Skip to content

An AES implementation of a CTR block cipher using a CBC-MAC along with an ECB implementation for comparison

Notifications You must be signed in to change notification settings

alexmasi/Block-Cipher-CTR-ECB

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

6 Commits
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

Block-Cipher-CTR-ECB

An AES implementation of a CTR block cipher using a CBC-MAC along with an ECB implementation for comparison.

Getting started

In the libdcrypt directory, run

$ ./configure

After successful configuration build the executables by running

$ make

Now the AES Pseudo Random Permutation is avaliable for use in the src executables. Finally in src run

$ make

Usage

In the src directory, run

$ ./keygen keyfile

to generate a 64-bit key saved to keyfile. To encrypt, run

$ ./ctr_encrypt keyfile plaintext ciphertext

to encrypt the content of plaintext to a file named ciphertext. To decrypt, run

$ ./ctr_decrypt keyfile ciphertext plaintext

to decrypt the content of ciphertext to a file named plaintext.

Likewise use ecb instead of ctr to encrypt using the Electronic Code Book (ECB) mode of operation for the AES block cipher instead of the Counter (CTR) mode of operation. Note that the CTR mode is Chosen Plaintext Attack (CPA) secure while the ECB mode is not. Also the CTR mode implementation includes a Cipher Block Chaining Message Authentication Code (CBC-MAC) along with the standard encryption to upgrade the scheme from CPA secure to Chosen Ciphertext Attack (CCA) secure making the ctr suite secure against man-in-the-middle tampering to the ciphertext. Thus the ctr suite is more secure and desirable than the ecb suite.

Examples

In the examples directory there are bitmap images encrypted with both ctr mode and ecb mode to show how inferior ecb is when encrypting files. Notice that the circles.bmp image is still very clear with ecb due to no randomization of state tracking in the mode making the encryption not CPA secure. The ctr mode is CPA secure and CCA secure (due to the CBC-MAC) making the bmp image encryption appear much more "random".

Authors

  • Alex Masi
  • Walter Krawec

Acknowledgments

  • Thank you:
    • Professor Walter Krawec
    • Libdcrypt
  • Originally created for an Honor's Conversion in CSE 4702: Intro to Modern Cryptography at the University of Connecticut taught by Professor Walter Krawec.

About

An AES implementation of a CTR block cipher using a CBC-MAC along with an ECB implementation for comparison

Topics

Resources

Stars

Watchers

Forks

Releases

No releases published

Packages

No packages published