Noob Questions about SegWit Addresses

[jaysabi]

I've been told I need to upgrade to a SegWit address in order to help the adoption and help cut down on tx fees, but it appears most online wallets don't support it yet. I have found a few places to generate a paper wallet, and have a few questions surrounding this.

• Are https://segwitaddress.org/ and https://coinb.in/#newSegWit reputable places to generate a SegWit address?
• Once I transfer btc from a non-SegWit address to a SegWit address, can a SegWit addresses send transfer back to a legacy address? (Reason being if I needed to sell, my exchange currently doesn't support SegWit, so I assume the only way to sell would be to transfer to a legacy address and then transfer to the exchange?)
• Are SegWit addresses and legacy addresses on the same blockchain, or are they two different chains?
• As online wallets adopt SegWit, I assume if I were to generate an address with either of the above websites (provided they're legit), I would be able to use the private key to sweep the coins into them?
• Is it possible to sweep coins from a SegWit address to a legacy address?

Any help and insight is appreciated.

[OmegaStarScream]

1. SegWitaddress is a new service while Coinb.in exists for a few years now. Both services are open source, so you can always check yourself.
2. Services you mentioned above generate addresses with '3' and not bech32 (start with bc1) like Electrum does, so you shouldn't find compatibility issues.
3. Same chain, It's a soft fork.
4. You have GreenAddress which already support SegWit.
5. Sweeping is basically sending from an address to another so yes, you can do that.

[jaysabi]

1. SegWitaddress is a new service while Coinb.in exists for a few years now. Both services are open source, so you can always check yourself.
2. Services you mentioned above generate addresses with '3' and not bech32 (start with bc1) like Electrum does, so you shouldn't find compatibility issues.
3. Same chain, It's a soft fork.
4. You have GreenAddress which already support SegWit.
5. Sweeping is basically sending from an address to another so yes, you can do that.

Thanks mate. So essentially, there's interoperability between SegWit and legacy addresses, so there should be no issue transferring coins from an one to the other (including sweeping, which is just a method of on-chain transfer), right? If I had coins on a SegWit address and wanted to sell, I could just transfer them to an exchange if it it hadn't implemented SegWit yet?

The thing on opensource is I'm not a coder, so I have no ability to evaluate if the either of the services listed in point 1 are legit or sketchy. I'm really relying on other people with the expertise to know there.

[Xynerise]

Thanks mate. So essentially, there's interoperability between SegWit and legacy addresses, so there should be no issue transferring coins from an one to the other (including sweeping, which is just a method of on-chain transfer), right? If I had coins on a SegWit address and wanted to sell, I could just transfer them to an exchange if it it hadn't implemented SegWit yet?

Exactly, yes.
Segwit is backwards compatible (except Bech32 segwit addresses but that's because it's a new address format) so you can send and receive from Segwit addresses.

The thing on opensource is I'm not a coder, so I have no ability to evaluate if the either of the services listed in point 1 are legit or sketchy. I'm really relying on other people with the expertise to know there.

Use popular ones that are open source then.
That way the more people that use it the better chance it is scrutinized properly by various people with different experience.
Coinb.in is popular, old-ish and open source so it's good, but you'll have to download the website on a live CD on an airgapped PC to use it safely.
Why not use Electrum instead?

[codewench]

Once I transfer btc from a non-SegWit address to a SegWit address, can a SegWit addresses send transfer back to a legacy address?

There's little usefulness to arbitrarily moving your legacy addressed funds. You might as well let them sit until you need to spend them. You'll have to pay a miner's fee either way. If you don't move them, it'll be one legacy level fee (per UTXO). If you do move them, it'll be one legacy fee and one SegWit fee.

About the only reason to move them is to arbitrage transaction fees. You might consolidate several legacy UTXO's into one SeqWit address when fees are low so that you can save money in the future when fees might be high. Or you might convert using a very low fee that takes days to confirm so that you can promptly pay an invoice at a high satoshi/byte rate, but at a lower total cost.