Is it permissible for a government employee to file a complaint against corruption in his workplace without revealing his identity?

The Prophet, peace and blessings be upon him, clarified the way to deal with evil and denounce it in his saying: "Whoever among you sees an evil, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith." If you fear harm from denouncing the evil directly, and they are persistent in deception and unlawfully consuming wealth, you can inform the authorities responsible for workplace violations without disclosing your name, so that the responsible authority can monitor, change the evil, and remove the injustice. By doing so, you would have advised and fulfilled your duty, as Allah Almighty says: "O you who have believed, upon you is [the responsibility of] yourselves. No harm will come to you from one who has gone astray when you have been guided. To Allah is your return all together; then He will inform you of what you used to do."