AES Encryption Decryption Online Tool

Information!

AES encryption decryption online tool which performs encryption or decryption of an input data based on the given modes (ECB, CBC, CFB or OFB) and key bit sizes (128, 192 or 256 bits) using AES algorithm.

The encryption/decryption with a cipher key of 128, 192, or 256 bits is denoted as AES-128, AES-192, AES-256 respectively.

AES Summary:

Name	Description
Block size	128 bits
key sizes	128, 192, 256 bits
Rounds	10, 12 or 14 (depending on key size)
Design principle	Substitution–permutation network
Modes	ECB: Electronic CodeBook CBC: Cipher-Block Chaining CFB: Cipher FeedBack OFB: Output FeedBack CTR: CounTeR OpenPGP: OpenPGP GCM: Galois/Counte EAX: encrypt-then-authenticate-then-translate
Designers	Vincent Rijmen, Joan Daemen
Also, known for	Rijndael A subset of the Rijndael block cipher Symmetric encryption (same key is used for encryption/decryption) Symmetric-key algorithm Symmetric ciphers A block cipher (AES uses block of 128 bit to divid data to cypher) United States Government’s Federal Information Processing Standard for symmetric encryption

What is AES Encryption?

The Advanced Encryption Standard (AES) is a block cipher that encrypts a 128-bit block (plaintext) to a 128-bit block (ciphertext), or decrypts a 128-bit block (ciphertext) to a 128-bit block (plaintext).

What is AES encryption/decryption flow?

AES encryption/decryption flows consists a back-to-back sequence of AES transformations, operating on a 128-bit State (data) and a round key. The flows depend on the cipher key length, where total transformation steps for encryption/decryption as follows -

AES-128 : 40 steps
AES-192 : 48 steps
AES-256 : 56 steps

Refer following encryption pseudo code -

Note -

It is assumed that the 10, 12, or 14 round keys are already derived (expanded) from the 'cipher key' and stored in round_key_encrypt[]
round_key_encrypt[0] stores the first 128 bits of the 'cipher key', which is used for the first XOR operation (aka round 0).


        # data is a 128-bit block to be encrypted.
        # The round keys are already stored in the round_key_encrypt[]
        tmp = addRoundKey(data, round_key_encrypt[0])
        for round = 1-9 or 1-11 or 1-13:
            tmp = subBytes(tmp)
            tmp = shiftRows(tmp)
            tmp = mixColumns(tmp)
            tmp = addRoundKey(tmp, round_key_encrypt[round])
        end loop
        tmp = subBytes(tmp)
        tmp = shiftRows(tmp)
        tmp = addRoundKey(tmp, round_key_encrypt[10 or 12 or 14])
        result = tmp

Similarly for decryption - follow 'Inverse Cipher', where steps reversed along with invert operations e.g. invSubButes(tmp), invShiftRows(tmp), invMixColumns(tmp)

Code/API references:

Developer Tool -kit & other tools:

Developer Tool-kit is a set of online developer tools that help get the results of various functionality on-the-fly and diagnose.

Various tools:

Other info:

Audience Type: Software developers and users
Abstract: Online Utility Tools
Version: v8.0.5
Date published: 2020-07-14
Date modified: 2021-11-28
Publisher: Rajendra Varma
Author: Rajendra Varma

Note - Since none of the user information does get stored on server, it is safe to use these tools

Online AES encryption decryption input/output: