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Questions tagged [privacy]

Questions related to data and smart contract privacy. For questions related to user anonymity, use [tag:anonymity].

1
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1answer
17 views

Parameter's Value visibility

Is the value of a contract's method's parameter visible on blockchain? On Etherscan, in the tx information there is an Input Data field, which details says The binary data that formed the input of ...
2
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1answer
40 views

How privacy can be ensured in smart-contracts?

When a smart-contract is created following an agreement between two entities, how the state of that contract (data) can be kept secret to only the two contractors? I heard about Quorum, but how ...
0
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1answer
30 views

Is data inputted as a parameter for a smart contract function visible?

Let's say I have something like this: bytes32 person; function registerPerson(address _person) public { bytes32 x; x = sha256(abi.encodePacked(_person)); person = x; } For privacy reasons, ...
0
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1answer
27 views

Implementation of privacy in blockchain

How can we see transactions in a particular block of Bitcoin, if they are encrypted and only Merkle root of transactions is stored on the blockchain. I think in that way we should be having an ...
16
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2answers
566 views

zk-SNARKs vs. Zk-STARKs vs. BulletProofs? (Updated)

zk-SNARKs, Zk-STARKs and BulletProofs are three major zero knowledge proofs to provide privacy for the blockchain technology. If we can compare them, (1) Bulletproofs and Zk-STARKs require no ...
1
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1answer
29 views

Save temporarily-shareable private data using Quorum

Can we use Quorum (or any other Ethererum variation) to save private data that can be shared with other parties for a temp period? The use case is that: A patient can share his medical data that is ...
1
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2answers
32 views

Is there any way to fund a new account privately via a randomising pool?

It isn't currently possible to create a new HD wallet account and privately fund it, is it? I'm aware of this thread, but I'm not asking about SNARKs. Instead, I'm curious if there's any way to send ...
0
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0answers
21 views

chaindata - sharing identifier data across owners

Suppose, we want to store the tuple (studentId, libraryId, bookId, timestamp, action) on a blockchain where, studentId identifies a student belonging to a library. libraryId identifies a library that ...
2
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1answer
196 views

An example on using “zk-SNARK” in “smart contract”?

I read this article: https://media.consensys.net/introduction-to-zksnarks-with-examples-3283b554fc3b However, it's not clear to me a function such as zksnarkverify has been already implemented in ...
3
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0answers
76 views

Updated: Is it possible to hide the sender or receiver of transactions by “zk-SNARK” or “Bulletproofs”?

To support the user privacy, is it possible to hide the sender address or receiver address of transactions by "zk-SNARK" or "Bulletproofs" ? Or we’ll be able only to hide the value that is mapped to ...
0
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0answers
40 views

zk-SNARK use cases in blockchain (except payment)?

Is there other examples of using zk-SNARK for supporting "private transactions" except Zerocoin or Zchach ? (For example, is it possible to use zk-SNARK for health data ? or any other use cases in ...
1
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2answers
31 views

Is data stored in string form in smart contracts publicly readable?

As a beginner, I wrote the contract below for learning purposes, aiming to create a "Safe Messaging System": pragma solidity ^0.4.24; contract SafeMessage { string message; string password; string ...
1
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1answer
65 views

Quorum privateFor visibility

Our current project requires that the recipients of a private transaction are unknown to the rest of the network. So my question is: is the privateFor field dropped before sending the transaction to ...
3
votes
1answer
34 views

How to use key derivation and 'coin selection' to increase privacy, like in Bitcoin?

In Bitcoin, you can have increased privacy by never re-using addresses. A single private key can generate many addresses if you are using a key derivation scheme. In Ethereum, instead of UTXOs you ...
0
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2answers
91 views

Which wallets lets you generate multiple ethereum addresses?

