Performance of RC4 Security Algorithm on ARM ProcessorAnil kumar. B Guide: Assoc .prof. K.Raghuram M.Tech

Aim of the Projecty To develop a RC4 security Algorithm for WLAN WEP

protocol using ARM processor y To provide a enhanced level of security using RC4 algorithm and introducing a variation in key length y Also by implementing Elgemal

Speed comparisons: (from Crypto++ 5.1 benchmarks, on a 2.1 GHz P4):Algorithm Speed (MByte/s.) DES 22 AES 62 RC5-32/12 79 RC4 111 SEAL 920 MD5 205

Key lengths of different algorithmsAlgorithm Name Key Length (bits) Blowfish Up to 448 DES 56 IDEA 128 RC2 RC2 Up to 2048 RC4 RC4 Up to 2048 RC5 RC5 Up to 2048 Triple DES 192

Attacker Computer Resources Keys / Second Individual attacker One high-performance desktop machine & Software high2^17 2^24 Small group 16 high-end machines & Software high2^21 2^24 Academic Network 256 high-end machines & Software high2^25 2^28 Large company $1,000,000 hardware budget 000, 2^43 Military Intelligence agency $1,000,000 hardware budget + advanced technology 000, 2^55

Encryption Classificationy Strong encryption y Encryption methods that cannot be cracked by brute-force (in a reasonable period of time). y The world fastest computer needs thousands of years to compute a key. y Weak encryption y A code that can be broken in a practical time frame. y 56-bit encryption was cracked in 1999. y 64-bit will be cracked in 2011. y 128-bit will be cracked in 2107.

An Introduction to Cryptography

The encryption model (for a symmetric-key cipher)

Stream Cipher Mode

A stream cipher. (a) Encryption. (b)Decryption.

Encryption Basicsy Encryption is yet another process by which information is

protected from unauthorized access. y It is normally accomplished by rendering the original information unreadable by using a reversible technique known only to the authorized entities.

Types of Encryptiony Private/Symmetric Key Cryptography :

Same key is used for encryption and decryption.y Public/Asymmetric Key Cryptography :

Different keys are used for encryption and decryption.

RC4 Basicsy A symmetric key encryption algo. Invented by Ron Rivest. y Normally uses 64 bit and 128 bit key sizes. y Most popular implementation is in WEP for 802.11 wireless

networks and in SSL. y Cryptographically very strong yet very easy to implement. y Consists of 2 parts: Key Scheduling Algorithm (KSA) & Pseudo-Random Generation Algorithm

RC4 break upy Initialize an array of 256 bytes. y Run the KSA on them y Run the PRGA on the KSA output to generate keystream. y XOR the data with the keystream.

Array InitializationC Code: char S[256]; Int i; For(i=0; i< 256; i++) S[i] = i; After this the array would like this : S[] = { 0,1,2,3, , 254, 255}

The KSAy The initialized array S[256] is now run through the KSA. The

KSA uses the secret key to scramble the array. y C Code for KSA: int i, j = 0; for(i=0; i