There is a validator on github to check if a bitcoin address is valid or not. (Link: https://gist.github.com/alexandrz/4491729)
require 'digest'
class BitcoinAddressValidator < ActiveModel::EachValidator
def validate(record, field, value)
unless valid_bitcoin_address?(value)
record.errors[field] << "Bitcoin address is invalid"
end
end
private
B58Chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
B58Base = B58Chars.length
def self.valid_bitcoin_address?(address)
(address =~ /^[a-zA-Z1-9]{33,35}$/) and version(address)
end
def self.version(address)
decoded = b58_decode(address, 25)
version = decoded[0, 1]
checksum = decoded[-4, decoded.length]
vh160 = decoded[0, decoded.length - 4]
hashed = (Digest::SHA2.new << (Digest::SHA2.new << vh160).digest).digest
hashed[0, 4] == checksum ? version[0] : nil
end
def self.b58_decode(value, length)
long_value = 0
index = 0
result = ""
value.reverse.each_char do |c|
long_value += B58Chars.index(c) * (B58Base ** index)
index += 1
end
while long_value >= 256 do
div, mod = long_value.divmod 256
result = mod.chr + result
long_value = div
end
result = long_value.chr + result
if result.length < length
result = 0.chr * (length - result.length) + result
end
result
end
end
