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Wired Equivalent Privacy (WEP): The first ‘confidentiality’ algorithm

Wired Equivalent Privacy (WEP): The first ‘confidentiality’ algorithm for the wireless IEEE 802.11 standard. PRESENTED BY: Samuel Grush and Barry Preston. Packet. Initialization Vector (IV). IV. ciphertext. XOR. Seed. Secret Key. plaintext. ICV. CRC-32. WEP Components.

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Wired Equivalent Privacy (WEP): The first ‘confidentiality’ algorithm

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  1. Wired Equivalent Privacy (WEP): The first ‘confidentiality’ algorithm for the wireless IEEE 802.11 standard. PRESENTED BY: Samuel Grush and Barry Preston

  2. Packet Initialization Vector (IV) IV ciphertext XOR Seed Secret Key plaintext ICV CRC-32 WEP Components • Secret Key and Plaintext • Initialization Vector (IV) • RC4 Stream Cipher • Key Scheduling Algorithm (KSA) • Seeded by IV+Secret Key • Passes 'State' Array to PRGA • Pseudo-Random Generation Algorithm (PRGA) • Uses 'State' Array to generate a keystream, while also mixing the Array. • Plaintext is combined with its checksum. • Bitwise-XOR • • [when encrypting]Plaintext is bitwise-XOR'd with keystream data to generate cyphertext. KSA PRGA

  3. Packet Seed KSA PRGA IV Received ICV ciphertext XOR plaintext ≟ WEP Decryption Secret Key CRC-32

  4. Key Scheduling Algorithm

  5. Pseudo-Random Generation Algorithm

  6. Weaknesses • The Initialization Vector (IV) 24-bit length limits the IV's entropy to 2²⁴, or about 16.7 million combinations. • Certain characters in the 802.11 header are known or can be predicted, leading to a lessened effective entropy. • The 'Shared Key' authentication system of WEP exposes the beginning of the keystream.

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