Is there a wallet that lets you generate multiple ethereum wallet addresses? I don't like the fact that I only use one address and that everyone can see what I have. Or are there other ways to keep ...
2
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1answer
27 views

How to listen to inter-node communications regarding transactions

If I run a full node (say geth) in the Ethereum network, then the way things work out is that every node releases/ announces new transactions as they receive new ones. I'm assuming that my node must ...
1
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2answers
59 views

Is it possible to identify a smart contract if you know the byte code of it?

I am currently writing a master thesis about Ethereum. In the thesis, I develop a system to send data and do calculations with data on the ethereum blockchain with a smart contract. The system I am ...
1
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1answer
31 views

Is there a privacy token implementation in the works for Ethereum like Monero's Tari system?

With the recent announcement of being able to have privacy type tokens on the Monero blockchain. Is there a proposal on ethereum for something similar? The usecase of having a private ERC20 would be ...
1
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0answers
63 views

How to fund Ethereum address relatively anonymously? (breaking a link with an already established address)

I want to deploy smart contract. I just don't want people inspecting the code on Etherscan to see what crappy ICOs I've sent my ETH back in 2017... Some options coming to mind: use Shapeshift ...
3
votes
0answers
312 views

Ethereum facilitation for zk-SNARKs

There has been a lot of talk about leveraging zk-SNARKs to bring privacy features to the Ethereum Blockchain. My question is, how is Ethereum facilitating the verification of zk-SNARKs at the moment, ...
1
vote
1answer
89 views

Data privacy with block chain in health care?

I'm new to the concept of block chain and have only been reading about it the past four hours. I hear a lot of marketing and business folks tell me that block chain is the way of the future for data ...
0
votes
1answer
47 views

Privacy-preserving smart contracts: examples, tutorial, best practices?

I want to make a proof-of-concept about privacy-preserving smart contracts. I know it's uneconomical to use encryption with Ethereum smart contracts. Are there best practices about how to do that? ...
0
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2answers
186 views

How do I see the value of a string stored in a private variable? [duplicate]

I have read many times that sensitive data should never be stored in a transaction, but, specifically, how would the value of a state variable be read if marked private?
0
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0answers
15 views

Private/Encrypted information on the blockchain possible? [duplicate]

We have hardware (smart meter) that we wish to use as oracle to generate tokens (based on electricity produced). Currently we have a central address that matches the wallets (for the tokens to be ...
0
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3answers
140 views

Is it possible to obscure the owner of a non-fungible token?

Basically, I'd like to have unique records which can be transferred between parties without anyone knowing who owns a particular record until a transfer occurs, at which time only the recipient can ...
0
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0answers
16 views

Different contracts for different rating algorithms

I am working on a Rating System where, a given entity enters values for certain parameters. Then, a rating algorithm takes those inputs and returns a score between 1 and 10; higher the better. I want ...
1
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0answers
35 views

Share private data and prevent data forwarding

Let's say A has some private medical records of patients and B is a pharmaceutical company who wants to view medical records from A to find out the effect of a particular drug on the patients (run a ...
1
vote
1answer
183 views

Are the contents of ethereum storage private? [closed]

I know that the code is public, but is the contents of storage private?
1
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1answer
51 views

How can we make our variables private? [duplicate]

"Everything that is inside a contract is visible to all external observers. Making something private only prevents other contracts from accessing and modifying the information, but it will still be ...
3
votes
2answers
212 views

Is there a way to privately send ether?

Is there currently any way to privately send ether? If not, are there any plans in the future to implement any privacy features?
1
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2answers
57 views

Can other nodes in system see the state of my contract?

I created a simple contract which has a simple state with a single int. I gave it a value of 90 at the deployment time (constructor). Now I went to the particular block in Rinkeby, and I could see ...
0
votes
1answer
153 views

How do private members work?

The solidity documentation says that Everything that is inside a contract is visible to all external observers. Making something private only prevents other contracts from accessing and ...
1
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0answers
39 views

How would zkSNARKs reduce computation on Ethereum mainnet?

cmiiw, zkSNARKs mean that computations can be verified by a single node and therefore not executed by every node on the network-- link, and work is being done to include this feature in the mainnet. ...
0
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0answers
24 views

Is it possible to migrate your db(users login credentials) to ethereum private network?

