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A ring signature is a group of cryptographic signatures with at least one real participant, but there is no way to tell which in the group is the real one as they all appear valid, while the key image prevents double spends.

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How does key images work when you create a transaction using two or more of your previously unspent transaction outputs?

I've read key images are the critical element in Monero to avoid double spends. I think I understand how it works when you are using only one of your previously unspent transaction outputs to create ...
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1answer
53 views

What keys are being used to create the key image and how is it verified?

So i'm trying to pin this down since yesterday and i simply cannot find a definite answer. Read dozens of posts and few papers specifically on this topic and while i developed a "belief" that it has ...
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1answer
68 views

Detecting the real output in ring signature

I have a strange question about the relation of P_i (stealth addresses in ring signature) with x (the one-time private key). Suppose Alice wants to spend P_1 with her spend private key (x) and we ...
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1answer
28 views

Does Monero use rfc6979 for signatures?

I came across a post stating that Monero uses the Borromean Ring Signature scheme to hide the amounts. So what signature scheme is used to sign the transactions?
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1answer
65 views

What does “rings used by outputs spent on Monero on a key reusing chain” mean?

Can you help me parse this sentence from the Shared RingDB page in the Monero GUI? This records rings used by outputs spent on Monero on a key reusing chain, so that the same ring may be reused to ...
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81 views
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63 views

Is a transaction from Exchange to Wallet to Exchange traceable?

Here is an example: Exchange1 --> Adr1; Adr1 --> Exchange2 Where Adr1 is a one-time subaddress. Now suppose that Exchange1 and 2 are corrupt and cooperate with a government to leak my information. ...
3
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1answer
64 views

How can I choose addresses to create a ring signature for a transaction

I am doing a project based on blockchain, and I found that Monero is a good candidate for my project because of its ring signature scheme. The scenario is that I would like to create a transaction ...
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2answers
152 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
133 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 ...
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0answers
67 views

MLSAG adaptation?

I understand that the main reason why the RCTTypeFull scheme is not applied to multi-input transactions is that the true signing keys in the MLSAG algorithm are on the same row, which impacts ...
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2answers
237 views

Ring signatures and the long view

Imagine the Monero blockchain has been around for decades. It is incredibly massive and the total number of outputs far exceeds the rate of new outputs being created. Can obfuscation acquired by the ...
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1answer
58 views

Commitments for RCTTypeSimple transactions

Looking at the code, and after reading a post on the subject, it looks as if transactions of type RCTTypeSimple (multi-input, RCT) get new commitments with new blinding factors for the inputs. Doesn'...
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1answer
93 views

How Ed25519 curve relates to Borromean Ring Signature scheme?

Is it correct to say that Monero private keys are generated using Ed25519 curve and then Borromean Ring Signature scheme is used to sign transactions? In other words, is Ed25519 curve "compatible" ...
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2answers
360 views

What all information we can gather from a Monero wallet address?

I am pretty new to this crypto currency. My question is that what all information can be found, if we only know a malicious user's Monero wallet address? Can I check this Monero wallet balance? If ...
3
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1answer
307 views

Can someone show an actual example of a Monero transaction that uses two distinct private keys?

Could someone show me an actual example of a single transaction formed from two private keys. Say I have 5 XMR in one private key, and 10 XMR in another, so there are two unique private keys. How do ...
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0answers
53 views

Can ring signatures be aggregated in blocks to save blockchain space?

Monero is using borromean signatures right now but would ring signatures be able to be aggregated like schnorr signatures to help save space?
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3answers
319 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, ...
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3answers
1k views

What's the point of ring signatures if stealth addresses hide the actual addresses anyways?

I understand generally how ring signatures work, but I also realize they are sent to and from stealth addresses, and so I'm curious why ring signatures are needed in the first place. Doesn't a sender'...
5
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1answer
189 views

Is there anyway to calculate how much privacy is gained by increasing the ring size of a transaction?

The default for wallets right now is 4 but is there a large benefit say using 15 or 20 over 4? Can this be measured? Bigger ring size will help obviously but after a while is it not kind of a waste of ...
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1answer
364 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
260 views

Difference between Monero and CoinJoin [closed]

How does Monero provide any additional anonymity for the sender over a CoinJoin transaction? I get that it provides anonymity of the receiver and the amount spent via stealth addresses and RingCT, ...
6
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1answer
99 views

Is there a tool that tells me if my transfer has been used by others in a ring signature?

Is there a tool that, given a tx hash and/or a specific output, can search through the blockchain to see if it's been used as input in other transfers? This would preferably not be a web service but ...
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1answer
111 views

Can an output be used as a decoy after it has been spent?

The title of the question is probably specific enough, but I'll give more color anyway. Here's a quick timeline. I received output A a year ago. In the last year, output A has been a decoy in 3 ...
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161 views

How are outputs chosen on the blockchain for ring signatures in a transaction?

Is there any criteria which outputs are chosen for a 'mixin' in a transaction?
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1answer
115 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?
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1answer
364 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 ...
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24 views

Is it possible to censor a transaction in Monero? [duplicate]

Would it not be impossible to do censor because of how ring signatures work and not knowing what a transaction is for or where it is going? maybe i am missing something. thanks
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1answer
218 views

If I send two transactions to the same recipient, can they infer the true sender?

