Who exactly knew that Chancellor Palpatine was Darth Sidious?

Question

There are only few people who know it. I can include the following people:

• Count Dooku/Darth Tyranus - I'm sure he told Dooku, because he played such a huge role in Palpatine's plans and the war, so he would always have to know what's going on. Plus by the look on his face when Palpatine told Anakin to kill him, he looked at him like he knew who he was.

• Mas Amedda - I think he knew, because Palpatine would have told him so they could work together in the Galactic Senate to get whatever results Palpatine wanted, plus in an episode of The Clone Wars, Palpatine says something to him about his plan coming together.

• Sly Moore - I think she had as much of a major role with Palpatine and the Galactic Senate as Mas Amedda did. During the speech of the Emperor in Revenge of the Sith, she was there.

Did Darth Maul and General Grievous know that Palpatine is Darth Sidious?

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Note: the idea for this question came from http://boards.theforce.net/threads/who-exactly-knew-chancellor-palpatine-was-darth-sidious.50009052/

Answer 1

Besides those you mentioned, a few others knew his identity.

• Ahsoka Tano:

The shadow was almost certainly one of the dark side’s creatures. Ahsoka had no idea what sort of thing it might be, but whatever it was couldn’t be that powerful, because it hadn’t been able to track down Hedala. That ruled out Palpatine himself, not that the Emperor could just show up on a planet without causing a great deal of alarm. (Ahsoka)

• Eneb Ray:

• While it's never explicitly stated in the canon that Maul knew, it's very likely he made the connection at some point, given that he recognized the Empire as his enemy. He did know in the Legends continuity, though.

What then if- beyond contemplation- something should befall his Master? Unlike Darth Sidious, who masqueraded as Republic Senator Palpatine and debated complex issues in the Senate, Maul lacked a secret identity. With his yellow eyes and horned head a black-and-red mask of arcane sigils, it was all he could do to prowl the fringes of The Works in the dead of night without instilling fear in nearly every being whose gaze he caught. (Darth Plagueis)

• Yoda, Windu and the various other Jedi who learned his identity in Revenge of the Sith, as well as Luke Skywalker.

• Tarkin had his suspicions:

Tarkin may also have determined that Vader was a Sith. If so, it followed that he accepted that Sidious was Vader’s dark side Master. (Tarkin)

Grievous did not know.

Answer 2

Most of Palpatine's Executive Office staff would have to be aware of his position. Aside from Mas Amedda and Sly Moore, Sate Pestage had a great deal of involvement in the creation of the Empire and was instrumental; he was Palpatine's most trusted advisor for years.

Having your entire staff in on your Sith identity would be critical to maintaining secrecy. Oftentimes Palpatine had to make contact with those on the CIS. He would have to leave on spontaneous trips and keep his identity secret. Everything he did in his office was essential to executing the Grand Plan, his entire staff would've been involved in helping reach that aim. Different members may have been involved to different extents, but anyone knowing the Chancellor's whereabouts and work procedures would know he was much more than a Chancellor.