Bitcoin Forum

An Israeli Firm Claims that they have recently developed an undo button for all Bitcoins transactions. Apparently their main goal was to tackle problems related to human errors , but then again what am scared about is , how people will use it , it can very easily be used for scamming people .


https://cointelegraph.com/news/israeli-blockchain-startup-offers-undo-button-for-bitcoin-transactions (https://cointelegraph.com/news/israeli-blockchain-startup-offers-undo-button-for-bitcoin-transactions)

Apparently 18% people reported loss of Funds due to human errors , thus this might serve great for them . Retrievable Transfer , as they are calling it would give the sender the power to retrieve the amount until the right code is provided by the receiver. My take on this : they are somehow using a password which needs to be provided by the receiving party and this might be super helpful in places which involves transactions of very high Amounts .

The person Aims at making these transactions as safe and secure as online banking source claims , but they are already more secure , they are just gonna add one more feature now .

It's going to be free till a transaction of 1000$  , so before you strike a deal , be careful :3 Ask about everything someone might use it in not so good way .

Amazing innovation by the way , lets see if it works ..

Most wallets have this feature, It's inform of a password or fingerprint authentication from the sender's wallet software. All the major wallets i have used be it electrum, Jaxx, Trust Wallet all ask for password or confirmation shortly before sending funds. This is the time someone can avoid sending money to a different address by mistake.

So, after poking around on their support pages for a bit (https://kirobo.io/support/), it seems that it works like this:

I first sign and broadcast a transaction sending coins from an address to I own to another address I own, called the "safe address".
I then sign a second transaction sending the coins from the "safe address" to the recipient.
This second transaction is encrypted with a password I choose, and Kirobo store the encrypted transaction on their servers.
I send the password to the recipient, who logs on to Kirobo's site and enters the password, which then decrypts and broadcasts the signed transaction.
At any point before that happens, I can reclaim my coins from the "safe address", rendering the encrypted transaction invalid.

All-in-all, it seems like a massively over-engineered solution for the problem of not double checking the address you enter. Why would I go through all this effort when I could instead just spend 10 seconds to make sure the address is correct? Not to mention that your transaction is now entirely dependent on a third party.

Was actually trying to say the same stuff on why the hell i would go to all of those process if you can just simply check the address carefully before sending out and
most wallets now do have that verification like input password or some sort before you do able to send such fund on other wallets. Getting rid of human error
is somewhat impossible no matter how you do made up some changes and also this one isnt really that relevant nor needed at all. Its too hassle on my part
or pretty sure in most people too.

Sending coins to your own address is really redundant, especially at the times of high fees, why not just mark existing outspent outputs on a wallet level as "safe outputs" and use them for this feature. It's also possible to cut the middleman and make some software that takes payment request, creates signed transaction and then the user sends unbroadcasted transaction to the merchant, who validates it again and broadcasts if it's all good.

But even now you can just a use bitcoin: urls to avoid copypasting addresses if that is the problem.

And I think most of the time people do transactions by mistake if they do something like taking addresses from their transaction history instead of going to the service and copying the address provided there, so in such scenario there's still a room fore error even with the setup of this startup.

Very complicated.
Much easier solution would be to have some easy way to double check and confirm address of recipient before sending.
One way would also be to save this address in wallet addressbook before sending it.

I assume they did this so you don't have to lock up entire UTXOs. If I have an output of 1 BTC, and I use this method to sign and encrypt a transaction to you for 0.02 BTC, for example, then the other 0.98 BTC can't be spent until you claim your 0.02 or else it renders the original transaction invalid. It also gives a clear way to "cancel" a transaction, by sending the coins from the "safe address" back to the original address. I do agree the whole set up is needlessly complicated, though.

Any good wallet which lets you sign a transaction and then save it rather than immediately broadcasting it could do this.

There's also room for this to be abused. If you send me a password, I can claim the password didn't work and you must have made a typo. So you make a second transaction and send me the password, and then I claim both transactions at once if you have forgotten to cancel your first one.

Double checking an address would literally take a couple of seconds to do and depending on the device you're on, you can open two tabs and compare both addresses directly, rather than having to check the first and last characters.
Using Bitcoin comes with responsibility as the individual decide to be their own bank.

A third party service to facilitate transactions would come with challenges as the system is no longer trustless and you have to depend on them in addition to the bitcoin network.

