp? How can we know that Hp(P) is a point on the Ed25519 curve? Or is it not? Is the value I published with ...
6
votes
2answers
378 views

How do I manually decode outputs?

I'm currently coding a small Monero tool just to better understand how it all works. I already implemented address-generation from scratch (thanks to luigis address test page) and the next step is to ...
7
votes
1answer
2k views

What cryptography primitives/concepts, other than the basic ones, does Monero use?

The following are the "basic" cryptography primitives/concepts, taught in all beginner textbooks on cryptography: symmetric encryption (stream and block ciphers. AES, etc.) asymmetric public-key ...
8
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3answers
3k views

How does the recent patched key image exploit work in practice?

For more info https://getmonero.org/2017/05/17/disclosure-of-a-major-bug-in-cryptonote-based-currencies.html This has been patched months ago and was never exploited which can be proven by running a ...
5
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3answers
510 views

Can a One-Time public key be used for more than one payment?

If I understand correctly, every new payment will ideally have a different one-time public key for increased privacy. However, could a one-time public key receive Monero more than once (as in ...
2
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0answers
58 views

Cryptonote one time use view key

Would be possible to have a one-time view key where it would expire after one use or a specific time has been reached? We assume that this is using the blockchain thus it cannot be modified. What I ...
3
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0answers
57 views

Determining the real transaction/balance with view key only

An open source web lightwallet was posted on Reddit the source is https://github.com/moneroexamples/openmonero. It would be able to check the balance of your wallet with only the address and view key (...
5
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2answers
162 views

Key-image generation: What does p signify in I = xHp(P)?

According to the CN whitepaper key image I is generated thusly: I = xHp(P) I understand P is the one-time public key for the transaction, x the corresponding private key and H a deterministic hash ...
5
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3answers
334 views

How does RingCT work with / without coefficients?

I was trying to get more information on how RingCT works, I found the thread I linked to below here on the stack exchange. In the other thread, the most upvoted answer explains it as a coefficient, ...
3
votes
1answer
38 views

How can I verify the SHA256 hash of 0.10.3 “Wolfram Warptangent” on FreeBSD?

How can I verify the SHA256 listed in this GPG-signed message for the official Monero 0.10.3 release matches the file that I downloaded for FreeBSD, 64-bit?
4
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1answer
88 views

How can I verify the SHA256 hash of 0.10.3 “Wolfram Warptangent” on macOS?

How can I verify the SHA256 hash published for the official 0.10.3 "Wolfram Warptangent” release matches the file that I downloaded for macOS, 64-bit?
3
votes
3answers
1k views

How can I verify the SHA256 hash of 0.10.3 “Wolfram Warptangent” on Windows?

How can I verify the SHA256 hash published for the official 0.10.3 release matches the file that I downloaded for Windows, 64-bit?
6
votes
3answers
199 views

How can I verify the SHA256 hash of 0.10.3 “Wolfram Warptangent” on Ubuntu?

How can I verify the SHA256 hash published for the official 0.10.3 release matches the file that I downloaded for Linux, 64-bit?
1
vote
1answer
55 views

Why does the SHA512 code include numbers ending in ULL?

The sha512-blocs.c file contains five blocks like these: F(w0 ,0x428a2f98d728ae22ULL) F(w1 ,0x7137449123ef65cdULL) F(w2 ,0xb5c0fbcfec4d3b2fULL) F(w3 ,0xe9b5dba58189dbbcULL) F(w4 ,...
6
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1answer
371 views

Can someone walk me through a simple example to explain how RingCT works?

Original: https://www.reddit.com/r/Monero/comments/5irg81/questions_regarding_the_cryptography_behind_ringct/ I just read the RingCT paper, and there are a couple things that could use some clearing ...
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0answers
70 views

BLS Signature Aggregation

Would signature aggregation as an alternative to pruning be possible / desirable with Monero? As far as I understand it, it's a way to compress hundreds of tx into a single hash.
4
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1answer
117 views

How do ringct transactions use previous non-ringct outputs in a ring signature with ringct?

How will ringct transactions use non-ringct outputs to use in a ring signature? Is there any trick that gets them to work together with ringct or is it pretty simple and I am missing something?
7
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1answer
376 views

What signature prevents me from spending others' coins?

In passive mixing, the monero wallet finds n other parties and forms a ring signature that proves the signer is one of the parties in the ring, and hence entitled to spend from one of the accounts ...
7
votes
1answer
226 views

What was the problem with ASNL forgery?

For background there is https://nickler.ninja/blog/2016/12/17/a-problem-with-ringct/ and this problem had been fixed before this post was made by changing ASNL to borromean signature. For background ...
8
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3answers
380 views

In ringct, how are the range proofs kept separate from the pedersen commitments in a transaction?

Are the range proofs and pedersen commitments part of a transaction? Or are they not kept in a transaction at all?
9
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2answers
149 views

Can Monero's privacy features be integrated into (copied) by bitcoin?

Can Monero's privacy features be integrated into (copied) by bitcoin? If so, to what degree given the current political gridlock? By the way, I'm a true believer and I'm setting up a full node as I ...
5
votes
1answer
389 views

What other benefits does Cuckoo Cycle have over cryptonight, is it quantum computer proof?

I have read Which reasons were discussed for potentially changing the proof-of-work algorithm? but aside from being more asic 'resistant' and faster to verify what other reason should monero change ...
5
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2answers
329 views

Why does Monero use keccak over something like sha-256?

Keccak uses a sponge function which is cool but what benefits does keccak have over sha-256 for cryptography operations in the code? thanks
5
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1answer
687 views

Will quantum computer break ring signatures?

I knows quantum computer breaks elliptic curve math but what about ring signature? thanks
9
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1answer
857 views

What are Borromean signatures?

For more background info visit GitHub or Bitcointalk It looks like borromean signatures are going to be replacing schnorr signatures in the RingCT hardfork. What does this mean for Monero and RingCT ...
5
votes
1answer
183 views

What alternative cryptography could be used in the future to protect Monero against quantum computers?

I know most cryptography Monero uses relies mostly on EC crypto which would be easily broken by a quantum computer powerful enough. What options does Monero have in the future to protect itself?
6
votes
1answer
181 views

How were Monero elliptic curve constants chosen?

In the cryptonote paper review, there was a mention about not knowing how the constants were calculated, is there anyway to verify these constants are 'safe' or change them to something 'better'? ...
3
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1answer
111 views

What cryptography does Monero utilize?

Just looking for a brief explanation of what cryptography is used and where/how it is used in Monero. Thanks :)
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0answers
186 views

Security risk due to bad random number generator when creating transactions

I've noticed such risk mentioned in this answer to another question, where a presentation (page 28) by Nicolas T. Courtois, studying Monero cryptography, was referred to. I'm interested to better ...
5
votes
1answer
208 views

What is the deterministic hash to EC function used to construct the key image?

Ring signatures alone would allow double spending, so Monero (as a result of following the CrpytoNote whitepaper) has to use a 'key image', which is the same across identical transactions and hence ...
5
votes
1answer
60 views

Literature suggestions to understand the cryptography used in Monero?

For a computer scientist familiar with theoretical aspects of the field and a solid understanding of mathematical foundations, but no background in cryptography, what are recommended books or papers ...