I am thinking of migrating db to any of blockchain technologies for security purposes. I have to opt from hyperledger or ethereum private network. Is it good idea or any trades off I should be aware ...
0
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1answer
1k views

Tracing wallet IP address

I read about this privacy attack to the BTC network : https://bitcoin.stackexchange.com/questions/193/how-do-i-see-the-ip-address-of-a-bitcoin-transaction It is based on network observation from a ...
-1
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1answer
128 views

How To Send ETH without communing TX on blockchain (via Smart Contract)

Is there anyway to send some ether without committing transaction in blockchain using Smart Contract? Thanks.
0
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0answers
342 views

Is it possible to make ethereum private by default like how monero has it?

How would ethereum be made private and anonymous by default like how monero has it? Is it possible to turn an token into a fully private anonymous token by default?
1
vote
1answer
159 views

Is a battleships implementation feasible?

A bunch of people created a chess system that runs on the EVM: here. I'd like to make a similar game of battleships but there seems to be an apparent difference. In battleships, you can't know what ...
0
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0answers
112 views

Is there a strategy for keeping data “private” and then releasing it programmatically [duplicate]

I'd like to do the following: Have a smart contract with an IPFS link as part of the contract whose contents are in some way "private" or otherwise inaccessible At exactly one point in time, release ...
1
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0answers
187 views

Will people still be able to see my smart contract code if I make the functions private? [duplicate]

I am interested in knowing if someone can read the code for my smart contract after I deploy it to the live ethereum blockchain. If I make my functions private. The goal is to hide the code.
2
votes
1answer
107 views

How do existing applications on the Ethereum blockchain enforce confidentiality of data?

How do current applications on the Ethereum blockchain enforce confidentiality of data? I know that the state of a contract is visible to any node on the network. Does this imply that there are no ...
1
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2answers
1k views

Confidentiality in Blockchain

Can Blockchain miners see confidential transaction information? Since they have the public key, they decrypt the transaction for the purpose of verification. So if I am mining in Ethereum, I can tweak ...
4
votes
1answer
70 views

What can we tell from a contract's public address?

This is asked differently around but I haven't found an explanation as direct as I wanted to. I've read that all state variables in a contract are publicly visible (solidity docs). It's stated there: ...
0
votes
1answer
57 views

Maintain and even restore privacy when using cryptocurrencies

All things about cryptocurrency are very new to me; however, the more I learn the more exciting it is and the more possibilities I see as an application developer. I'm particularly happy to have made ...
6
votes
1answer
2k views

Should I create a new address for each transaction?

It's my understanding, when using bitcoin, it's advisable to generate a new address for every transaction. Is this also the case for Ethereum, and if so, how do I do this with Mist?
0
votes
1answer
264 views

Private ledgers on a Ethereum Blockchain Network

We are exploring one use case to connect a million customers with a bank. Since customers' transactions should be private to them, we want to understand whether we can have concept of private ledger ...
4
votes
1answer
510 views

Current state of zero knowledge proofs?

Are there any current proof of concepts or implementations of zero knowledge proofs in the context of smart contracts? If not how long until we can store private data on a public blockchain?
6
votes
1answer
1k views

Store secret data in contract [duplicate]

I know about the general open / trustless protocol of storing transactions. How would I approach a scenario here where I want to store some data in a contract on deployment, to later be retrieved by ...
2
votes
1answer
43 views

Revealing played value

I'm writing a smart contract where participants are asked to submit a value (1 to 1000000) in the submission period, and then reveal what that value is in the revealing period. In order to hide it ...
10
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3answers
4k views

Is there any way to hide a transaction?

Is there any way to hide a transaction on the Ethereum blockchain? Some blockchain have protocols that implement this by default, like Monero and Zcash. Is something similar possible on Ethereum?