I send two transactions to the same recipient. The two sets of mixins used to generate the transactions would each include my public address. Is the recipient then able to reasonably infer that my ...
5
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1answer
678 views

Will quantum computer break ring signatures?

I knows quantum computer breaks elliptic curve math but what about ring signature? thanks
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0answers
65 views

Impact of Topological data analysis on Monero

What is Topological data analysis? Can it be used to study the Monero blockchain and degrade the privacy of transactions as claimed by Gary Le in the interview referenced by this answer?
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2answers
282 views

Could Monero implement zk-SNARKS in the future?

At the moment ring signatures are more eficient than zk-SNARKS, but as fluffypony already comment, probably any cryptocurrencie in the future will use this technology. Can monero implement zk-SNARKS ...
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1answer
298 views

What are MLSAGs, and what is their significance for Monero and/or RingCT?

I've seen MLSAG mentioned in a couple places. I believe it has to do with the "signature" part of "ring signature," but I'm otherwise clueless. Can anyone provide more information?
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1answer
475 views

Blockchain syncing and transactions verification

Recently I updated to version 0.10, but that wasn't an easy process. It took too long to go over my old blockchain and make it compatible with the new client, so I aborted that (iirc there was no ...
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2answers
76 views

Obfuscating the output as well?

This is just a random idea with no technical backing: with RingCT the input is obfuscated, but everyone still knows that the output destination holds the money. Is there any possibility of also ...
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1answer
352 views

Ring signature and blockchain analysis

I'm struggling to understand how ring signatures protect against blockchain analysis. Each time a transaction is made on the Monero blockchain some outputs already present on the blockchain are used ...
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2answers
229 views

When you sign a Monero transaction, are you signing a hash?

When you are signing a Monero transaction, do you sign the transaction itself, or do you hash the transaction and then sign that?
13
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1answer
438 views

Could Monero help me to implement a safe election for a small group of students?

The problem I am in charge of implementing a secure, secret election for a small group of students on my school. I have a list linking valid student IDs to emails, and I want each one of them to vote ...
3
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1answer
101 views

Help with sending on MyMonero

I just sent 6.9 monero from MyMonero, but it showed up as taking 10xmr out of my account instead of 6.9. On the receiving end it shows 6.9xmr as well. Where did the other 3.1 go?? Is that a "fee" ...
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1answer
201 views

Ring signature with sublinear size increase

The Wikipedia article on Ring signatures states that CryptoNote implements O(n) ring signature scheme by Fujisaki and Suzuki in p2p payments to achieve sender's untraceability. More efficient ...
4
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0answers
151 views

With RingCT, could an adversary get into a bunch of ring signatures to decrease privacy? [duplicate]

Let's say I want to deanonymize Monero. What if I create a ton of RingCT outputs, such that, say, +99% of them are mine. Since amounts don't matter with RingCT, it can be very small amounts (like one ...
6
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1answer
152 views

Are RingCT transaction bigger than an average ring signature transaction?

Are RingCT transaction bigger than an average ring signature transaction? If yes how much bigger?
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1answer
161 views

Mixin 0 (mixin 1) transaction ban

Does the network still accept mixin 0/1 transactions? Did Poloniex update their transactions to use a higher mixin?
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2answers
164 views

CryptoNote features in other cryptocurrencies

How many CryptoNote based currencies exist today? Have ring signatures appeared in any cryptocurrencies that are not based on CryptoNote? How many CryptoNote coins are not using a CryptoNight based ...
5
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1answer
200 views

Does Monero/the CryptoNote Protocol support multi signature wallets?

I did not find a question directly asking for multi signatures and Monero. Right now there doesn't seem to be support for multi signatures in Monero. So I want to know if it is technically feasible ...
11
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1answer
278 views

Are there more cryptocurrencies based on the cryptonote protocol? If so what are the main differences?

I read a bit about the history of Monero and how it forked away from bytecoin/bitmonero in 2014. I also remember that there was another currency using the cryptonote protocol called "Boolberry" at ...
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2answers
254 views

Spam attack to gain control of many outputs and undermine privacy

Would it be possible for an attacker to send many transactions to himself with the goal of gaining control of many outputs for the purposes of deanonymizing transactions of others (using low mixins ...
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1answer
242 views

How was the faulty ShadowCash implementation of ring signatures repaired in February 2016? [closed]

The cryptocurrency ShadowCash uses traceable ring signature to anonymize the sender of a transaction. However, these were originally implemented incorrectly, resulting in a partial de-anonymization of ...
16
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1answer
2k views

What is RingCT and how does it compare to Confidential Transactions?

What is RingCT and how does the addition of Ring Signatures enhance the privacy properties of RingCT compared to Confidential Transactions as designed by Greg Maxwell? https://people.xiph.org/~greg/...
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2answers
110 views

What level of cryptographic review has the current Monero protocol received?

What are the backgrounds of the members of the Monero Research Lab? What amount of known peer review have their publications received? Independent of Monero itself, how much Cryptographic review has ...