1. CIPHERSET
GÖKSEL SARIKAYA

2. Content Introduction Definition DES ( Data Encryption Standart )
AES ( Advanced Encryption Standart )
Project Overview
Project Implementation
Examples
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3. Objectives
Security
We don’t want other people to see some informations openly, we want the informations to be hidden.
Saving some servers from overburden
In this way, servers don’t need to use their sources to make encryption and decryption operations.
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4. Cipher
When Julius Caesar sent messages to his generals, he didn't trust his messengers. So he replaced every A in his messages with a D, every B with an E, and so on through the alphabet. Only someone who knew the "shift by 3" rule could decipher his messages. And encryption and decryption so begin.
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5. Cipher ( Cont’d )
Data that can be read and understood without any special measures is called plaintext or cleartext.
The method of disguising plaintext in such a way as to hide its substance is called encryption.
Encrypting plaintext results in unreadable gibberish called ciphertext.
The process of reverting ciphertext to its original plaintext is called decryption.
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6. DES ( Data Encryption Standart )
Data Encryption Standard (DES) is a widely-used method of data encryption using a private (secret) key that was judged so difficult to break by the U.S. government that it was restricted for exportation to other countries.
DES applies a 56-bit key to each 64-bit block of data. The process can run in several modes and involves 16 rounds or operations.
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7. DES ( Cont’d )
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8. DES ( Cont’ d ) DES has two main process : Key Generator Process
64-bit Data Block Process
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9. Key Generator Process Get a 64-bit key from the user.
Perform PC-1 permutation on the 64-bit key. (The parity bits are discarded, reducing the key to 56 bits. Bit 1 (the most significant bit) of the permuted block is bit 57 of the original key, bit 2 is bit 49, and so on with bit 56 being bit 4 of the original key.) ( 56 bits ).
Split the permuted key into two halves.
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10. Key Generator Process ( Cont’d )
Perform one or two circular left shifts on both halves.
Iteration # Left Shifts
Perform PC-2 permutation on the shifted key bits. ( 48 bits )
Repeat all these processes until K[16] has been calculated.
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11. 64-bit Data Block Process
Get a 64-bit data block.
Perform the initial permutation on the data block.
Split the block into two halves. The first 32 bits are called Left[0], and the last 32 bits are called Right[0].
Expand the 32-bit Right[i-1] into 48 bits according to the bit-selection function below.
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12. 64-bit Data Block Process ( Cont’d )
Exclusive-or E(R[i-1]) with K[i].
Break E(R[i-1]) xor K[i] into eight 6-bit blocks. Bits 1-6 are B[1], bits 7-12 are B[2], and so on with bits being B[8].
Substitute the values found in the S-boxes for all B[j]. Start with j = 1. All values in the S-boxes should be considered 4 bits wide.
Take the 1st and 6th bits of B[j] together as a 2-bit value (call it m) indicating the row in S[j] to look in for the substitution.
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13. 64-bit Data Block Process ( Cont’d )
Take the 2nd through 5th bits of B[j] together as a 4-bit value (call it n) indicating the column in S[j] to find the substitution.
Replace B[j] with S[j][m][n].
Repeat these processes until all 8 blocks have been replaced.
Permute the concatenation of B[1] through B[8] with Permutation P.
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14. 64-bit Data Block Process ( Cont’d )
Exclusive-or the resulting value with L[i-1].
L[i] = R[i-1].
Loop back to 4.1 until K[16] has been applied.
Perform the final permutation on the block R[16]L[16].
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15. DES ( Cont’d ) Decryption
To decrypt, use the same process, but just use the keys K[i] in reverse order. That is, instead of applying K[1] for the first iteration, apply K[16], and then K[15] for the second, on down to K[1].
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16. AES ( Advance Encryption Standart )
The input and output for the AES algorithm each consist of sequences of 128 bits (digits with values of 0 or 1).
The Cipher Key for the AES algorithm is a sequence of 128, 192 or 256 bits. Other input, output and Cipher Key lengths are not permitted by this standard.
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17. AES ( Cont’d )
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18. AES ( Cont’d )
At the start of the Cipher, the input is copied to the State array using the some conventions. After an initial Round Key addition, the State array is transformed by implementing a round function 10, 12, or 14 times (depending on the key length), with the final round differing slightly from the first Nr-1 rounds. The final State is then copied to the output .
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19. AES ( Cont’d )
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20. AES ( Cont’d ) AES has four main processes : SubBytes ShiftRows
MixColumns
AddRoundKey
Subbytes , bytelarin yer degistirmeleri. S-box’lara gore.
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21. SubBytes
The SubBytes() transformation is a non-linear byte substitution that operates independently on each byte of the State using a substitution table (S-box).
