An information processing apparatus for processing encrypted data input as a byte stream with dynamically changing decryption keys includes the following elements. An encrypted data receiving section receives encrypted data input as a byte stream, identifies a range of data that is decrypted using an identical key as a unit of decryption, extracts information necessary for decryption from the byte stream, and outputs encrypted data sets in which the extracted information is added to segments of the encrypted data. An encrypted data decrypting section sequentially decrypts the encrypted data by queuing the encrypted data sets while distributing the encrypted data sets to generate plaintext data. A plaintext processing section processes the generated plaintext data.