I am talking about newbies that don't know anything about crypto addresses.
Wallet address book is not third party.
Just let someone send you his address, then you save it in your wallet address book, and then send coins from there.
Much lower % of mistake that way.

This should be the sure way to handle thus and not using complicated logic. The processes involved in this findings from Israel are much that we can't comprehend easily. I. An also see the issue of security with the way they handle the undo button transactions. Personally, anytime I want to execute transactions from my wallet, I always ensure before broadcasting I do double check before finally releasing the transaction to the recipients wallet. This is as simple as A & B, so why the hard way.

The problem with the undo button on the transactions is that lot of people could use it to scam other users. Let's say you buy an iPad and you pay with bitcoin, if there was a undo button you can push it after buying the ipad. and end with the ipad and the money back.

And the main problem with the chargeback is the abuse while buying money. What happen if you buy 5 ETH and then change back the bitcoins. You would easy double your money.

To implement a feature like this you need someone to validate what transactions are real and what transactions are fake, and that is impossible to implement on a decentralized project.

It shouldn't work like that. Even there is an undo button, it is better to process manually, not automatically. Automatic transaction cancellation will lead a manipulation on buying or end with scamming the seller. Also, there should be terms and conditions to be allowed for cancellation or undo. There should be a time limit, so people cannot undo anytime. In this way, there is no one scamming others like the example you stated above.

What's with the deal on this undo button when you can go look straight and spend a few seconds looking at the address where you wanna send it? Electrum itself has this kind of putting your password first before sending so it will make you think twice if you are sending the amount to the correct address. Who's idiot that's gonna send straight their money without looking where it should go? I think this is beyond human error if that's going to happen, I mean could be drunk or something? :-\

After reading op, your question is the best reply for this ambiguis feature.
Did the creator of this feature think about the scam possibilities that can happen because of this?
Irreversible transactions are one of the greatest options in the bitcoin protocole, so anybody thinking to cross over it, is a potential scammer.

Even i was wondering what they are talking about, may be these are solutions for lazy ass people or old people and people with disability or people who are careless but majority of the users just need to verify and double verify before sending the transaction and if you are really lazy in copy pasting then most or all of the bitcoin wallets has QR code function and you do not need a third party to hold our funds.

Undo button is mostly likely not possible because the transaction is already recorded in the Blockchain ledger that is irreversible unless you have very huge mining power, but that could be considered as 51% attack.
I dont know how they done it but most probably the "Undo Button" is not going to work and fake.

Doubling checking (twice or thrice) is somewhat important rather than to have an undo button. Besides, almost all wallets have final confirmation before it sends to the other address in which this time we can think and see if there is a mistake on the address we are about to send.
Unless that undo button will help you back your money even though it was sent already to the wrong address. ;)

This is essentially not an undo button as the funds have not been sent yet, although I think an additional layer or two of confirmation would highly lessen a lot of human errors which are mostly failure to double-check addresses.

Just the same, Kirobo's novel feature could address erroneous transactions which arise from using an old address which turned out to be not anymore accessible by the recipient.  

there are a couple of serious problems here:
1. it introduces centralization where there were none since the user and the receiver both will depend on a centralized company.
2. that centralization is also the enemy of privacy of both the user and the receiver since they now have to log into a centralized shady company to send/receive bitcoin which will definitely record their IP and digital fingerprint alongside their transactions and all addresses.
3. last and the most important is that it doesn't even solve the problem it set out to solve (human error). the user can still send coins from the "safe address" to a wrong but similar looking address and receiver can also still make the mistake of thinking that similar looking address is his.

---

a much simpler but a lot better solution would be a wallet that has some sort of secure channel for communication between the two parties. for example it could use PGP where the user adds the pubkey of the receiver (utilizing Web of Trust) and then receiver sends his address in a PGP signed message which his wallet checks its authenticity before letting user make any payments to it.
this could also happen offline, for example the raw transaction to be signed could have the PGP signature instead of an empty scriptsig which the offline wallet uses to verify the receiving address then signs the transaction.

in this design no centralized shady service is needed and everything happens 100% peer to peer and is a lot safer.

Am I missing something or is this basically a quite crappy replacement of the "Replace-By-Fee" function some wallets like Electrum have, but non-trustless and if RBF had a timer for you to cancel the tx at any point? I guess RBF could be implemented in such a way to be used as a "tx cancelling" function with a very simple 2-step process and, in the end, you do not even need any third party account to do so.