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22. SubBytes ( Cont’d )
For example, if S1 , 1 {53}, then the substitution value would be determined by the intersection of the row with index ‘5’ and the column with index ‘3’ in the table. This would result in S1 , 1 having a value of {ed}.
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23. ShiftRows
In the ShiftRows() transformation, the bytes in the last three rows of the State are cyclically shifted over different numbers of bytes (offsets). The first row, r = 0, is not shifted.
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24. MixColumns
The MixColumns() transformation operates on the State column-by-column, treating each column as a four-term polynomial.
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25. AddRoundKey
In the AddRoundKey() transformation, a Round Key is added to the State by a simple bitwise XOR operation. Each Round Key consists of Nb words from the key schedule
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26. Key Expansion
The AES algorithm takes the Cipher Key, K, and performs a Key Expansion routine to generate a key schedule. The Key Expansion generates a total of Nb (Nr + 1) words: the algorithm requires an initial set of Nb words, and each of the Nr rounds requires Nb words of key data.
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27. Key Expansion ( Cont’d )
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28. Project Overview Clean Text Encrypted / Decrypted Text Set Algorithm
Set KEY
Encrypt / Decrypt
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29. Project Overview Object Oriented Structure Modular Easily Expandable
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30. Project Overview
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31. Project Overview Command Packets:
1-SetKey: keylength, key, Dir : pc -> kit
2-ACK_SetKey: ACK for getting key. kit -> pc
3-NACK_SetKey, NACK for getting key. kit -> pc
4-SetAlgorithm: algorithmType , pc -> kit
5-ACK_ SetAlgorithm , kit -> pc
6-NACK_ SetAlgorithm , kit -> pc
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32. Project Overview 7-Encrypt : datalen, data . pc -> kit
8-ACK_ Encrypt, kit -> pc
9-NACK_ Encrypt, kit -> pc
10-Decrypt: datalen, data. pc -> kit
11-ACK_Decrypt kit -> pc
12-NACK_Decrypt kit -> pc
13-GetEncryptedData : encrypteddatalen, encrypteddata. kit -> pc
14-ACK_ GetEncryptedData, pc -> kit
15-NACK_ GetEncryptedData, pc -> kit
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33. Project Overview
16-GetDecryptedData: decrypteddatalen, decrypteddata kit -> pc
17-ACK_GetDecryptedData pc -> kit
18-NACK_GetDecryptedData pc -> kit
19-Rescyn, pc -> kit
20- ACK_Rescyn kit -> pc
21- Error: error code, kit -> pc , pc -> kit
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34. Data Structure DELIMETER ( 0x30)(0x30) COMMAND DELIMETER ( 0x30)(0x30)
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35. Data Structure Command Packets Structure For all command types:
1- Command type (1 byte)
2- Length (2 byte) Total length of packet
3- Special area for commands ( n bytes )
Special areas for special commands:
1-SetKey:
1 byte keylength,
keylength bytes key.
2-SetAlgorithm:
1 byte algorithm type.
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36. Data Structure 3-Encrypt 4-Decrypt 5-GetEncryptedData :
2 byte datalen,
2 byte sequence number
datalen bytes data
4-Decrypt
5-GetEncryptedData :
2 byte encrypteddatalen,
encrypteddatalen bytes encrypteddata
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37. Data Structure No special area 6-GetDecryptedData: 7-Rescyn, 8-Error
2 byte decrypteddatalen,
2 byte sequence number
decrypteddatalen bytes decrypteddata
7-Rescyn,
No special area
8-Error
4 byte errorcode
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38. Hardware – MCF5282
MCF5282 Integrated ColdFire Version 2 Microcontroller
The MCF5282 is the first microcontroller based on Freescale Semiconductor's 32-bit ColdFire core integrated with Ethernet, Flash and CAN. This device offers advanced communications features, a rich peripheral set and a variety of supporting software and development tools.
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39. Hardware – MCF5282
V2 ColdFire core delivering 76 (Dhrystone 2.1) MIPS at 80 MHz running from Cache/RAM  (max running from internal flash 66 MIPS)
512KB embedded flash memory
64 Kbytes of static RAM
10/100 Ethernet MAC
Cache for external access support
Address decode and chip selects
CAN 2.0B controller area network interface with 16 message buffers
Three UARTs with DMA capability
8-channel 10-bit queued analog-to-digital converter (QADC)
Four 32-bit timers with capture, compare and DMA capability
Eight 16-bit timer channels for capture, compare, and pulse width modulation
Four periodic interrupt timers (PITs)
I2C bus controller
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40. PROJECT IMPLEMENTATION
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41. THANK YOU FOR YOUR PATIENCE...
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