1. FileCrypter Developed by: Under the Guidance Ms.S.Maheswari, M.C.A.
T.Prabaharan
D.Suresh Kumar
Under the Guidance
Ms.S.Maheswari, M.C.A.
Dept. of B.C.A.

2. Hardware Configuration
FileCrypter
Hardware Configuration
Pentium Processor P4
256 MB RAM
5 MB of HDD space

3. Software Configuration
FileCrypter
Software Configuration
Windows XP SP-2
Visual Basic 6
ADO Library

4. FileCrypter
Abstract
The System 'FileCrypter' uses cryptography technique.
System enables user to Encrypt or Decrypt data/text based on a KEY.
Encryption & Decryption are done based on Rijndael Algorithm.

5. The System Consists of Two Modules.
FileCrypter
System Details
The System Consists of Two Modules.
Encryption Module
Decryption Module

6. FileCrypter Encryption Module:
Three steps are enclosed in this module.
KeyExpansion
Initial Round
Rounds

7. FileCrypter 1) Key Expansion:
This process involves getting of Round Keys.
Round keys are keys generated by Key Cycle process of Rijndael Algorithm.
Key Cycle process takes keys entered by user as its input.

8. FileCrypter 2) Initial Expansion:
Each byte is combined with round keys.
Bitwise XOR operation is used to combine the byte.
This process is so called ADD ROUND KEY, since addition of round key to data takes place.

9. FileCrypter
3) Rounds
Here three steps of process take place to ENCRYPT.
Sub Bytes- a linear substitution where each byte is replaced by verifying look up table.
Shift Rows- each row of state is shifted at a sequence.
Mix Column- operation on column, combing some bytes in each column.

10. FileCrypter Decryption Module:
The decryption process involves three steps.
Decryption is just a reverse process of encryption.
It involves Key Expansion, Reverse Rounding and Key decomposition.

11. FileCrypter 1) Key Expansion: 2) Reverse Rounding:
Same as Key Expansion that done in Encryption, (i.e.) Rounding Keys.
2) Reverse Rounding:
Based on key value the subtraction of bytes from each column.
Then rearranging of Rows in the data matrix takes place.

12. FileCrypter Finally, referring look-up table substitution performed.
3) Key Decomposition:
The Key Decomposition is the process of removing added Round Key from the data matrix.
This is the process of retrieval of original data in the system.

13. FileCrypter Data Flow Diagram Level 0 PF-Plain File PF/PT
PT-Plain Text
CF-Cipher File
CT-Cipher Text
PF/PT
SYSTEM
Key
- Flow of Encryption
CF/CT
- Flow of Decryption
Level 0

14. FileCrypter Module 1:Encryption Level 1 PT/PF KEY FS KE AR SB SR MC AR
PT- Plain Text
PF- Plain File
FS- Form State
KE- Key Expansion
AR-Add Round off
SB- Sub Byte
SR- Shift Row
MC- Mix Column
CT- Cipher Text
CP- Cipher File FS KE AR SB SR MC AR
Level 1
CT/CF