How can I recover dogecoins sent to a Bitcoin address?

I had transferred my Poloniex dogecoin cryptocurrency and accidentally sent it to a Bitcoin paperwallet using walletgenerator.net. It did go somewhere but do not know where.
Is there someone to contact for missing cryptos? I thought the Dogecoin address is different than the bitcoin and would not transfer.

To run bitcoin core testnet on Ubuntu 16.04

How can I run Bitcoin core testnet version on ubuntu 16.04 platform ? I am getting so many reference about how to run bitcoin core mainnet but it will take around 20 days to synchronize with the network as per my bandwidth and also will take my half of the HDD. So I opt for Testnet. Can someone explain me how to insatll bitcoin core testnet on Ubuntu 16.04? I would be grateful. Step by step explanation or reference would be much appreciated.

Encrypted message with nLockTime

I know you can delay a transaction’s accepted date by using nLockTime. I’m still looking for the simplest way to generate a transaction with nLockTime, but that’s another topic.

I’m wondering if there’s a way to use this feature to send a message that will only decrypt after the time is due.

I know that a transaction broadcast with nLockTime already has all details visible and the amount is simply not yet spendable by the recipient. Is there a way to also make the note on that transaction encrypted until such date? Can I use bitmessage to achieve this somehow? How about another coin such as Dash or zCash which I assume also encrypt the transaction’s note to anyone except the recipient [do they actually do this, especially Dash]?

The idea is to send a message that only the recipient can decrypt and only after a certain date, with no manual intervention in the future, nor anything else involved. It would be ideal if they received that message in their wallet like any transaction after it’s due, but the message shouldn’t be viewable by others nor by the recipient in advance searching, say, in a block explorer.

Thank you

After Segwit Activation, what is the largest block size possible?

The code says MAX_BLOCK_SERIALIZED_SIZE = 4000000, but that is actually not a actually consensus rule as stated here:

https://github.com/bitcoin/bitcoin/issues/10289

The actual consensus rule is based on MAX_BLOCK_WEIGHT, which is also 4000000. It’s unclear to me what the minimum weight a p2wpk or p2wsh transaction can have. Specifically, what’s the best witness-serialized size/weight ratio that a transaction can have post-segwit activation?

That should answer the question of what is the largest block size possible post-segwit activation.

Does signing a message weaken the address’ security?

Will signing a message (without doing any $ transaction) reveal the private key to the blockchain just the same/similar way the private key is revealed to the blockchain when you do a $ transaction?

The point is, doing a transaction weakens the security of the address a tiny bit because the private key is revealed to the blockchain. That’s one reason why change/new address is used with every transaction.

But what about just signing a message? Will that weakens the security of the address a tiny bit too?

What is the weight of a block that contains no pay-to-witness scripts?

I’m trying to understand block weight, a metric introduced by segwit (BIP-141):

block weight = 3 * base size + total size

“base size” is the length of a pre-segwit block, which contains only serialized base transactions. “total size” is the length of a post-segwit block, which contains both serialized base transactions and serialized witness transactions (as defined in BIP-144). The weight of any block must not exceed 4 MB.

The weight of a block without pay-to-witness scripts can found by computing total size. It’s tempting to set base size equal to total size:

block weight = 3 * base size + base size = 4 * base size

But this assumes the length of the serialization of a non-segwit base transaction equals the length of the serialization of a non-segwit witness transaction. This doesn’t appear to be the case:

Serialization

The witness transaction serialization format appears to follow the structure shown above (which is also the input to find wtxid). Notice two additional bytes before the list of inputs (marker and flag, respectively). Moreover, the witness requires at least one byte (the witness field count) even if no fields are present.

In other words, a witness transaction serialization will always be at least three bytes longer than a base transaction serialization, regardless of whether a witness is present.

If this is correct, then segwit is in fact reducing the block size limit for blocks devoid of pay-to-witness scripts by a factor proportional to the number of transactions in the block.

What am I missing?

Bitpay Without Credit Card

I am having trouble finding this information so I would like to ask those who use BitPay:

  1. Can you create a BitPay account and spend coins without having a Credit/Debit Card associated with your account?
  2. Tying into the first question can you use Bitpay without tying any personal information to your Bitpay account?

Some stores only accept bitcoin via Bitpay but I don’t want to create a Bitpay account if it removes my anonymity.

IOUs – Cold wallet relationship (Poloniex, Kraken, Gatehub)

(I’m new to cryptocurrencies.)

Please answer the following questions seperately for Poloniex and Kraken if they behave differently.

1) Can I buy example given XRP on Poloniex or Kraken and send it from there to my cold wallet?

2) Are these XRP on Poloniex or Kraten IOUs?

3) If they are IOUs and I send the XRPs to my cold wallet, does it effect my money on my cold wallet if Poloniex or Kraken goes broke (do I loose my money in that scenario)?

4) Is there any difference between sending my XRPs from Kraken/Poloniex to my coldwallet and sending my XRPs from Gatehub to my coldwallet?