I would rather do it manually than just pressing the "Undo" button. It only takes a short while to manually verify everything.

What I am doing is that on my desktop and mobile device when sending Bitcoin, I usually spend time looking at the first and last letters/numbers to see if they are a match or not.

I always double or triple check before sending Bitcoin, Ethereum or any other tokens.

Not everyone is like you, mistakes will surely be made. I get that the OP worries that there might be things that will go south when this feature becomes prevalent, I have seen this kind of features in games that lets you scam people scot free of their wrongdoing, this feature is a double edged sword and that worries me the most because if there are people who makes mistake then there is surely people who will have a malicious intent.

If that will going to happen, it would be great for all of us who are always having online transaction, there are many people who lost their money because if you had already sent the money then you can't do something to return it to you anymore, there are man victims of that having wrong BTC wallet to send and it will be transferred to other wallet, this thing will be less if there would be undo button on it, but I am wondering if this is really possible, I think it's hard for them to develop this kind of feature especially if the transaction happens so fast.
Indeed, I also doubt that having an undo button would be possible to have on some online transactions, great suggestion to have double-checking of recipients' wallet addresses.

Well I'm sorry but someone who doesn't check the BTC address before broadcasting a tx probably doesn't check the destination IBAN either when transferring money. It's literally the only thing you have to check: address, amount and fees.

If I got it right from o_e_l_e_o's reply from the 1st page, there shouldn't be much of a "malicious intent" to worry about. It's not like you could cancel the tx after it gets broadcasted. Replace-by-fee probably has a higher chance of malicious usage right now than this new feature does.

since the second transaction (going out from the "safe address" to the receiver's address) is never broadcast to the bitcoin network until the receiver claims it from their centralized server, i'd say there is no similarity. no transaction is being replaced or double spent or even undone here. there is a transaction that may or may not be broadcast depending on receiver's decision...

... which makes me think of another vulnerability in this design: the receiver sees the wrong transaction's destination but still confirms it to be broadcast and spent essentially making user lose money and since they never received the coins they have no obligation to end up their end of the bargain.

Thanks for explaining!  That sounds like some sort of custody/third party/intermediary solution. Maybe good for newbies that aren´t used to double and triple check the addresses. As for a advanced trader it sounds like a redundant service. Big players can go to one of the custody services already in existance to do so, like that https://www.cryptoglobe.com/latest/2020/02/bitgo-starts-letting-institutions-trade-crypto-directly-in-cold-storage/

Why not just check the entire address? It only takes a few seconds longer and means you are 100% safe.

This is a good point, actually. In addition trusting someone else to encrypt, store, decrypt, and broadcast your transaction, you are also trusting someone else - the recipient - to check your transaction for you. You are essentially saying "I'm too lazy to spend 10 seconds to read an address - you do it for me and claim the coins if it's right. If it's wrong, please don't screw me over and let me know so I can get my money back." How irresponsible.

I would argue the exact opposite - this is a terrible solution for newbies. It is needlessly complicated, and it teaches them to be lax with their own security practices and trust someone else to do it for them.

Yeah I can do that when using the desktop. It's just my own technique though when using mobile for transferring BTC or other assets, and I didn't have any problem at all since the beginning. What I mean for the first and last letters/numbers (which I forgot to mention earlier) are the first and last five figures of the receiving address when transferring using mobile phone. Everyone has their own method of double or triple checking. Like depositing Bitcoin in an exchange for example, I opened two tabs.

One is from my wallet and the other tab is from the exchange. I do a 'Ctrl+F" thingy on the desktop (but not possible with mobile unless there's an app or feature for that) on my Bitcoin wallet's tab. When I copy the address from the exchange and paste it on my wallet, I do "Ctrl+F" on that and paste the same receiving address if it matches or not to ensure that I would not end up sending it to the wrong address.

Thanks for digging it up, was wondering how the actual implementation worked but it does seem like a simple step/layer anyone could manually do anyway, and not dissimilar to having a forced escrower (like a lot of rich people do when they appoint someone with power of attorney to double confirm their transactions).

So yeah, I don't know why anyone who uses Bitcoin normally would want that, OR why a receive would want to go through that and pay the extra fees and triple the waiting time.

