Hello,

Three questions concerning invalid transactions, just so I can try to understand some of the technical details of bitcoin a bit better.


1. Do transactions ever time out if not accepted into the block chain?

e.g. if I create a transaction today, and it happens to be invalid, is it possible it will unexpectedly get accepted, e.g. with a later release of the bitcoin block chain code that has policy changes, maybe in x years time? (assuming transaction this would have to be accepted by miner *and* the block chain code)



2. I assume the following is an example of an invalid transaction. At least it has not any confirmations since 2014-04-02. How do I tell why it hasn't been accepted (trying to understand/parse the scripts here, but can't really make sense of them in the way they are presented on the websites I have seen so far).

http://live.insight.is/tx/83cdc4c243b3f106c22f50e0d30ce86a45e61aa2bc03c8f1f1634239e64909d7

According to this page, the scriptSig starts of with a single "0". Aren't they meant to be double digits? Ok, ignoring that for now.

Then, if my understanding it correct, it pushes three items on the stack:
* 0x30 byte signature
* another 0x30 byte signature
* a 0x52 byte  BIP0016 complaint pay-to-script. Except 0x52 is the opcode for "The number in the word name 2 is pushed onto the stack.", not push 0x52 bytes of data. Which I don't understand, and at this point I am not really sure what is going on.

Maybe the website is not printing the push-item-to-stack opcode, just the data that gets pushed, which is what is confusing me???

Then the following script, from the output in the parent transaction abd231512a7d4524c3424add1c466eff250ebe221204a765a5d28118d21b7a7a is executed:

OP_HASH160 2a5edea39971049a540474c6a99edf0aa4074c58 OP_EQUAL

Which checks the hash of the BIP0016 script is correct.

Followed by popping the script of the stack, executing it, and that script checks the signatures are correct.

Is my understanding is correct?

If so, how do I determine why the process appears to be failing, at least for this transaction?



3. Would it be possible to pay for something with a transaction that contains an invalid scriptPubKey, (e.g. the pubKeyHash is invalid - if I understand this correctly would mean this output cannot be used as an input for further transactions), and trick the recipient into accepting this as payment? If not, why not?


Thanks