The Association of Criminals, Subversives and Insurgents (ACSI, in short) are big fans of RSA encryption, and recently published a list of their members' public keys. For reasons unbeknownst to us, they have a habit of signing their messages with multiple private keys before encrypting the signed message with a single public key.
Using one of our portable False Base Stations, we captured one of ASCI's encrypted, doubly-signed, super secret alphabetic passwords (along with the public key used to encrypt it). We need you to figure out who signed the password, and what the password is by decrypting && unsigning the captured RSA transmission.
Flag format: IRS{Name of first person to sign_Name of second person to sign_The password}
Challenge description extemporised by @main
Author: @syralie
- [Encryption: M^e % n = C] [Decryption: C^d % n = M] [Signing: M^d % n = S] [Unsigning S: S^e % n = M]
- Obtaining a decryption key (d) is not necessary at any point in this challenge.
- try to read the bolded words