An efficient implementation of RSA algorithm for speech data encryption and decryption. At first, five hundred Bangla speech words were recorded from six different speaker and stored as RIFF (.wav) file format. Then our developed program was used to extract data from these words and this data were stored in a text file as integer data. Finally, we used our implemented program to encrypt and decrypt speech data.

1. Md. Ariful Hoque
Roll No: MSc 140202
Discipline : CSE
Khulna University

2. Data communication.
Vital role of Cryptography.
Phone communication.
E-commerce.
Pay-TV.
Transmitting financial information.
Video Conferencing.
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3. Cryptosystem.
Encryption
Decryption
Symmetric cryptosystem.
RSA cryptographic algorithm.
Uses a pair of related keys -
Private key
Public key
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4. Record 500 Bangla speech words.
Extract data.
Stored in a text file as integer data.
Encrypt and decrypt.
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5. Speech
Word
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Recording of Bangla speech words.
Recorded as wav file.
Sampling rate 8.00 KHz.
Coded in 8 bits PCM.

6. Speech
Word
Preprocessing
and
Data
Extraction
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Discard 58 bytes from beginning.
Extract require voiced data.
Contain silence, unvoiced and voice.
Stored in a text file.

7. Speech
Word
Preprocessing
and
Data
Extraction
Public
key
{e, n}
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8. Speech
Word
Preprocessing
and
Data
Extraction
Encryption
Process
8
Public
key
{e, n}

9. Speech
Word
Preprocessing
and
Data
Extraction
Encryption
Process
Private
key
{d, n}
Public
key
{e, n}
9

10. Speech
Word
Preprocessing
and
Data
Extraction
Encryption
Process
Decryption
Process
Public
key
{e, n}
10
Private
key
{d, n}

11. Speech
Word
Preprocessing
and
Data
Extraction
Encryption
Process
Decryption
Process
Original
Speech
Word
Private
key
{d, n}
Public
key
{e, n}
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12. 12

13. 13
Random
Number
Generator

14. 14
Random
Number
Generator
Rand FIFO

15. 15
Random
Number
Generator
Rand FIFO
Primality
Tester

16. 16
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO

17. 17
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)

18. 18
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)
n

19. 19
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)
gcd(e, ∅(n))=1
1<e< ∅(n)
n

20. 20
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)
gcd(e, ∅(n))=1
1<e< ∅(n)
e n

21. 21
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)
gcd(e, ∅(n))=1
1<e< ∅(n)
e.d =1mod ∅(n
0 ≤d ≤n
e n

22. 22
Random
Number
Generator
Rand FIFO
Primality
Tester
Prime FIFO
N=p*q
∅(n)=(p-1)(q-1)
gcd(e, ∅(n))=1
1<e< ∅(n)
e.d =1mod ∅(n
0 ≤d ≤n
d e n

23. 23
 Public key e n

24. 24
e n
d
n
 Public key
 Private key

25. 25
M

26. 26
M
e
n

27. 27
M
e
n
Modular Exponentiation
Me mod n

28. 28
M
e
n
Modular Exponentiation C
Me mod n

29. 29
C

30. 30
C
d
n

31. 31
C
d
n
Modular Exponentiation
Cd mod n

32. 32
C
d
n
Modular Exponentiation M
Cd mod n

33. 33
Input: A, B, n
Output: E = AB mod n
LR binary method
E <= 1;
for i = k-1 to 0
If Bi =1
E <= A*E mod n
end if
if i ≠ 0
E <= E*E mod n;
end if
end for
return E;

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35. Objective.
500 speech words recorded.
Saved as .wav format.
Extracted integer data.
Taken txt file as input.
Produce unreadable message.
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36. RSA algorithm used to encrypt and decrypt.
M lies in the range .
Encrypt 500 word at a time.
Limitations.
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37. Thanks To All
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