Variable Length Hash Algorithm Using RC6

Hash_RC6 – Capricious Breadth Assortment Algorithm appliance RC6

  • Kirti Aggarwal
  • Dr. Harsh K. Verma

 

ABSTRACT

In this paper, we present a assortment algorithm appliance RC6 that can accomplish assortment bulk of capricious length. Assortment algorithms comedy above allotment in cryptographic aegis as these algorithms are acclimated to analysis the candor of the accustomed message. It is accessible to accomplish assortment algorithm appliance symmetric block cipher. The capital abstraction abaft this is that if the symmetric block algorithm is defended afresh the generated assortment action will additionally be defended [1]. As RC6 is defended adjoin assorted beeline and cogwheel attacks algorithm presented actuality will additionally be defended adjoin these attack. The algorithm presented actuality can accept capricious cardinal of circuit to accomplish assortment value. It can additionally accept capricious block size.

Keywords: Cryptography, Symmetric Encryption, Agee Encryption, Abstracts Integrity, Authentication, Confidentiality, Non-Repudiation, Admission Control, Hash, RC6

INTRODUCTION

Cryptography is the adeptness of befitting bulletin defended anatomy others while sending advice amid participants (Confidentiality). There are abounding cryptographic algorithms categorized as symmetric encryption algorithm and agee encryption algorithm. Symmetric encryption algorithm is the one that use aforementioned aggregate key from encryption and decryption, while agee algorithm is the one that use altered keys from encryption and decryption.

With the Confidentiality cryptography additionally accommodate alternative casework accepted as abstracts integrity, authentication, non-repudiation, admission ascendancy etc. Abstracts Candor is acceptable that abstracts accustomed is aforementioned as beatific by the sender. Affidavit is the adeptness to assure that communicating affair is who that it claims to be. Non-Repudiation is the blockage adjoin the abnegation by entities circuitous in the communication. Admission Ascendancy is the blockage adjoin the crooked use of assets [2].

Figure 1. Fundamental of Cryptography

Hash Function

A cryptographic assortment action is any algorithm or subroutine that maps ample abstracts sets of capricious breadth to abate abstracts sets of a anchored length. The ethics alternate by a assortment action are alleged assortment values, assortment codes, assortment sums, checksums or artlessly hashes.

Where h has anchored length. An (accidental or intentional) change to the abstracts will (with actual aerial probability) change the assortment value.

For a assortment action to be advised secure, it charge be computationally absurd to acquisition has a predefined assortment bulk and analogously it charge be computationally absurd to acquisition two letters accepting aforementioned assortment value.

RC6

RC6 is a symmetric block blank based on RC5 and advised by Rivest, Sydney, and Yin for RSA aegis [3]. Like RC5, RC6 is a parameterized algorithm area the block size, the key size, and the cardinal of circuit are variable; again, the high absolute on the key admeasurement is 2040 $.25 [4]. RC6 was advised to accommodated the requirements of the Advanced Encryption Standard (AES)competition. RC6 able has ablock sizeof 128 $.25 and supportskey sizesof 128, 192 and 256 bits, but, like RC5. RC6 can be beheld as interweaving two alongside RC5 encryption processes. It uses an added multiplication operation not present in RC5 in adjustment to accomplish the circling abased on every bit in a word.

SHA-256

SHA-256 operates on eight 32-bit words. The bulletin to be hashed is first

  1. padded with its breadth in such a way that the aftereffect is a assorted of 512 $.25 long, and then
  2. parsed into 512-bit bulletin blocks M(1);M(2); : : :;M(N).

The bulletin blocks are candy one at a time: Beginning with a anchored antecedent assortment bulk H(0), sequentially compute

Where C is the SHA-256 compression action and + agency word-wise mod 264 addition. H(N) is the assortment of M [5].

SHA-512

SHA-512 is a alternative of SHA-256 which operates on eight 64-bit words and block admeasurement of 1024 bits. It uses altered about-face amounts and accretion constants, but its anatomy is contrarily around identical, differing alone in the cardinal of rounds, which are 80 for SHA-512[15].

HASH FUNCTION

A cryptographic assortment action is a algebraic transformation that takes a bulletin of approximate breadth and computes a anchored breadth bulk additionally accepted as assortment value, bulletin digest, assortment code, assortment sum, checksum, etc.

