Questions tagged [encryption]

For questions relating to encryption operations and algorithms as they apply to crypto-currencies specifically.

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43
votes
9answers
9k views

How can I keep my wallet secure?

The standard Bitcoin client does not encrypt wallet files, so any malicious user that gains access to this file will be able to transfer all the coins to their own wallet. Furthermore, if I lose the ...
38
votes
7answers
50k views

How long would it take a large computer to crack a private key?

I am doing a presentation on Bitcoins and I was looking for some calculations to make people feel safe about the private key encryption. Please first answer, how long in bytes the private key is, ...
17
votes
2answers
12k views

Why does the length of a bitcoin key vary?

Why does the length of a bitcoin key vary? Why aren't they all the same length?
15
votes
1answer
7k views

How does bitcoind generate a new address if the wallet is encrypted

Suppose that my wallet is encrypted with a passphase and currently I have not provided bitcoind with the passphrase to access the private keys section of the wallet. If I enter: bitcoind ...
15
votes
3answers
10k views

Are there Bitcoin password crackers I can use to recover forgotten passwords?

I've lost the password to one of my wallets (it's a small one, don't worry). I was sure I remembered the password ... but evidently I don't. Is there a program that I can use to brute-force my ...
12
votes
2answers
300 views

Can I force my wallet to only have news keys, post-encryption?

Now that v0.4 of the bitcoin client has encryption I've gone ahead and encrypted the keys in my wallet. But I had previously made backups of my (unencrypted) wallet and those keys are the same keys ...
11
votes
4answers
19k views

Won't ASIC miners eventually break SHA-256 encryption?

I might be confused as to how Bitcoin works, but as far as I can tell, ASIC miners are getting better every year and faster at cracking SHA-256 encryption. Won't this cause the eventual complete ...
11
votes
1answer
3k views

How to Call JSON-RPC SendToAddress when the Wallet is Encrypted?

I'm using JSON-RPC to send commands to my bitcoind, and it works fine. Now I want to encrypt my wallet. When I've done that, I will need to send the passphrase when calling SendToAddress. How do I do ...
10
votes
1answer
3k views

How does the Electrum wallet encryption work?

Nube bitcoin question... I created an electrum wallet, and can find it under appdata on my windows machine. When creating it I set up a pass phrase and password. I sent a small transaction into one ...
9
votes
3answers
2k views

How would one “Encrypt” a message using a Bitcoin *public key* and use its private key to decrypt it?

I have the following text string: This is a test message. Using my bitcoin public key (bitcoin address?), how can I encrypt this message? How would I decrypt the message using a bitcoin private key?
9
votes
2answers
4k views

If I lost my public keys, could I recover them from the private key? [duplicate]

Possible Duplicate: How are public & private keys in an address created? If I lost my public key, but still have the private key, is it possible to recreate the public keys. How many public ...
9
votes
1answer
770 views

Does the BerkeleyDB-based wallet.dat implementation leak private key data?

I read this little nugget on the bitcoin client bug tracker: the bdb binary log files can also contain sensitive data such as private keys Is that true? Does this mean that even with an encrypted ...
8
votes
2answers
8k views

Backing up my bitcoin wallet - is wallet.dat all I care about?

I know that there are many duplicates of this but I'm hoping that the way in which I word this explains and helps not just me, but others as well. In any of the coin wallet bitcoin and the alt coins,...
7
votes
5answers
2k views

BIP38 or Brain wallet?

I have seen many videos about paper wallets and different ways to store BTC. And I have choose to store using a cold wallet (paper wallet). But I am not sure what option I should choose: a normal ...
7
votes
3answers
2k views

Using the bitcoin wallet PKI for message encryption

Is it possible for a message sender to encrypt a message string with a receiver's public wallet address, email this ciphertext to the receiver and then have the receiver decrypt the message using ...
7
votes
1answer
5k views

How to import a private key to an encrypted wallet (on standard client)

I have a standard client (QT client on OSX) with an encrypted wallet. I've tried to import keys with pywallet, but while it claimed to be importing them, when I ran again the bitcoin client, it said ...
7
votes
1answer
10k views

Forgot wallet encryption password, are any brute force tools available? [duplicate]

I have an idea of what my password should be, but am missing something. Are there any tools or bash scripts to brute force my wallet passwords? If a dictionary is required, I can pre seed it as ...
7
votes
1answer
1k views

How to 'attach' metadata to a bitcoin receive address

I need to generate a receive address that is directly associated with some metadata, M, that forms part of a verifiable contract. I require that customers can verify that an address really was ...
7
votes
1answer
553 views

What OpenCL video cards (or FPGAs) are best for multiplication?

