The attorney-client privilege belongs to the client. It prevents the lawyer from being forced to testify about the client's communication, unless the client relinquishes his privilege. The lawyer also owes the client a duty of confidentiality to never reveal the client's secrets to anyone else without their permission. Almost always the answer is no.
Ethical laws and standards protect the secrecy of your relationships with your lawyer. In addition, it's very important to take advantage of those attorney-client protections to tell your lawyer everything you need to know to represent you. There's nothing that hurts your case more than allowing your lawyer to be taken by surprise in court or in negotiations because of something you were embarrassed to tell him. The ABA's Model Rules of Professional Conduct say that an attorney cannot allow a client to commit perjury.
If an attorney knows that a client's testimony in court is false, they must “take reasonable corrective action, which may include informing the judge.” In short, under the current rule, an attorney must keep the client's secret unless the client falsely testifies in court. Of course, a defendant in a criminal case doesn't need to testify at all. The prosecution must prove guilt beyond a reasonable doubt, whether the defendant testifies or not. Without the full story, according to the argument, attorneys cannot provide the best legal representation.
A defendant might well hide some of the facts from a lawyer if the lawyer had to tell those facts to the court. The movies usually show a lawyer who hires a client for free (at no cost) asking him for a dollar to close the deal. The lawyer interviewed his client, who said he can't remember what happened the night of the crime. In the “Mom and Dad” case, the defense attorney decided not to reveal the whereabouts of the witnesses.
The lawyer was then faced with the decision whether or not to reveal the whereabouts of “mom and dad”. The Model Code also states that a lawyer “may (but not “must”) disclose information relating to the representation of a client “to prevent the client from committing a crime or fraud with the reasonable certainty that it will cause substantial harm to the financial interests or property of another person and for whose promotion the client has used or is using the services of an attorney. We challenge you to tell us whether or not the lawyer in this situation should have kept the secret. A public defender was assigned to represent a man accused of robbing a “mom and dad” store.
For example, you are not protected if you approach a lawyer at a party and tell her your case. From the perspective of society, on the other hand, it is difficult to argue that the lawyer should be silent about “mom and dad”.