Avodas Kochavim 2:7
A blasphemer is not liable to execution until he uses God’s unique name, which we pronounce “Adonai,” and curses that name using one of God’s names that may not be erased, as per Leviticus 24:16, “One who blasphemes the Name of God….” One is only stoned for blaspheming God’s unique name. If a person blasphemes another name of God, he violates a prohibition. Some maintain that one is only liable for blaspheming the Tetragrammaton (God’s four-letter name, spelled yud-hei-vav-hei), but the Rambam disagrees.
Avodas Kochavim 2:8
The prohibition against blasphemy is found in Exodus 22:27, “Do not curse God.”
The trial of a blasphemer proceeds as follows: When the witnesses are questioned, they euphemize God’s name, saying that they heard the defendant say, “May Yossi strike Yossi.” At the conclusion of the trial, any observers are removed and the judges cross-examine the witness of the greatest standing, instructing him to relate what he heard verbatim. At that point he relates explicitly what he heard the blasphemer say. The judges stand up and tear their garments; these may never be mended. The second witness says, “I also heard what he heard.” If there are any other witnesses, they must all say, “I heard likewise.”