Suppose I have a public key for a particular user (perhaps extracted when using the [new public key recovery format][1] included in P2SH, and BIP32 transactions).

* Is it OK *the same key* for both signing and encryption?

Since I'm obtaining the public key from a message, PS2H script, or BIP32 wallet I want to make sure that all secrets (Bitcoins, private keys, and privacy relating to BIP32) are maintained and no risk to privacy exists.

* What are some known, safe, (or unsafe) scenarios to use the same key for signing and encryption?


  [1]: https://bitcoin.stackexchange.com/a/12556/1878