Block encryption method and schemes for data confidentiality and integrity protection

Abstract

A block encryption method and schemes (modes of operation) that provide both data confidentiality and integrity with a single cryptographic primitive and a single processing pass over the input plaintext string by using a non-cryptographic Manipulation Detection Code function for secure data communication over insecure channels and for secure data storage on insecure media. The present invention allows, in a further aspect, software and hardware implementations, and use in high-performance and low-power applications, and low-power, low-cost hardware devices. The block encryption method and schemes of this invention allow, in yet a further aspect, encryption and decryption in parallel or pipelined manners in addition to sequential operation. In a yet further aspect, the block encryption method and schemes of this invention are suitable for real-time applications.

1 . An encryption method comprising the steps of: 
 receiving an input plaintext string comprising a message;    partitioning the input plaintext string into a plurality of equal-size blocks;    creating an MDC block that includes the result of applying a non-cryptographic Manipulation Detection Code (MDC) function to the plurality of the equal-size blocks;    making one and only one processing pass with a single cryptographic primitive over each of said equal-size blocks and the MDC block to create a plurality of hidden ciphertext blocks; and    performing a randomization function over said plurality of hidden ciphertext blocks to create a plurality of output ciphertext blocks.    
   
   
       2 . A decryption method that is the inverse of an encryption method, comprising the steps of: 
 presenting a string including ciphertext string for decryption;    partitioning said ciphertext string into a plurality of ciphertext blocks;    selecting n+1 ciphertext blocks from said plurality of ciphertext blocks representing n data blocks and one Manipulation Detection Code (MDC) block and performing a reverse randomization function on each of the selected n+1 ciphertext blocks to obtain a plurality of hidden ciphertext blocks;    making one and only one processing pass with a single cryptographic primitive that is the inverse of an encryption single cryptographic primitive over the plurality of hidden ciphertext blocks to obtain a plurality of plaintext blocks;    verifying integrity of the plaintext blocks using a non-cryptographic MDC function;    outputting the plurality of plaintext blocks as an accurate plaintext string if the integrity verification passes; and    outputting a failure indicator if the integrity verification fails.