1
$\begingroup$

Referring to the AES specification:

https://nvlpubs.nist.gov/nistpubs/fips/nist.fips.197.pdf

Printed pages 35-37...

The first detailed walkthrough is encryption, the second is decryption.... I don't understand what is the third, "equivalent inverse cipher (decrypt)"?

How can there be two decryption techniques?

Improve this question
$\endgroup$
1
  • $\begingroup$ Read section 5.3.5 of the linked specification (pg. 23 ff.). $\endgroup$
    – yoyo
    Commented Feb 13, 2023 at 23:32

1 Answer 1

Reset to default
3
$\begingroup$

You are correct that the third example in the AES specification (printed pages 35-37) is not a decryption technique, but rather an "equivalent inverse cipher" that demonstrates the inverse of the cipher's encryption algorithm.

there is only one decryption technique in AES, which is the inverse of the encryption algorithm. The third example in the specification is simply another way to express the inverse of the encryption algorithm, and it is not a separate decryption technique.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.