Questions tagged [key-image]

Questions about key images including how they are computed and how they are used to prevent the double spending of Monero

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How is an input amount proven to be legitimate? [duplicate]

Let's say I received 1 XMR and now have an output for that, but nobody can see that this output is worth 1 XMR but me, right? What is preventing me from using this output as an input for another ...
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Ring signature and key images for dummies?

So I think I understand the Pedersen commitment math on the curve to hide amounts, but I'm struggling to understand how ring signatures obfuscate your transaction even further. If only one set of the ...
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In the Ring Signature Process, which one of my keys is used for signing?

I don't get the Ring Signature process. I tried to read about that but I don't understand what is happening in a more technical way. I'm specially confused about which one of my "Public Keys"...
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How do I get the key image for a particular address in monero-wallet-cli? [duplicate]

I want to run sweep_single unimportant index=1 keyimage destinationAddress. For this I seem need to have a key image for the address that I'm going to spend from so that I can pass it to sweep single ...
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Logic behind selecting even square root for fe_sqrtm1 = sqrt(-1)

That is the logic behind selecting even square root for fe_sqrtm1 = sqrt(-1) x = sqrt(-1) x = 547cdb7fb03e20f4d4b2ff66c2042858d0bce7f952d01b873b11e4d8b5f15f3d x = ...
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How does Monero verify a tx outputs key image?

I'm new to Monero and I'm trying to get to grips on transactions compared to BTC. What I'm trying to understand is - what prevents a transaction using a completely random string for 'x' within I = xHp(...
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How to compute ringct multisignature key images? (Disambiguation of MRL005)

I'm looking at the multisignature scheme provided by MRL005 Section 4.4, and some things are unclear to me. I've attached a picture below of the expression for which I'm seeking some clarification. ...
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What is the size of the set of spent key images in Monero?

For research purposes, I want to know the following: What is the exact size of the set of already spent key images and how it can be checked? Do we need to download the Monero blockchain to get the ...
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Problems in generating LSAG KeyImage

I am trying to generate LSAG KeyImage by myself in C which is K̃ = kπ*Hp(R). And I take result of MiniNero as a reference.. def test_keyImage(): private_key = "...
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Why is a key image xHp(P), and not something simpler like Hs(x)?

I understand how ringCTs work and know that they require a key image of the private key of the input that is actually being spent. How is this created? Couldn’t you just hash the private key of the ...
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Function ge_fromfe_frombytes_vartime() step by step explanation?

Could somebody please explain how this function works step by step? Why: I am programming the Monero wallet functions on a quite limited platform with only some inbuilt cryptographic primitives. I ...
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Help needed with calculating a key image

I am working on monero synchronization on an ARM cortex m4 microcontroller and I got stuck with computing key image. As a testing data I created a fresh wallet A and a fresh wallet B. I funded wallet ...
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Sent some monero with the cli using the transfer command. How can I get the key to view proof that I sent it using an monero explorer?

I did a transfer using the cli and now I want to view it in the https://xmrchain.net explorer. What do I need from me to decode the outputs so I can prove that I sent it? And what commands do I need ...
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How is the number of key images for a transaction selected?

I see that there are a few transactions that have many key images for each of the 11 ring members. But there are also a few with a lesser number of key images. How does this happen?
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Key Image and Ring Member

When were counting the number of ring signatures for a certain transaction do we count the number of key images or ring members of each key image?
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Does the Key Image leak privacy information?

If I Sign two different transactions with the same private key and send it to the same node. Would this node now be able to know which member of the ring is trying to sign? As I believe the public ...
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The entire lifecycle of an XMR transaction with RingCT

I'm trying to understand the data structure in monerod and create a simple workflow for a transaction's life cycle. It doesn't look like this has been done post-RingCT activation, and I see a lot of ...
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Can monero include actual spent input as previous transaction output?

Let's take we have two transactions. In the first transaction, it has 1 input with zero mixins and 3 outputs(stealth addresses). The second transaction has 1 input with one mixins and 2 outputs. Here ...
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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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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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3 votes
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131 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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wallet cli v0.12 : " Error : Failed to import Key images"

I've already created some view only wallet using --generate-from-view-key and importing key images, but today i've an issue doing this last step with Wallet cli v0.12. I've the following message when ...
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4 votes
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494 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 ...
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Is it easily provable by a third party that the key image used in a transaction is associated with the spent output without revealing the (P,I) pair?

What I'm getting at is I'd like to know how the Monero network can know that a key image used in a transaction is not either forged (probably an easy answer) or created from a different output owned ...
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9 votes
1 answer
874 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 ...
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9 votes
3 answers
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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 ...
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4 votes
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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 ...
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5 votes
3 answers
955 views

Is making a key image public equal to giving the monero in that output away?

So I read about proving your balance to an auditor, and someone suggested that you can share your view key, exposing all outputs that you received on that address. If you then give out all key images ...
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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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3 votes
2 answers
165 views

How can I check if a key image has been imported into a view wallet?

How can I check if a key image has been successfully imported into a view wallet, particularly a cold wallet that has never spent any of the funds it has received?
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10 votes
1 answer
191 views

Is it safe to share my key images with other people?

Let's say I run a charity that wants to show people how much money comes in and out of my Monero wallet. If I export the key images, is it safe to publish them on my website, or does doing so open up ...
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7 votes
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509 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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bad balanced CURRENCY_BLOCK_GRANTED_FULL_REWARD_ZONE constant

I have seen several Boolberry users report a wallet and daemon error similar to this one: Wallet: Error: transaction was rejected by daemon with status "Failed" Daemon: Transaction with id= ...
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17 votes
3 answers
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What is a key image?

When a transaction is made with monero there is a 'key image' in the transaction info. what is this exactly? is it like the diffie-hellman exchange to create the one time addresses?
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5 votes
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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 ...
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1 vote
1 answer
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Trezor firmware, private view key, key image and privacy

It is my understanding that the Monero trezor firmware uses the private view key. This might lead to some privacy concerns. I have read that key image can be used to check balance of a paperwallet. ...
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4 votes
1 answer
532 views

What are the "ingredients" of a key image?

This is a scenario I've come up with to help me understand key images. Let's say I have Wallet 1 and Wallet 2. Wallet 1 has TXO A and TXO B. I send TXO A and TXO B as inputs to Wallet 2. TXO B was ...
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5 votes
2 answers
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Can the import\export key images command can be used to check the balance of a paperwallet?

The import/export key images command can be used to check the balance of a view only wallet. But is there a way to use it to check the balance of an already set up Paperwallet? Is it possible to get ...
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7 votes
3 answers
238 views

Does publishing view key and key images give the auditor the information on where I sent the funds?

I see here that it's possible to provide information to an auditor to prove the balance at a certain point in time (block height). Would this tell the auditor to where were the funds were sent? Based ...
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19 votes
1 answer
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Can I fake a balance by giving the view key to an auditor but omitting some transactions and key images?

The viewkey can be used to see the outputs sent to my address, but not the outputs I generate when sending monero. If I need to know the balance I also need the private spendkey. It is suggested that ...
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