SSL Security Essay Example | Topics and Well Written Essays - 750 words

SSL Security - Essay Example SSL implementations provide various secret and public key encryption algorithms. The secret algorithm keys employ key lengths spanning from 40 to 168 bits. Most SSL software is limited to 521 bit RSA keys and 40 bit secret keys given export restrictions (Bossley). Brute force searches are a technique that exhaustively tries out possible keys until an appropriate one is found. In a bid to identify an appropriate key, it is required that one be in possession of a plaintext and the corresponding ciphertext (Eugene, 2). Advancements in technology resulting in enhanced computing performance have increasingly made practical exhaustive key searches against keys that are of fixed length. The dictionary attack is the most effective type of known plaintext attacks especially when a reduced number of crypto keys are used. Attackers thereby develop a dictionary comprising all possible encryptions of known plaintext messages such as the Get command. On receiving the encrypted message, the dictionary looks it up. An attack occurs when the ciphertext matches a particular entry in the dictionary that was previously encrypted using an identical secret key (Giacomo 1). SSL prevents dictionary attacks by using the 128 bit keys wherein 40 bits are kept secret while the rest are derived from the data revealed in hello messages. The combination of both the 40 bit secret key and the 88 bit known key results in an encryption that employs all 128 bits. This renders dictionary attacks impossible given that they also should have differentiated entries in order to realize all 128 bit keys. SSL prevents replay attacks during handshaking protocols through the use of a 128bit nonce which is unique to a given connection. The nonce is unpredictable in advance given that it is based on events that are also unpredictable (Bossley). The attacker gathers messages earlier transmitted and replays them in a bid to repeat interesting transactions such as the transfer of money. In this