1. BLOWFISH ENCRYPTION ALGORITHM Presented by: Simranjit Singh (11713432) M.Tech (CSE) LPU

2. BLOW-FISH ENCRYPTION SYMMETRIC KEY ENCRYPTION LIKE A PASSWORD THAT NEED TO KEPT SECRET FROM EVERYONE OTHER THAN SENDER AND RECEIVER. BLOCK CIPHER NUMBER OF ROUNDS ARE 16 MICROPROCESSOR 32 BIT

3. Message... 64 bit Blow Fish Key P-array & S-Box Cipher Text

4. P-ARRAY These are 18 boxes ( p1, p2, p3 … p18) Each box is of 32 bits

5. S-BOX There are 4 different S boxes (S1, S2,S3 and S4) Each of 32 bit array Each box has 256 entries BLOWFISH\constants.txt (8 bits) (32 bits)

6. Start M/2 = ML and MR i=1 ML =ML ⊕ Pi MR = F(ML) ⊕ MR Swap ML and MR i=i+1 i<=16 Swap ML and MR ML =ML ⊕ P17 MR =MR ⊕ P18 Recombine ML and MR End FLOW CHART

7. M F 14 MORE ROUNDS F M

8. Function - F 32 bit ML block S1 S2S3 S4 + + + (8 bits) (32 bits)

9. USE OF S-BOX 01 1011 01 01 Row index 1011Column index 12...11...15 1... 2 5 2ffd72db... 15...

10. WHAT ABOUT KEY ?????

11. KEY SCHEDULING Step 2: Repeatedly cycle through the key bits until the entire p-array has been XORed with key bits Step 3: Encrypt using blowfish Step 5: Encrypt the output of step 3 NOTE: Total 521 iteration are required

13. THANKS