Where H is Assortment Function, M is capricious breadth message; H is anchored admeasurement assortment value. Creating assortment action is able by iteration. Instead of appliance a assortment action with variable-size input, a action with anchored admeasurement ascribe is created and is acclimated a all-important cardinal of times. This anchored admeasurement ascribe action is accepted as compression function. It compresses an n-bit cord to actualize a m-bit cord area n is commonly greater than m. This arrangement is referred to as an common cryptographic assortment action [6]. These compression action abatement into two categories: a action distinctively advised for the assortment action or a symmetric block blank [2].

Figure 2. Common Cryptographic assortment Function

Characteristics of one way Assortment Function:

  1. Given M, it is accessible to compute h.
  2. Given h, it is adamantine to compute M such that.
  3. Given M, it is adamantine to acquisition accession message, M’, such that

The accomplished point of one way assortment action is to accommodate a feel book of M that is unique. In some appliance one wayness is insufficient; we charge an added claim alleged collision-resistance (It is adamantine to acquisition two accidental messages, M and M’, such that [1]).

Figure 3. Basal Assortment Algorithm at sender and receiver

Hash Action takes bulletin and an antecedent bulk as an ascribe and produces the assortment value. The assortment bulk is added to the bulletin at a time back the bulletin is affected or accepted to be correct. The receiver authenticates the bulletin by breeding the assortment bulk with the aforementioned action and compares it with the assortment bulk accelerate by the sender. If both the bulk matches afresh the accustomed bulletin is aforementioned as it is accelerate by the sender contrarily bulletin has been tampered with.

RC6

RC6 [7] is a absolutely parameterized ancestors of encryption algorithms. A adaptation of RC6 is added accurately defined as RC6-w r bwhere the chat admeasurement is wbits, encryption consists of a nonnegative cardinal of roundsr, andbdenotes the breadth of the encryption key in bytes. Since the AES acquiescence is targeted atw= 32 andr= 20, we shall use RC6 as autograph to accredit to such versions. Back any alternative bulk ofworris advised in the text, the constant ethics will be defined as RC6-w r. Of authentic appliance to the AES accomplishment will be the versions of RC6 with 16-, 24-, and 32-byte keys [4].

Figure 4. RC6 Encryption

For all variants, RC6-w r boperates on units of fourw-bit words appliance the afterward six basal operations.

integer accession modulo

integer addition modulo

bitwise exclusive-or of w-bit words

integer multiplication modulo

Rotate to the larboard by the bulk accustomed by the atomic cogent $.25 of

Rotate A to the right, similarly

alongside assignment

Key Expansion

Use two abracadabra constants:-

Where:-

…….(base of accustomed logarithm)

……..()

is the odd accumulation abutting to .

INPUT

byte key that is preloaded into chat arrangement

denotes the no of rounds.

OUTPUT

w-bit annular keys .

ALGORITHM

  1. For do

Encryption

Four w-bit registers A, B, C, D accommodate the antecedent ascribe plain-text as able-bodied as the achievement ciphertext at the end of encryption. The aboriginal byte of plaintext is placed in the atomic cogent byte of A; the aftermost byte of plaintext is placed into the best cogent byte of D [6].

INPUT

Plaintext stored in four w-bit ascribe registers

Number r of circuit w-bit annular keys

OUTPUT

Ciphertext stored in

ALGORITHM

  1. C = C + S[2r + 3]

Decryption

For decryption of cipher-text amount these blank argument into registers A, B, C, D Algorithm uses accumulation addition modulo 2w and appropriate circling on registers for accepting apparent text.

INPUT

Ciphertext stored in four w-bit ascribe registers

Number r of rounds

w-bit annular keys

OUTPUT

Plaintext stored in

ALGORITHM

HASH FUNCTION USING RC6

RC6 is a uses 44 words of key actual authoritative it added circuitous to break. RC6 parameterized cipher; the block admeasurement can be developed in a aboveboard address to 256 $.25 and beyond.RC6 has best key admeasurement of 2040 bits, authoritative the agnate assortment action actual fast.20 circuit appliance RC6 will accept all these appearance which accomplish the assortment added able and secure.

It is accessible to use a symmetric block blank algorithm as a assortment function. If the block algorithm is secure, afresh the one-way assortment action will additionally be secure. One access is to encrypt the bulletin with the algorithm in CBC mode, a anchored key and an antecedent agent (IV), the aftermost blank argument block is the assortment value. Accession added bigger access uses the bulletin block as the key, the antecedent assortment bulk as the output. Actuality we will use additional approach.

Algorithm presented actuality has capricious ambit i.e. altered constant bulk can be taken according to the need. Block admeasurement (b), Cardinal of circuit (r), breadth of assortment bulk (l) are the altered capricious ambit that are the inputs of the algorithm. The breadth of assortment bulk (l) should be assorted of 256.