I'm benchmarking some Bitcoin related software and am looking for cards that are better at parallel multiplication vs parallel addition. Is there any prior work that may have this information? ...
6
votes
1answer
1k views

Where and how is secp256k1 used within Bitcoin?

Bitcoin is unique that is uses secp256k1 to secure it's transactions; and any cryptographic attack against this algorithm is probably going to be percieved as an attack against the bitcoin network. ...
6
votes
3answers
685 views

Papers/Books on how bitcoin works from a mathematical perspective?

I'm a math student interested in Cryptography. Is there any paper or book which explains, in mathematics and cryptography terms, how bitcoin (more general, a digital cryptocurrency system) works? In ...
6
votes
1answer
428 views

What happens when an encrypted wallet runs out of keys?

Say someone wanted to be evil to the main client and set its wallet to contain one key, lock it, and then start mining. After the first block was generated, the client would traditionally create a new ...
6
votes
2answers
416 views

Do keypool keys from an unencrypted wallet backup become unusable once I encrypt my wallet?

I'm a little confused by this, which i found in the technical documention: When wallet passphrase enrcyption becomes enabled, any unused keys from the keypool are flushed (marked as used) and new ...
6
votes
3answers
15k views

How do I unlock, decrypt, Bitcoin wallet?

I'm new to Bitcoins and I downloaded the new beta version with the encrypted wallet. I encrypted my wallet but I have no idea on how to decrypt it. It is locked. How can I unlock/decrypt my wallet? ...
5
votes
2answers
4k views

Is this the proper way to use Bouncy Castle to generate a Bitcoin compatible key?

I'd like to use Bouncy Castle to generate the keypair for use with all *coin variants. Is this the correct implementation to get the correct ECC curve that the *coin variants use? Org....
5
votes
1answer
834 views

Is this how I should calculate a Double SHA256

So I have a function called sha256 which will take a string and return the SHA-256 hash. var First = sha256('myfirstSHA'); And the output is the hex: ...
5
votes
1answer
334 views

Does a Vanity Address reduce the randomness / entropy of the private key? Is there cryptographic proof?

Since a vanity address discards many "valid" keys in order to find one that matches a pre-determined string, I think that the "randomness" of the data would be reduced, thus weakening the key. Is ...
5
votes
6answers
1k views

Safely convert paper wallet to encrypted online wallet

I started investing a not insignificant part of my salary into BTC a few years ago. I created 10 paper wallets (using bitcoinpaperwallet.com) on a dedicated laptop disconnected from the Internet. I ...
4
votes
1answer
2k views

How can a deterministic wallet have one private key but multiple public keys

If we take for example bread wallet. There is one mnemonic to remember, which means one private key? But when you use the app, your public address constantly changes. So more than one public key? ...
4
votes
1answer
143 views

Is two-phase encryption planned for the standard client?

Currently, the standard client supports encryption, but only for actions that change its state (send money, generate address). I would like the client to require two passwords - one to view any ...
4
votes
4answers
376 views

How can I test and verify a vanity key before I send coins to it?

I ran vanitygen and oclvanitygen on the same machine, and realized after my run that both exe's share the same output file. I've had experience in the past where many programs append to the same TXT ...
3
votes
3answers
3k views

How do Ledger Backups get stored?

Scenario Say you have configured a ledger wallet with 10 BTC and 10 ETH. You then lose this said wallet but you have the 24 unique words. You buy another ledger wallet enter the 24 words and BAM, ...
3
votes
2answers
860 views

Multibit security with regards to “backup” folders

I'm using the MultiBit client to manage my wallet (right here on my computer), but I am concerned about the security with regards to the *-backup folders that it creates automatically. When I inspect ...
3
votes
1answer
2k views

Bitcoin-Qt - backing up unencrypted wallet then encrypting it

If I back up unencrypted wallet.dat somewhere safe (TrueCrypt volume) and then encrypt the wallet by Settings / Encrypt Wallet, will my backup still be useful? I think the message after encrypting the ...
3
votes
3answers
2k views

Comparing Bip 38 to AES256

Can anyone explain what are the advantages of using BIP 38 Bitcoin wallet encryption to simply encrypting the private key with AES256?
3
votes
2answers
862 views

Does the public key associated with an address become part of the public record after it has been used to spend?

