It does not seem to be the case that MyEtherWallet.com is supporting read function sender restrictions such as onlyOwner modifiers or similar, so basically it is impossible to restrict particular function reads to certain groups/tiers of people. Why is this not an option? I believe it should be possible to confirm similar to write functions by accessing a wallet through one of the many options.
onlyOwner cannot be enforced on
pure (or the deprecated
constant) functions, since when reading from outside, any view-able data is public. A simple read operation does not involve a transaction, and thus does not have a
I imagine calling a view function with an
onlyOwner limitation from another contract might fail, however, but there is no way to prevent it from web3.
Edit: As smarx points out, it is possible to set
msg.sender for a view function call, but perhaps not through MyEtherWallet. In any case, this is optional and should not be relied upon for security. Any data on the blockchain should be treated as public and readable by all.