First of all added is done. Bulletin is bedlam with zeros in a way such that the bedlam bulletin breadth is assorted of the block admeasurement (b).

Then antecedent agent is bare to accomplish the assortment value. Antecedent Agent is a allotment of abstracts is bare to activate active an algorithm, and is not secret. There are two antecedent vectors in this algorithm which are acclimated to accomplish antecedent assortment value.

To accomplish the antecedent assortment bulk aggregate of v (size of assortment bulk disconnected by 256) 256 $.25 ethics affected as follows:

After breeding antecedent assortment bulk from antecedent vectors the bulletin (M) is disconnected into cardinal of baby chunks (n). The admeasurement of bulletin chunks should be according to block admeasurement b, afterwards that RC6 key bearing is activated on anniversary bulletin block to accomplish keys that will be acclimated to encrypt the antecedent assortment bulk to accomplish abutting assortment value. Antecedent 256 $.25 v assortment ethics are encrypted via RC6 appliance RC6 keys generated from aboriginal bulletin block (M1). This is afresh encrypted afresh from the keys generated from additional bulletin block (M2) and so on until all the bulletin blocks (n) are used. At aftermost all the v final assortment ethics of breadth 256 bit anniversary are concatenated to accomplish the final assortment bulk of breadth l.

Number of circuit (r) is disconnected in to two parts, 3r/4 circuit are acclimated to accomplish the RC6 keys from the bulletin block and r/4 circuit are acclimated to encrypt the antecedent assortment bulk to accomplish abutting assortment value. Figure 5 shows the action for assortment bulk of admeasurement 512 bits.

Figure 5. Assortment Bulk Bearing appliance RC6

PSEUDO CODE

INPUT

Message M,

Number of circuit r,

Block admeasurement b,

Length of assortment bulk l;

OUTPUT

Final assortment bulk h;

ALGORITHM

  1. Pad 0s (zeros) at the end of the bulletin so the bulletin breadth is assorted of b;
  2. Divide bulletin into chunks of admeasurement b;
  3. Repeat footfall 7 to 21
  4. Load
  5. Repeat footfall 10 to 12
  6. Repeat footfall 13 to 16
  7. Repeat footfall 20
  8. Repeat footfall 22 to 33
  9. Load
  10. Repeat footfall 26 to 30 for do
  11. Load
  12. Concatenate to get final assortment bulk h

PERFORMANCE AND ANALYSIS

This algorithm was implemented appliance java in NetBeans IDE 7.0.1. Afterward after-effects were acquired on Intel(R) Core(TM) i3 CPU M 370 @ 2.40 GHz 2.39 GHz 32 bit arrangement with 4 GB of RAM active Windows 7 Ultimate.

Algorithm presented in this cardboard is compared with SHA-256 and SHA-512 respectively. Allegory amid algorithm presented actuality and SHA are done on the base of throughput of the algorithms and time to aftermath assortment bulk for files of altered sizes. To be added authentic the affairs is accomplished ten times for anniversary ascribe book and the boilerplate of those after-effects are appear here.

Results in Figure 6 to Figure 9 and Table 1 for Assortment appliance RC6 are acquired for r=64, b=512, l=256 and these after-effects are compared with SHA-256 which has aforementioned bulk for these parameters.

Figure 6. Throughput of RC6_HASH and SHA-256.

Figure 7. Bar Blueprint of Assortment bulk bearing time of RC6_HASH and SHA-512

Figure 8. Line Blueprint of Assortment bearing time of HASH_RC6 (256) and SHA-256

Figure 9. Beheading time extenuative acquired by Hash_RC6

File Name

File Admeasurement (Kb)

Hash_RC6

SHA-256

A.html

94

261.4

365.4

B.ppt

567

1671

3757.2

C.txt

244

513.57

827.3

D.jpg

827

2626.1

5992.1

E.flv

7107

23308.6

45203.2

F.mp3

8218

26195.9

32090.8

G.doc

255

757.2

1319.2

H.pdf

229

640.9

1278.8

I.png

217

641.8

1283.7

J.wmv

25631

84558.5

110003

Table 1. Allegory of Hash_RC6 (256) & SHA-256 on the base of Beheading Time of altered blazon of Files.

Figure 6 shows the throughput of RC6_HASH and SHA-256 the algorithms in KB/sec. Figure 7 shows the Bar Blueprint assortment bulk bearing time (in millisec) of both the algorithms for the book of altered sizes (in KB).

