link to dowload the image:

http://www.mediafire.com/download.php?950rob1nw0xgzbu

Hello my friends and other people. This time i post some pictures and your try to find the message in tree of six picture

Good luck!!!

link to dowload the image:

http://www.mediafire.com/download.php?950rob1nw0xgzbu

Iv = It is a starting vector for different types of cryptographic systems. This can generate a randomly.

Both encryption and decryption use the substitution method to generate our XOR'ed ciphertext. Where the internal state of the algorithm is 512-bit and 8 states are divided by 32 bits each. Different states vectors are modified during the execution of the algorithm.

Variable g is used to cycle the different values of both counters as the vector x, and to generate new values for the vector x and iterating using "g" of the previous two iterations

Here the equations:

"<<" Means that there is a tour of some bit to the left

">>" Means that there is a tour of some bit to the right

Here is a picture of a first round generating 8 blocks of "Si"

One of the biggest advantages of this algorithm is the use of a 128-bit key that grabs one of the best sytems about execution speed, different blocks also constantly change. The attacks is more difficult to perform in against a random key.

The strength is the division of the keys in 8 to modify the state variables, for different types of attacks such as statistical and brute force

http://www3.iam.metu.edu.tr/iam/images/6/6a/Tarkanolcuogluterm.pdf

http://cr.yp.to/streamciphers/rabbit/desc.pdf

https://tools.ietf.org/html/rfc4503

http://reference.kfupm.edu.sa/content/r/a/rabbit__a_new_high_performance_stream_ci_66630.pdf

http://en.wikipedia.org/wiki/Initialization_vector

Greats, This week we will be talking about: Block Cipher, spcifically Hierocrypt.

This Hierocrypt have two many different fomrs with small differences:

and was created by

These encryption algorithms were presented to the NESSIE project but were not selected, but it is still highly recommended by the Japanese government used by CRYPTREC.

The size of blocks:

The PlainText has to be the same size of the block

The size of keys: **128 bits vs ****128, 192, or 256 bits.**

The number of rounds of encryption: **6.5 vs 6.5,7.5 or 8.5**

The **Hierocrypt-3** is more complex.

This **Hierocrypt** use a substitution-permutation network structure.

This algorithm starts by transforming a 64-bit plaintext a function of X (64) then substitution is performed using a key by dividing the 64 bits into 8 blocks, and repeating the process of replacing in each of them.

This we can check in the following pdf: LINK

As mentioned above this algorithm uses 6 permutations to encrypt the message. And in each of the permutations do exactly the same.

1-. The X(64) if is the first permutation is the same of Plain text. After this, Use the substitution method Xor and divide those 64 bits into small blocks of 8 bits.

2-. Each S-box will be used and the 64 bits will be separated in two blocks of 32 bits.

3-. Then a function is perfomed tocause slight diffusion so that is harder to detect patterns of sequence.

4-. We use two 32-bits keys for the Xor substitution method and also We merge the 64-bit.

5-. With this input. We repeat step 1

6-. After that, we perform a function that cause strongest diffusion so that is harder to detect patterns in the sequence, and we created a matrix of 2x2. then marge the 64-bit.

7-. This output X (64) is the new entry in the next permutation.

8-Do this steps all 6 permutations.

9-. Finally encrypts X (64) with a 64-bits key to get our ciphertext.

1-. The design and structure are much larger than the Feistel structure and takes longer**.**

2-. The Diffusion´s widht is twice of the Feistel structure.

3-. Input size limits.

1-. Fast execution

2-. Better security against statistical attacks

Special thanks to Esteban Sifuentes for checking my Orthography.

Special thanks to Esteban Sifuentes for checking my Orthography.

Reference:

http://en.wikipedia.org/wiki/Rijndael_S-box

http://en.wikipedia.org/wiki/Hierocrypt

http://es.wikipedia.org/wiki/Criptograf%C3%ADa

link de pdf de las imagenes LINK

http://en.wikipedia.org/wiki/Feistel_cipher

http://en.wikipedia.org/wiki/Advanced_Encryption_Standard

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