--[[ Copyright (c) 2019, Vsevolod Stakhov Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ]]-- -- Bitcoin filter rules local fun = require "fun" local off = 0 local base58_dec = fun.tomap(fun.map( function(c) off = off + 1 return c,(off - 1) end, "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")) rspamd_config:register_symbol{ name = 'BITCOIN_ADDR', callback = function(task) local rspamd_re = require "rspamd_regexp" local hash = require "rspamd_cryptobox_hash" local wallet_re = rspamd_re.create_cached('^[13][1-9A-Za-z]{25,34}$') local words_matched = {} local valid_wallets = {} for _,part in ipairs(task:get_text_parts() or {}) do local pw = part:filter_words(wallet_re, 'raw', 3) if pw and #pw > 0 then for _,w in ipairs(pw) do words_matched[#words_matched + 1] = w end end end for _,word in ipairs(words_matched) do local bytes = {} for i=1,25 do bytes[i] = 0 end -- Base58 decode loop fun.each(function(ch) local acc = base58_dec[ch] or 0 for i=25,1,-1 do acc = acc + (58 * bytes[i]); bytes[i] = acc % 256 acc = math.floor(acc / 256); end end, word) -- Now create a validation tag local sha256 = hash.create_specific('sha256') for i=1,21 do sha256:update(string.char(bytes[i])) end sha256 = hash.create_specific('sha256', sha256:bin()):bin() -- Compare tags local valid = true for i=1,4 do if string.sub(sha256, i, i) ~= string.char(bytes[21 + i]) then valid = false end end if valid then valid_wallets[#valid_wallets + 1] = word end end if #valid_wallets > 0 then return true,1.0,valid_wallets end end, score = 0.0, group = 'scams' }