P.S. Really 18% of people make this kind of mistake? I've not once in many years sent the wrong transaction. I have ONCE sent an amount too small but that was a keyboard/browser malfunction that happened only because I was testing dust, a carelessness that would never have happened with a proper transaction.

Oh, now I get it. This now sounds kinda similar for me to the way BEAM's Desktop Wallet (https://documentation.beam.mw/en/latest/rtd_pages/user_desktop_wallet_guide.html#id1) works (not sure if the coin itself has this option or just the wallet), besides the fact that with Kirobo the receiver both initiates the tx and decides whether it's the right address or not:


Well, honestly all these steps could be skipped with a simple "is this the right address?" question. I feel way safer to know that I am the one initiating the tx than knowing the other party is. Now I see the flaws too: you could send a tx with the wrong address and the receiver confirms it, acts as if now the money poofed and all this time the "wrong address" was actually another of his. Guess there's no perfect solution to all the problems - there'll always be a flaw within the blockchain system and trying to "fix" them with centralized stuff has absolutely zero benefits imo.

Makes more complicated when a sender is unsure about the address he can just Copy, Control F, and Control V to find out if the address matches. But whatever it still serves the purpose. I hope it won't prompt confirmation message if BTCs are yet not sent and then the sender can undo it because it can be used to fake and scam.

That's a dangerous way to check. If you are a victim of clipboard malware, which is the main reason to check an address you have copy and pasted is correct, then by copy and pasting an address in to your browser's search function the malware could again change the address to fool you in to thinking it is correct. Once you have pasted the address in to your bitcoin wallet, you should manually check the characters match the receiving address you want to send to without using any software or program to do it for you.

People are lazy and don't bother to check at all, or think that they are checking in a secure manner when they aren't. See the post directly above this one for yet another example of this. Using the copy and paste function to check achieves nothing if it is the copy and paste function which is compromised. Checking the first couple of characters and last couple of characters can also be potentially overcome by an attacker with a database of similar addresses to choose from. Check the entire address manually. It takes 10 seconds to do. There is no excuse for not doing.

2FA is okay for me.
It's already a confirmation if you are sure with what you are dealing with or how much it is.
In old machines, it's like the prompt of "Are you sure?". Yes or No.

Instead of becoming a good service, it could lead to a bad one.
Paypal is already an example of it.
Might as well double or triple check every transaction which also tells every satoshi is important to you.

They have just level up the ignorance of people not checking the address of their recipient. I don't really think it could help people to avoid sending to a wrong address, instead some scammer would just use it to scam more people, just a tool for scams omg. I know many wallets now are requiring the user to enter his/her password, keys or pins to authenticate and approve the transaction that is about to made. We need something to highlight the exact text to see if the address is correct. just like the  CTRL+F of google tools.

Still, that stat's got to be hugely unqualified. 1 in 5 people are too lazy to check, I believe. But 1 in 5 people too lazy AND have their devices compromised like that? If that's true, then people shouldn't even really be trying to learn to use Bitcoin until they learn to identify if they've been compromised. Like kids shouldn't be going around rolling in the hay until they learn to use protection.

But you're right. 10 seconds in time saves heartbreak.

The news at https://cointelegraph.com/ says:
But for me I don't quite trust the third-party service, this may change at any time, I will not feel safe while my coins are in the hands of a third party, so for me I think it is best to do a good address check before sending and this does not take much time.
If this feature could be made available in the Bitcoin wallet itself without the need for a third party then that would be really great.

I saw some a few wallets provide users the feature to undo the transactions. but, usually you can only do such thing if your transaction is not confirmed. Also, if your wallet doesn't have the feature, I guess you can transfer the same amount of bitcoins to your own wallet. But, again this will work if the transaction is not confirmed.

Actually the undo button feature is not needed in my opinion, consider the exchanges and wallets that we use today. Usually after we enter
the recipient's address and the number of coins to be sent, we are asked to reconfirm by entering password or code sent to mobile phones
or email. After that the sending button is active, process all of that in an inaccurate manner directly prevent human errors and to ensure the
security that we are doing the transaction. With these features already more than enough, and does not require an undo button. After all,
as said in the opening post, the undo button feature has risks abuse occurred. So I don't recommend using it.

It does not sound like a development of bitcoin. It seems like a service which they provide for bitcoin transactions to be more safe through encrypting and decrypring or something like that. It is never an undor button for bitcoin transaction. If you use bitcoin on a decentralized wallet, this will never happen.

