9. Problem Statement
To develop “NCRPT ” application is used to secure the data at rest on Android . In
which password based encryption method is used along with lightweight HummingBird-
2 algorithm for making application inaccessible to unauthorized users.
9
07/11/14
10. Humming Bird-2 Algorithm
A. Initialization Phase:-
HB-2 operates on 16-bit blocks, so the following variables K, R and IV are
accessed as vectors of 16- bit words.
K = (k1, k2, k3, k4, k5, k6, k7, k8),
R = (R1, R2, R3, R4, R5, R6, R7, R8),
IV = (IV1, IV2, IV3, IV4)
11. Humming Bird 2- Algorithm
16 bit Keyed permutation
S(y) =S1(y0) | S2(y1) | S3(y2) | S4(y3)
L(y) = y ( y <<< 6) ( y<<< 10)
f(y) = L(S(y)).
where S(y) indicate computation of four
S- Boxes and L(y) is the linear
transformation
16. Humming Bird 2- Decryption
Decryption of a single word of plain text requires same initialization as used in
encryption.
u3= WD16-1(input ⊖ R1 , k8, k7, k6, k5 )
u2= WD16 -1( u3 ⊖ R4, k4^R8, k3^R7, k2^R6, k1^R5)
u1=WD16-1 (u2 ⊖ R3, k8^R8, k7^R7, k6^R6, k5^R5)
plain_text = WD16 -1 (u1 ⊖ R2 , k4, k3, k2, k1 ) R1 where is subtraction modulus
65536 (216)
WD16 -1 (y, a, b, c, d) = f-1 (f-1 (f-1 (f-1 (y d) c) b) a)
S-1 (y) =S1-1 (y0) | S2-1 (y1) | S3-1 (y2) | S4-1 (y3)
L-1 (y) = y ( y <<< 2)^ ( y<<< 4)^ ( y<<< 12)^ ( y<<< 14) f-1 (y) = S-1 (L-1 (y)).
17. System Overview
A.Password based key generation.
B. Application overview
The application has been developed in C language and uses JNI (Java Native Interface)
for calling this function in Android.
C. The application works in following way:
1. The user opens the application and authenticates using password.
2.User can select encrypt button to encrypt the file stored in SD card of smart phone.
3.If the user selects to decrypt the file before encryption is done, the application prompts that file is already
decrypted.
4. Contents in SD card can be stored in the encrypted form .
18. Mathematical Model
Let, S={s,e,X,Y,F } Where S is a system of data from various sources.
S consist of, s = distinct start of system, e = distinct end of s
X = {X1,X2,X3,X4 } Input of system,
we consider plain text is the input.
Y = output of system
F = algorithms or functions having certain computation time
Let, s = { Crypographic application} X={password,plaintext)
mathematically have:
(plain text ,Key)Encrypt()(cipher text,Key)Decrypt()(plaintext)
Cipher text= Encrypt(K, P) Plain text = Decrypt(K,C))
e = output is secure encryption-decryption process.
F = Password based key generation method -{Humming bird 2}
Encrypt()= convert plain text to cipher text
Decrypt()=convert cipher text to plan text
19. Strength of Algorithm
1.From the security analysis it is found that Hummingbird-2
is resistant against linear cryptanalysis up to 12 rounds of f.
2. The four rotations in the initialization phase provides strong resistance
against related key attacks.
3.The algebraic degree and branch number of S-Boxes protects
against different forms of algebraic distinguishing attacks.
4.If more than 264 invocations of the encryption function are done with the same key,
a birthday condition in the internal state may arise.
20. Conclusion & Future Scope
Use of smart phones is increasing for application involving confidential data.We have developed a
new tool for securing the Information at rest in Android Platform that uses a lightweight authenticated
encryption algorithm, Hummingbird-2, that is believed to be resistant to most of the standard attacks on
block ciphers and stream ciphers. password based authentication. But, password guessing can make the
application vulnerable expose to damage with the sensitive information. As a conclusion the developed tool
Is faster than other tools which are based on traditional cryptographic schemes and meets the compactness
requirements.
So in our future work, we will focus on hybrid techniques for generation of the encryption key to
make the application more secure. We can also make use of the biometrics which is used to generate key
for the encryption with the help of random number generator to make the key complex.
21. Refferences
[1]David Stites and Anitha Tadimalla , “A Survey Of Mobile Device Security: Threats, Vulnerabilities
and Defenses”, University of Colorado at Colorado Springs, December 14, 2011.
[2] Michael E. Whitman and Herbert J. Mattord , “Principles of Information Security”, Fourth Edition.
[3] BS Reporter, March 18, 2011 http://www.business-standard.com/article/ttechnology/one-in-two-i
ndians-victim-of-mobile-phone-loss-norton- 11031800069_1.html
[4] John, Jacob. "Cryptography for Resource Constrained Devices: A Survey", International Journal
on Computer Science & Engineering,2012.
[5] Federal Information Processing Standards Publication 197, AES, November 26
[6]Federal Information Processing Standards Publication 46-2,DES, December 30
[7] Gregory Leander, Christof Paar, Axel Poschmann, and Kai Schramm. New lightweight des
variants. In Fast Software Encryption – FSE 2007, volume 4593 of Lecture Notes in Computer Science,
pages 196{210. Springer, 2007
[8] [8]Sufyan Salim Mahmood AlDabbagh, Imad Al Shaikhli, Lightweight Block Ciphers: a Comparative Study,
Journal of Advanced Computer Science and Technology Research Vol.2 No.4, November 2012, 159-165
[9] Jacob John, Performance Analysis of New Light Weight Cryptographic Algorithms,
IOSR Journal of Computer Engineering (IOSRJCE) ISSN: 2278-0661, ISBN: 2278-8727
Volume 5, Issue 5 (Sep-Oct. 2012), PP 01-04.
[10] Mickael Cazorla, Kevin Marquet and Marine Minier Universite de Lyon, INRIA INSA-Lyon,
Survey and Benchmark of Lightweight Block Ciphers for Wireless Sensor Networks.
of Electrical and Computer Engineering University of Waterloo Waterloo
