Updated: May 3
1. The Author of the Epistle is Saint Peter.
The author of the Epistle is Πέτρος, Ἀπόστολος Ἰησοῦ Χριστοῦ, Peter, an Apostle of Jesus Christ, 1 Peter 1:1. Jerome describes him in this way in his de Viris Illustribus: Peter, son of Jonas, brother of the Apostle Andrew, born in the village of Bethsaida in the province of Galilee, which is near the lake of Gennesaret, who was at first called Bar-Jona. Simon Bar-Jona, first called son of the dove, after the confession put forth with resolute courage, obtained anew the name of Peter, or כיפא/Cephas, on account of his constancy and fortitude. That is, he was Πέτρος/Peter, a living stone built upon a living stone, or Christ the petra/rock, and vivified by Him. For, Christ is the Πέτρα/Petra, 1 Corinthians 10:4,the stone laid, the precious corner stone of an altogether sure foundation, Isaiah 28:16. He was an Apostle of Jesus Christ, his rock, foundation, stone, which he confessed.
 See John 21:15, 17.  See Matthew 4:18; 10:2; Luke 6:14.  See John 1:44.  See Matthew 16:17.  Matthew 16:15-19: “He saith unto them, But whom say ye that I am? And Simon Peter answered and said, Thou art the Christ, the Son of the living God. And Jesus answered and said unto him, Blessed art thou, Simon Bar-Jona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven. And I say also unto thee, That thou art Peter (σὺ εἶ Πέτρος), and upon this rock (καὶ ἐπὶ ταύτῃ τῇ πέτρᾳ; note the change in gender) I will build my church; and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.”  See John 1:42; 1 Corinthians 1:12; 3:22; Galatians 2:9.  1 Corinthians 10:4: “And did all drink the same spiritual drink: for they drank of that spiritual Rock (πνευματικῆς—πέτρας) that followed them: and that Rock was Christ (ἡ δὲ πέτρα ἦν ὁ Χριστός).”
Dr. Dilday's Lecture: "2 Peter through Jude"