It looks like they finally found a great solution and thus removed several of the drawbacks of bitcoin blockchain such as immutability, decentralization, disintermediation. You are now less responsible for your own money and rely on centralized parties to keep your bitcoin safe like we used to. This solution is rendering bitcoin less weird looking thing for those who don't want any responsibility, because we definitely haven't yet deserved a right to become financially free if we are still looking for solutions like this.

Seriously, we don't need such solutions that require us to operate in a centralized way while using a decentralized protocol. If you are looking for solutions to prevent human errors, consider decentralized solutions like PayNym reusable codes, for instance.

I always do this thing whenever I'm about to send some BTC to another address. I think every BTC holders have developed this idea of double-checking before sending BTC. No need for the undo button, instead, we must not forget this very important step. If you ask me, I've been doing it for the last 5 years of my journey in the crypto industry, and never in my life I have sent BTC in the wrong address.

Yes you are entirely correct. Even I was thinking of the same thing when I came to know of such a thing.
The first and foremost part is that it involves a third party vendor to initiate a transaction.
Why would we compromise our bitcoins with a third party just so that we don't have to double check the address we are sending our bitcoins to.

I think it's just lame and also it hinders the motive of bitcoin to be used as peer to peer payment method.
Any point where we have to use a third party destroys the motive of bitcoin.

I'll say it's a great solution for those who can't spend few seconds to confirm that the details of their transactions is correct instead of going through the stress of signing transaction here and there. I would say I see no decentralization from this method. Instead of that, why not use a centralized wallet that sends sends confirmation email with transaction details before broadcasting the TX. Much better that way. We don't need and undo button because this is not a bank.

I think the undo button is only for people who are too lazy to double check the address before sending coins. Because in my opinion
no one is lazy to do that which takes only a few seconds, which exists because of carelessness. So things like that will always be
pros and cons. But in my opinion the undo button feature is not needed, try more carefully before sending coins. If it reaches the
undo button realization by involving third parties for bitcoin transactions, there will definitely be a risk.

Laziness or being confident that can't even spend at least 10 seconds to check if the destination address is correct. There is no need to have this undo button but only we need is to change the way we process the transaction. Spending for a few seconds is not the hardest thing to do it and that is certainly a thing to develop rather than having this undo button. If we are irresponsible enough into our money then have to expect the same scenario happens again. I'm not sure how many had experienced (sending to the wrong address) such thing but it seems impossible to have 10 out from 100 tx, maybe it just only 1tx.

Nice Scrow service, they hold the sender coins and decide if let it go to the receiver or if chargeback the transaction...

Am i the only one who can predict a hell tone of scams done with this service. You could buy paypal money and chage back the bitcoin for easy double up.

It does have Pro's but this one wont really be that different on to those service that we have known like Paypal which do have chargebacks or some sort and mostly
this kind of feature is more having a Cons when it comes to making transactions.This is why lots of people do support crypto due to irreversible transaction once
you have sent it to other user and now some service do try out to have that undo button when it comes to tx? no it wont really be that appealing.

Undo button for transactions. what if the sender made payment for a high fee and pick up by miner almost immediately or would there be e central control where the transaction will be help before processing? That will go against decentralization of course. The only best way in my own opinion is to establish a medium of check where the amount and address are confirmed second time before the processing actually takes place. Most wallets have this feature

Exactly, I think for more experience users, we have learn to double or triple check everything, like the sender/receiver address and then wallets have built in passwords before you can send your transactions. Love the idea, but I'm totally against it though, it will make bitcoin centralised to me.

Let's just educate ourselves first, and I think this is the best weapon to not commit this kind of mistakes.

Are you scared that it would be used for scamming people? Mate, no matter how you put it, there will always be people that are using it wrongly. It's just up to you, when you know how people are misusing it, then you have to be careful. Cryptocurrency doesn't have Central control and no unit to report to when you're having problems. Even now that there is no undo button for transactions, a lot of people are still being scammed because they sent their money to a scammer or they sent to a wrong address.

Though the one of sending to the wrong address is a dumb mistake, I have never made that kind of mistake, before I make transaction I request for the address I'm sending to and then I copy it and paste and when I'm about to enter my pin I check the address to be sure of it. I don't really understand why people are making such mistakes.

