Questions tagged [privacy]

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

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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 ...
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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 ...
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146 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.
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414 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?
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196 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 ...
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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.
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1answer
115 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 ...
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3answers
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 ...
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1answer
77 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: ...
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60 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 ...
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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?
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296 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 ...
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1answer
545 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?
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2k 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 ...
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1answer
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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 ...
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5k 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?
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1answer
156 views

Is Ethereum blockchain public?

I have some idea of a smart contract, that based on private user tokens which stored in contract state. Every user can set his token by sending transaction to contract. But it is not secure if every ...
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Will forthcoming ability to make transactions private hide gas usage and mining information?

I understand that people are working on allowing for more private transactions on the public Ethereum mainnet. This would involve hiding (at the very least) the from, to, value and probably input ...
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1answer
483 views

Is the content of a function and the data in a smart contract publicly readable?

When I create a smart contract with some functions in it, I know anyone can execute those functions. My question is; can anyone also read the source/logic of those functions? And I've got the same ...
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1answer
203 views

Would be possible to hide a function execution with zkSNARKs?

I read that with an hypothetical integration of zCash/zkSNARK with Ethereum, it would be possible to hide the sender, the receiver and the value of a transaction. My question is if would also be ...
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760 views

Hiding variables in Solidity [duplicate]

What is the best way to encrypt and decrypt a variable in Solidity so only the msg.sender and contract can see that variable?
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1answer
724 views

How secure is this Rock Paper Scissors smart contract?

This contract has been out for a while (it's not mine). I wonder how secure it is. I understand encrypting & revealing process there, but what strikes me more is: When player1 calls method play ...
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5k views

Privacy of smart contract? How can one implement “private” smart contract on Ethereum? [duplicate]

Based on my current reading, I understand smart contract as a code visible and runnable on the whole blockchain. The smart contract code could be published by author, and everyone can verify the code ...
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368 views

When a smart contract is deployed, is its source code publicly viewable?

When a smart contract is deployed to the blockchain, is the source code then publicly viewable to all participants? For example, what you see here in Etherchain. I am aware that there are some ...
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1answer
1k views

Ethereum Authentication/Authorization

Lately I've been thinking about how to integrate Ethereum with other non-Ethereum systems. Would it be a bad idea to import and Ethereum keypair into an external (mobile/desktop) application, which ...
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1answer
258 views

Unlinkability between transactions to a smart contract

I am trying to develop an application using Ethereum and it needs to have transactions which are not linkable. I read an article by Vitalik Buterin, which speaks about it. He speaks about something ...
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1answer
964 views

Accessibility of public variables

If I have a public state variable, does this mean that other contracts can access or even change its value? I have made a cryptocoin from here and all variables are declared as public, so I am ...
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1answer
2k views

Who can access private state variables?

I was reading solidity Docs and everything made sense until I got to this: What are external observers? Is it clients listening for events or is it anyone who has access to web3 api? For example, ...
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135 views

Where can I find the snarkverify precompile (opcode) implementation in parity and the example coin mixing contract that utilizes it?

With the recent announcement of zkSNARKs support and the ZoE (ZeroCash over Ethereum) mixing contract (https://z.cash/blog/zksnarks-in-ethereum.html) Where can I find the mentioned parity branch and ...
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1answer
334 views

using indistinguishability obfuscation to ensure smartContract privacy

we all know the probelm of the public aspect of smart contract that harness the code privacy, do you think that APPLYING indistinguishability obfuscation to secure smart contract code resolve this ...
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2answers
213 views

Confidential value transfers

Is there currently any way to do confidential transactions with Ethereum for a custom token? If not, is there any work/research being done on how this might be possible?
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2answers
5k views

Solidity functions - private visibility

Is the following function parameter (string name) only visible to the owner contract itself? function myFunction(string name) private returns (bool) { return true; } So nobody can read / see ...
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1answer
470 views

How can I configure Ethereum to run over Tor or I2P

If Tor or I2P support is not yet practical, is there a guide of best practices to help protect IP and other metadata?
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2answers
435 views

How Right to be forgotten can be applied with Dapps like Akasha?

As Akasha decentralized social network is ready to launch, I wonder how rights like "Right to be forgotten" can work as the blockchain never forget ?
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1answer
158 views

How easy is it to obtain sensitive information that's included in an Ethereum contract?

I'm trying to understand how publicly available and easy to access the information embedded in contracts is, in plain language. Am I able to query the contracts in the Ethereum blockchain, similar to ...
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3k views

Private info in an Ethereum smart contract

Is there any way to store info on a smart contract, and keep it a secret? If a contract has a state variable that is not public like: contract foo{ uint public publicVariable; uint notPublic;...
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4answers
1k views

With a ring signature mixer, will Ethereum transactions be completely anonymous?

I was reading the Serenity PoC2. The part quoted below grabbed my attention. Does it imply full anonymity for Ethereum transactions should I decide to use the ring signature mixer? Ring signature ...
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4answers
1k views

How to increase my privacy on Ether accounts?

What would be the best way, if any, that one could change their address/account in order to make themselves unknown or hard to identify by people they traded with? More specifically, if I send ETH to ...
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1answer
309 views

Is it possible to run a client behind an onion address?

It is possible to run a bitcoin client which only connects to onion nodes in the TOR network, like that: ./bitcoind -onion=127.0.0.1:9050 -onlynet=tor -externalip=ssapp53tmftyjmjb.onion Is something ...
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2k views

What are effective techniques to encrypt/decrypt data stored in a smart contract?

Rather than sending and storing plain text in a smart contract, the use case objective is to encrypt first and then subsequently access the data and decrypt at the point of use. What is the most ...
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1answer
642 views

What data will zk-SNARKs protect?

Implementing zk-SNARKs is planned in Ethereum roadmap, what data will be obfuscated? transaction sender and receiver? data in transactions? data stored in contracts? variables and methods in ...
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3answers
1k views

Is there a point to hide Ethereum nodes with TOR?

From a privacy perspective, is there any point in trying to torify ethereum nodes? I know there's a script to do that in bitcoin, although doing so may ironically made the bitcoin node more ...
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3answers
907 views

How can we write a contract that relies on hidden information?

Since a smart contract can only access (public) information on the blockchain itself, how can I make a smart contract that relies on hidden / secret information? Are there any workarounds in this ...

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