Figure 8 shows the Line-Graph of beheading time according to their book admeasurement for anniversary book appliance algorithms Hash_RC6 (256) and SHA-256. Line blueprint is added acceptable to appearance that Hash_RC6 (256) performs faster than SHA-256. This Blueprint additionally shows that for the book of baby admeasurement both the algorithms performs about aforementioned i.e. there is not abundant of the aberration but back the book admeasurement increases Hash_RC6 (256) performs abundant bigger than the SHA-256.

Bar blueprint in Figure 9 shows the beheading time extenuative acquired by Hash_RC6 in allotment in allegory with SHA-256 for altered book sizes. It’s greater than 30% for about all the book sizes and for some of the book sizes its approx 50% that is greater advancement. The boilerplate percent beheading time extenuative by Hash_RC6 for assortment bulk of 256 $.25 over SHA-256 is 40.26.

We analyze the beheading time of anniversary algorithm on altered book types like argument file, audio book & video files, for this purpose we mainly acclimated 10 files and recorded their assortment bulk bearing time in milliseconds for these algorithms. List of Ascribe files and their admeasurement are accustomed in Table 1.

Results in Figure 10 to Figure 13 and Table 2 for Assortment appliance RC6 are acquired for r=80,b=1024,l=512 and these after-effects are compared with SHA-512 which has aforementioned bulk for these parameters.

Figure 10. Throughput of RC6_HASH and SHA-512.

Figure 11. Bar Blueprint of Assortment bulk bearing time of RC6_HASH and SHA-512

Figure 12. Line Blueprint of Assortment Bearing Time of HASH_RC6 (512) and SHA-512

Figure 13. Beheading Time extenuative acquired by Hash_RC6

File Name

File Admeasurement (Kb)

Hash_RC6 (512)

SHA-512

A.html

94

240.1

278.9

B.ppt

567

1577.3

2736.6

C.txt

244

694.7

932.4

D.jpg

827

2192.8

4075.6

E.flv

7107

20341.2

29664.1

F.mp3

8218

22848.5

33323.4

G.doc

255

598.3

1224.7

H.pdf

229

480.1

1054.6

I.png

217

546.1

705.2

J.wmv

25631

78942.4

95852.9

Table 2. Allegory of Hash_RC6 (512) & SHA-512 on the base of Beheading Time of altered blazon of Files.

Figure 10 shows the throughput of RC6_HASH and SHA-512 the algorithms in KB/sec. Figure 11 shows the Bar Blueprint of assortment bulk bearing time (in millisec) of both the algorithms for the book of altered sizes (in KB).

Figure 12 shows the Line-Graph of beheading time according to their book admeasurement for anniversary book appliance algorithms Hash_RC6 (512) and SHA-512. Line blueprint is added acceptable to appearance that Hash_RC6 (512) performs faster than SHA-512. This Blueprint additionally shows that the aberration is not so abundant for book of baby admeasurement but back it comes to book of beyond admeasurement Hash_RC6 (512) is abundant bigger than the SHA-512.

Bar blueprint in Figure 13 shows the beheading time extenuative acquired by Hash_RC6 (512) in allotment in allegory with SHA-512 for altered book sizes. It’s greater than 15% for about all the book sizes and for some of the book sizes its approx 35% that is greater advancement. The boilerplate percent beheading time extenuative by Hash_RC6 for assortment bulk of 512 $.25 over SHA-512 is 24.625.

We analyze the beheading time of anniversary algorithm on altered book types like argument file, audio book & video files, for this purpose we mainly acclimated 10 files and recorded their assortment bulk bearing time in milliseconds for these algorithms. List of Ascribe files and their admeasurement are accustomed in Table 2.

CONCLUSION

In this analysis cardboard a new algorithm for breeding assortment bulk is presented. This algorithm is generated on a symmetric block blank accepted as RC6 and can accomplish assortment bulk of altered sizes. The algorithm can additionally accomplish on altered block admeasurement and altered cardinal of rounds. The accomplishing of algorithm is done appliance JAVA in NetBeans IDE 7.0.1. on Intel(R) Core(TM) i3 CPU M 370 @ 2.40 GHz 2.39 GHz 32 bit arrangement with 4 GB of RAM active Windows 7 Ultimate.

Hash bulk generated appliance algorithm presented actuality are defended adjoin abounding advance because back a assortment algorithm is generated appliance symmetric block blank it accede the backdrop of basal cipher. The abstraction abaft this is that if the symmetric block algorithm is defended afresh the generated assortment action will additionally be defended [1].

Then the algorithm is compared with SHA-256 and SHA-512 for aforementioned constant and on the aforementioned environment. The after-effects of allegory achieve that the algorithm present actuality has bigger throughput

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