Sending to wrong address doesn't means you got scammed, it's stupidity. That's why it's better to request for both qr code and wallet address of sender when sending a transaction. All you need is two devices, a PC and a mobile phone that you're going to send the coin from.

Anyone can recover lost coins by creating Hardfork, but will the entire network be forced to follow, no.
You can take back all your currencies or even create a new transaction with thousands of currencies.
The value of these currencies will be zero because no one will want them.
If this happens to Bitcoin, its value will be zero.

This type of invention is expected when cryptocurrency is getting bigger, i read the article and it stated the platform in already available on ledger wallet.
Is this project centralized or we just misunderstand them because they claimed not to hold user private keys?

Not in a situation of someone whose computer was attacked by copy clipboard hijack.

Thats still a better option but most of us dont usually request for the qr code.

I don't understand what you're to say here but the hard fork has nothing to do with recovering of lost coins and aside from the platform discuss on this thread the other option to recover lost coins is through double spending when the transaction is yet to be confirmed.

Most of the online wallet nowadays requires a confirmation before proceeding on the transaction. Not only in the bitcoin wallet but some local wallets have also a confirmation feature to avoid mistake transactions. Undo feature might be helpful but it'll lessen the discipline of checking the correct information on every transactions.
That's why we shouldn't rush things and do the transactions carefully to avoid problems. There are many of scammers in the digital world, always hesitate to transact with someone we doesn't know personally.

Truly quite a nice innovation toward ending human error in making irreversible bitcoin transactions but i think most errors do stems out as a result of people being too lazy to cross check transactions before broadcasting it on tge network. I read about how it works but damn, it's quite a process as you have to make a transafer to some some sort of wallet called safe address prior to sending it to desired recipient with a preset password that which you'll give tge recipient to enable them claim the asset

Would it promote potential scammers? This is great for those honest mistakes incurred by users but I hope scammers will not use this for their illegal activities. As a crypto user, just make sure that your transaction is safe and secure. Don't trust people that you just met over the internet.

We need to monitor the sites carefully before transacting You are right to say that it is not right to believe the people you see on the internet they are more scammers so OPs are most effective in maintaining their security for transactions. OPs are able to give us the right advice A lot of the time scam sites come out through this.

All I know is that it requires confirmation when transacting from a good wallet. In this case a code goes to your phone number or a link goes to your email for the successful completion of your transaction. You should make sure that everything is OK before confirming it. Then there will be no chance of being wrong.

Meh, why not just implement a system wherein the wallet prompts the user to reenter a password and displaying the information on a dialogue box before broadcasting the transaction? Oh, I get it, it's already implemented, therefore this feature isn't really a necessity at all.

I don't get why people using bitcoin need to have this feature. One, knowing that users are using bitcoin makes me think that they at least know that they should be careful when it comes to sending tx as there isn't a chargeback/undo feature in this and; two, given that moat addresses are strings of characters that aren't easily identifiable, users inspect the addresses first.

It's a good effort to tackle the problem of forgetfulness for some people though I don't think that it really is that important IMO.

Worried about the miner to confirm that transaction too, I'm not fully aware of this undo button maybe there is a function where the undo button is only available for a short time, I don't want to think the obvious way of putting an undo button it is really useless and hassle at the same it. What we need is a sense of self-security, the essence of double checking everything upon sending any funds to others.

Or just a visible clipboard software? I haven't see any one using or recommending this, or maybe this isn't existing yet? it would be a lot of save effort.

I read how it works and i must say it's a cumbersome process that is not really neccessary but then again, I've seen lots of people complain about they mistakenly transfer fund to a wrong address or they transferred not the disired amount which is all due to not doing a proper cross checking before broadcasting the transaction

Just read abit about how it works. It doesn't really reverse people transactions(all Bitcoin transactions) on Blockchain like some made it to sound. Their system just help coin senders reverse only their transaction when receivers type codes/password meant for them wrongly(probably typing the codes wrongly multiple times will cause the reversal).
Well, it's an interesting solution to irreversible transaction "problem" in Crypto... only that it relies on third-party & centralization to achieve this.

I guess the fees for complete transaction will increase abit for the sender. And I wonder if the sender will always have to send the codes to the real recipient before transaction is possible... that will probably be better for significant/large transactions.     The receivers always needing to get the codes first before receiving funds could complicate things abit for them unless the process is fully automated and quick