Question: In the context of USAT decryption calculation, what is the purpose of converting the ciphertext C to an integer ciphertext representative 'c' using the OS2IP function?
Option 1: To generate a hash for message authentication
Option 2: To facilitate RSA decryption by transforming byte string to numerical representation
Option 3: To compress the ciphertext for efficient storage
Option 4: To encrypt the plaintext for an additional security layer
Explanation: The OS2IP function converts a byte string (ciphertext C) into a numerical representation (integer ciphertext representative 'c'). This is crucial because RSA decryption algorithms operate on numbers, not byte strings. Thus, this step transforms the ciphertext for processing by the RSA decryption algorithm, which requires numerical inputs.