A sealed warrant is not a "secret warrant." It's to avoid tipping off the subject of an active investigation: "The warrant also ordered Google not to disclose the search to anyone."
Nothing in the 4th amendment says that warrants must be publicly broadcast. The purpose is to insert a judge as a check on the search power of the police. This warrant was validly issued by a U.S. District Court.
A sealed warrant may, however, run afoul of the 6th amendment right to confront your accusers if they are sealed to protect confidential informants. In that circumstance, they can be challenged by defense counsel in a prosecution in which the evidence is used. There are also time limits. See: http://www.vaed.uscourts.gov/courtdocs/LocalRulesEDVA.html#c... (Criminal Rule 49(b)(3)).
"Secret" has a specific historical implication, which is that in prosecutions based on secret evidence, the accused was not able to evaluate and challenge that evidence. Sealed warrants cannot be used to indefinitely keep targets from confronting the evidence against them.
Nothing in the 4th amendment says that warrants must be publicly broadcast. The purpose is to insert a judge as a check on the search power of the police. This warrant was validly issued by a U.S. District Court.
A sealed warrant may, however, run afoul of the 6th amendment right to confront your accusers if they are sealed to protect confidential informants. In that circumstance, they can be challenged by defense counsel in a prosecution in which the evidence is used. There are also time limits. See: http://www.vaed.uscourts.gov/courtdocs/LocalRulesEDVA.html#c... (Criminal Rule 49(b)(3)).