BTC addresses starting with "3" what are they ? simplified explanation.

[nc50lc]

Thanks for pointing this out, do you happen to have any example of online wallets that provide multi-sig legacy address starting with "3" instead of a addresses starting with "1" or actual segwit addresses starting with "3"?
-snip-

I know one local exchange/payment processor that previously provided multisig "3" deposit addresses and later, SegWit "3" addresses for new accounts: Coins.ph/Coins.pro.
They kept the multisig ones because they are using "fixed deposit address", but the user will never distinguish which is which unless they are a bit knowledgeable in "input scripts".

Example transaction made by Coins: 8d3088ebff1dc5554cd3eb747475190b56a9e4264fb8298e8b192f6c713fad0f
The first input address is a multisig address having this redeem script:

Code:

		"type": "multisig",
		"addresses": [
			"1LRqsYChNsC5GmPtyN5bA8t9nL9UtDaCxZ",
			"1KL1Q3AoU7fcdAVwKt1HPUwDAuBzEqgop9",
			"16WX1TA21fZN2RjWKgDoS9wYe3ubnM498M"
		],
		"p2sh": "3LgUWbSkwvKoTdn8xexf7GqpVBRLwMs6TE"

The next 8 addresses all have "Witness data" indicating that those are P2SH-P2WPKH SegWit addresses.
You can view it on the transaction's link above under "input scripts".

[mikeywith]

The next 8 addresses all have "Witness data" indicating that those are P2SH-P2WPKH SegWit addresses.
You can view it on the transaction's link above under "input scripts".

True, i confirmed it , only this address is multi-sig ( non- segwit)

Code:

3LgUWbSkwvKoTdn8xexf7GqpVBRLwMs6TE

but i can't understand the relationship between using a multi-sig and "fixed deposit address" , I mean every address on an exchange is somehow a multi-sig, as you always need their "permission" to spend the coin,and users don't even have access to their wallets, so what is the actual point of having a multi-sig address on an exchange like coins.ph ? sorry i am a bit slow 

[1miau]

Friendly bump. 

I've used your nice explanation how to "detect" nested SegWit addresses as a reference in my list of useful Bitcoin block explorers, I hope it's ok for you. The table is containing a column which block explorers are offering an opportunity to spot nested SegWit addresses - and which block explorers don't do that.