If you have lots of coins in your online bitcoin wallet,will posting that address in public like forums,facebook etc make it more vulnerable to hacking?
1.Should such addresses be kept secret as much as possible to keep them away from hackers eye?
2.If kept secret,is there a way for others to know how many wallet addresses holds big amount if bitcoins?
1. No addresses are relatively secure as of now and there is no way for anyone to guess the private key unless the RNG used is weak. If the RNG is weak, the address would probably be emptied by then. The only compromise here is the privacy since it ties the address to a specific person.
2. Blockchain is public so users would be able to see the balance in the address. You can, however, spread it out over various address while taking note not to spend-link to send directly to the different addresses.
If you have lots of coins in your online bitcoin wallet,will posting that address in public like forums,facebook etc make it more vulnerable to hacking?
1.Should such addresses be kept secret as much as possible to keep them away from hackers eye?
2.If kept secret,is there a way for others to know how many wallet addresses holds big amount if bitcoins?
If you have lots of coins in your online bitcoin wallet,will posting that address in public like forums,facebook etc make it more vulnerable to hacking?: Yes, just as posting pictures of a stack of gold or a box of diamonds will increase your odds of getting robbed. You are essentially making yourself a target. Someone could want to hack you now who previously wouldn't have known.
1.It depends on your privacy and storage techniques but usually YES
2.They will still be on the blockchain so technically yes.
Nice, okay. Could you please explain how posting a public key would increase its vulnerability? - have you got an unknown method of spawning a private key from a public key?
Why bother...
No it want increase its risk of getting stolen. You need to worry more about the trust between you and your wallet provider. No online wallet is hack proof, but levels of mitigating attacks do vary depending on your provider. Right now, blockchain.info is the only 99% provider that I've seen. They if I remember correctly, they give you the KEKey (key encryption key)
If you're using P2PKH addresses, you're fine if you don't reuse address. If you use P2PK hash, you might be vulnerable to quantum attacks even if you did not spend the coins from the address before. However, this isn't a valid concern since quantum technology is quite sometime away before it can crack public keys.