# A3 **Deadline:** Tuesday, 02/24/26, 11:59 pm *This assignment may be done as individuals or with a partner (I recommend with a partner). If you choose to work with a partner, you should submit one solution.* A3 and A4 are a two-part assignment. This first part (A3) is due on February 24. The second part (A4) is due March 3. I expect A4 to take longer than A3, so you might want to get started on that one early. Unfortunately for you, I'm not going to post A4 on the website, I'm only going to give you an encrypted copy of A4. Your task for this week is to decrypt next week's assignment. The following information may be useful: I encrypted A4 with hybrid encryption using RSA-2048 with OAEP using SHA-256 and AES-256 in GCM. The starter files for A3, which include the RSA secret key (formatted in the PKCS8 standard), an encrypted copy of the AES key (formatted as a binary file), and the AES-encrypted A4 (formatted as a zip file), are available <a href="a3-starter.zip">here</a>. The randomly-generated IV used during AES encryption is 0x5A27710DB8004E0C4CF00573F5665290. Hint: You may use any cryptographic library of your choice to implement the decryption, but you might find it helpful in the future if you use the same language as you plan to use for your project. **What to submit:** For A3, you should submit the following three files: (1) the source code for a program that reads in the starter files and writes a (decrypted) file a4.zip, (2) a copy of the decrypted assignment handout a4.pdf (which you can find in the decrypted zip file), and (3) a plaintext file named feedback.txt that answers the following four questions: 1. How long did you spend on this assignment? 2. How did you use AI on this assignment? 3. Did you discuss problems with any other students? If so, who? 4. Any comments or feedback? Things you found interesting? Things you found challenging? Things you found boring?