Tag : howto

Claim US$20 for free from Byteball

Byteball is offering US$20 to anyone who installs the wallet and verifies his identity. The verification process is privately done by Jumio through the Byteball wallet; your information will not be public. Only a hash is published to prove you completed the process.

This process has a cost of US$8 but, because of its referral program, I can cover this for you. Just follow these steps:

  • Enter a name and make sure you enable the option “Single address wallet”

  • Go to “Chat”, select “Bot Store” and find “Real name attestation bot”. Select it and add it

  • Open that chat. If no message is shown, write anything to start, for example “?”. Read the instructions. When asked, enter your own address by touching the  icon

  • When asked if you want to store your information private or public, it’s OK to select private
  • Now, the bot will ask you to pay US$8 for the attestation fee. I can cover this for you if:
    • You’re using your passport to verify, not your ID nor your driving license.
    • You have a bitcointalk.org account
    • Your account is Senior, Hero or Legendary with neutral or green trust; or your account is below Senior with green trust by default
    • You commit to use the US$8 to pay for attestation. Take a screenshot (how?) of the process once you’re done to prove this, even if it fails
    • If you don’t use these US$8 to complete this process, you may get negative trust. If you try and the process fails for any reason, of course you won’t get negative trust. But do PM me the screenshot
  • Copy your own address (touch-and-hodl the address you just sent) and PM it to me: https://bitcointalk.org/index.php?action=pm;sa=send;u=169515

  • I’ll send the required amount to your address. Wait until you receive it and it confirms. Go back to the chat and make the payment. For this, touch the “Payment request” link and confirm on the next screen

  • You will receive a unique link to start the verification process. Touch the link to start the process

  • You will then be asked to take a picture of your passport and a selfie. Make sure both pictures are in focus and fully readable.
    Note the site supports a passport, ID or driving license. However, using a passport is strongly recommended as the process can fail if using an ID or license driving. Most probably this happens because formats of IDs and driving licenses change a lot from country to country, unlike passports.
  • Wait a few minutes and you’ll get your $US20 which you can keep or trade

  • Done!

Categories: Crypto-currencies, Giveaways, Tutorials

How to create a bootstrap.dat file automatically

Syncing a crypto-currency wallet can take several hours or even days.

The process of downloading the whole blockchain is slow because it requires P2P communication and validation of this data.
The result is that the client must download much more than the total size of the blockchain at a speed much lower than the actual Internet connection available.

To solve this it’s possible to use a bootstrap.dat file. The user needs to follow these steps to use it:

  1. Download the file and uncompress it.
  2. Verify signatures or checksums provided by a trusted entity. This is to prevent using a fake file.
  3. Stop the wallet if it’s running.
  4. Move the bootstrap.dat file to the wallet’s data directory. It’s usually at %appdata% on Windows (ex: %appdata%\Bitcoin) or $HOME on Linux (ex: $HOME/.Bitcoin).
  5. Open the wallet.

Quite simple! Now the problem is how to create the bootstrap.dat file and how to keep it updated. If you already have a full node running Bitcoin or any other crypto-currency here I explain how to provide an always-updated bootstrap file, automatically.

How to create a bootstrap.dat file

First, you need to write a script to create the file on your server. This script must follow the following steps:

  • Go to the data directory of the coin whose bootstrap file you want to create
  • Read all the blkXXXX.dat files and concatenate them in a single file
  • Rename the result as bootstrap.dat
  • Calculate the checksum of the file
  • Optionally compress it
  • Move it to a public location when users can download it

Here’s a sample script written in bash.

# Go to the coin’s data directory
# Replace CAPTcoin by Bitcoin or any other currency
cd ~/.CAPTcoin

# Find all the block files with the command “ls -1 blk[0-9]*.dat”
# Use the sort command to make sure they’re in order
# Use xargs to prevent an “Argument list too long” error
ls -1 blk[0-9]*.dat | sort | xargs cat > bootstrap.dat

# Create a file including the current date and the checksum of the file
echo “bootstrap.dat file, created at `date`” > bootstrap-sum.txt
echo “sha256sum: `sha256sum bootstrap.dat | awk ‘{print $1}’`” >> bootstrap-sum.txt
echo “md5sum: `md5sum bootstrap.dat | awk ‘{print $1}’`” >> bootstrap-sum.txt
echo “Verify before using it!” >> bootstrap-sum.txt

# Optionally, compress the file. You need to install zip for this
zip bootstrap.zip bootstrap.dat
# Remove the original file
rm -f bootstrap.dat

# Finally, move the resulting files to a public directory
# It’s recommended to move bootstrap-sum.txt to another server for security
mv bootstrap.zip /var/www/captcoin.com
sftp … bootstrap-sum.txt


You can run this periodically by creating a cronjob. For example, this will execute the script every day at 6am:

crontab -e

Add the following line:

0 6 * * * sh ~/generate-bootstrap.sh



Categories: Crypto-currencies, Tutorials