Since bitcoin addresses are hashes of public keys and not public keys as such, if one wanted to craft a message that could be decrypted by the generator of an address, that can't be done just with an ...
3
votes
2answers
1k views

What is the current state of BIP 38 (encrypted paper wallet) integration with cell phone wallets?

Given current implementations, is there a wallet that I can use to scan a private key, then enter in the password as a PIN, and the wallet will send from the key and sweep the rest onto a key ...
3
votes
3answers
5k views

Wallet is encrypted and currently locked, How can get unencrypted (unlocked) it?

Wallet is encrypted and currently locked, How can I unencrypted the wallet to unlock? Because of my Bitcoin wallet not getting synchronising currently, so I could not get bitcoin balance on one of my ...
3
votes
1answer
664 views

How complex can my bitcoin wallet encryption key be?

What are the requirements and limitations of the password that the satoshi bitcoin wallet allows the user to set?
3
votes
2answers
2k views

Do all Cryptocurrencies uses same Public key Cryptography algorithm?

I have been trying to read about how Public key cryptography works and I have just understand what public key cryptography is and how it differs from symmetric key cryptography. I have also just read ...
3
votes
2answers
864 views

Should I put my bitcoin wallet on an encrypted disk or not?

Is it really beneficial to put my bitcoin wallet on an encrypted disk (LUKS encrypted)?
3
votes
1answer
2k views

Do i delete the Bitcoin folder & data directory in Appdata after i copy it on an encrypted drive?

I am trying to complete the instructions described here https://en.bitcoin.it/wiki/Securing_your_wallet#Windows . I have already done the Truecrypt part and installed the Bitcoin client. But i have ...
3
votes
1answer
73 views

Why bitcoind will shutdown after encryptwallet?

As mentioned in the bitcoin-cli document for encryptwallet command, bitcoin daemon will shut down after encrypting a new or unencrypted wallet. My question is about the reason for shutting the node ...
3
votes
2answers
2k views

Is this how to generate a bitcoin address with python?

So I have already the public key. My question is if I'm applying correctly the b58 encoding, since bitcoin uses b58check, and also adds x00 prefix. Can somebody explain me that? Thanks. import ...
3
votes
2answers
7k views

how do I create and encrypt a dogecoin wallet?

I've looked at the dogecoin wiki, but don't see any resources explaining how to actually create a wallet and encrypt it. I'm running dogecoin-qt on Linux. Under "much receive" on the GUI, I can add ...
3
votes
1answer
2k views

What are the drawbacks (if any) of encrypting your wallet with Bitcoin-Qt?

Basically, is there any reason not to encrypt your wallet? The only drawback I can think of is forgetting your passphrase and losing access to all your bitcoins.
3
votes
2answers
935 views

How does an encrypted wallet persist used keys from “getnewaddress” and the keypool after a restart?

I'm reading this wiki on wallet encryption and am confused on how I can call getnewaddress as described here and where that is being tracked after a restart of bitcoind. When a wallet is encrypted,...
3
votes
1answer
478 views

Does Bitcoin wallet encryption also protect my sending and receiving addresses?

Bitcoin wallet encryption makes sure (by encrypting the private keys with a passphrase) that someone who finds your computer or your Dropbox or your backup drive (including wallet.dat) cannot spend ...
3
votes
1answer
543 views

How do we have one-to-one mapping given the key size differences?

If public keys are 34 characters long, and private keys are 61 characters long, then the combinations of 34 characters is not sufficient to give each combination of 61 characters a unique pair. My ...
3
votes
3answers
161 views

Securely encrypting a cold storage wallet

I'm going to buy bitcoin to exchange BRL to CAD currency, as it's gonna be a great amount I'm concerned about the security of my wallet. I don't want to use a physical backup like paper or device ...