IT Security Stack Exchange
IT Security Stack Exchange

Questions tagged [bitcoin]

BitCoin is a distributed crypto-currency. General questions about bitcoin, other crypto-currencies and their environment not directly relating to security are better suited for bitcoin.stackexchange.com

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If the bitcoin network was cracking bcrypt, what cost factor would you use?

Since the best example of pooled resource to crack hashes is the bitcoin network, currently churning through 2.14 ExaHashes/s. I want to ask, if the resources of this network were pointed towards cracking blowfish, and (by extension) bcrypt, what…
Amin Shah Gilani
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Any way to prove that two devices are in the same physical space, for authentication?

I need to come up with digital proof that two physical devices are in the same (approximate) location whenever that transaction occurs. This could be: A digital ID and the authenticator A consumer and a merchant A digital key for a door, and a…
makerofthings7
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Are the online bitcoin wallets secure?

I have an online bitcoin wallet. I sometimes read news about some online bitcoins wallet websites getting hacked. For sure when this happens, all the bitcoins of all of the users are stolen. Articles like this corroborate this. I guess there is no…
OscarAkaElvis
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Why is DARPA interested in secure messaging platform using blockchain technology?

DARPA (US Defense Advanced Research Projects Agency) has released a Request for Proposal for a Secure Messaging Platform using a blockchain framework. The following is the Objective paragraph from DARPA's call for proposal: OBJECTIVE: Create a…
user2065276
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I have been hacked and im not sure how -- Ubuntu 14 VPS, crypto wallet

I own a crypto currency website and host a wallet on a VPS, for thew past 3 months someone has been removing coins (very little amounts at a time) from the wallet and i have no clue how, here are the details i have: All server run ubuntu 14.0 on a…
beepbaapboom
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How does combining SHA256 with RIPE-MD160 compare to SHA256 + SHA-3?

Bitcoin stores its addresses as a combined SHA256 + RIPE-MD160 hash. Is it correct to assume this is done to prevent a failure in the algorithm? Since SHA3 was designed to be an alternative to SHA256, and uses a completely different methodology,…
makerofthings7
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Why don't sites implement a system where a wrong password causes a 3 second delay?

I am into bitcoin right now, and the password threats scare me a little... Not so much for me, because I use LastPass and generate new passwords at 20 characters and it includes symbols, upper and lower case letters as well as numbers. However, I…
Campy
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Is blockchain security dependent on number of transactions in time?

I have a basic understanding of how blockchain technologies works. I know that in depends on the ledger where are transactions recorded and can be effectivelly verified. No one should be able to modify the ledger because of the cryptographic hash…
user1563721
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How to encrypt with ECDSA?

Suppose there's a transaction in the blockchain in which a given address transfers bitcoins to whoever. I need to encrypt a message so only the owner of that address will read it. I have his public key, but it's a ECDSA key, and as far as I know,…
Nathan Parker
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Is it secure to create a Bitcoin address from a private key generated by Rand() instead of cryptographic elliptic curve

I am writing a C++ application that creates a Bitcoin address. I am having a hard time installing openssl for windows and making it work for visual studio. So, I am asking myself, if I create a private key, let's say a hex string of 64 chars, by…
WereAskingIt
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How to securely derive a second password specific to an user

I'm giving each of my users an unique Blocktrail wallet that is protected by two API keys (which the server knows) and one passphrase (unique to each wallet). I want the wallet's passphrase to be unavailable to anyone but the logged-in user…
Tarman
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which memory hard hashing algorithm can equalize low-computational and high-computational power devices to utilize blockchain in the IoT?

Recently IBM and Microsoft showed their interest (IBM post, Microsoft post) in utilizing bitcoin's blockchain for internet of things (IoT) development. Let's assume that in close future the blockchain technique to be implemented in smart cars…
Nur
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Bitcoin and fraudulent transactions

I was reading Police suspect fraud took most of Mt. Gox's missing bitcoins, and its effectively claiming the missing 650,000 bitcoins vanished: Of the 650,000 bitcoins unaccounted for -- worth about US$208 million today -- only about 7,000 appear…
user29925
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Offline phone security

How secure is an offline android phone? Some background. I want to use an app called Bither on android, which allows me to create a cold wallet on 1 phone and a hot wallet on another phone. Cold wallet is a wallet which is created on a computer…
oshirowanen
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What does "by continuing you agree to share resources" on a website mean?

I recently encountered this message on a website: "By continuing you agree to share resources. Your browsing speed will not be affected." When I get 'learn more', it redirected to me an obscure digital currency webpage (I forgot the name). It was…
WorldGov
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