BitLocker: Difference between revisions
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== AES-CBC == |
== AES-CBC == |
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The AES is a widely used symmetric block cipher that works on fixed blocks, the block size is always a multiple of 16 bytes so no padding is necessary. BitLocker provides AES key size of either 128 Bits or 256 bits depending on the users choosing. |
The AES is a widely used symmetric block cipher that works on fixed blocks, the block size is always a multiple of 16 bytes so no padding is necessary. BitLocker provides AES key size of either 128 Bits or 256 bits depending on the users choosing. |
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CBC – Cipher-Block chaining mode was invented by IBM in 1976, each block of plaintext is XORed with the previous ciphertext block before beeing encrypted, where the IV(initiation vector) under BitLocker is selected through a function that maps each sector number into a unique 16-byte value. This way, each ciphertext block depends on the previous blocks which have been proccesed, so if any changes are made to a cipherblock every following block of plaintext is effected. |
CBC – Cipher-Block chaining mode was invented by IBM in 1976, each block of plaintext is XORed with the previous ciphertext block before beeing encrypted, where the IV(initiation vector) under BitLocker is selected through a function that maps each sector number into a unique 16-byte value. This way, each ciphertext block depends on the previous blocks which have been proccesed, so if any changes are made to a cipherblock every following block of plaintext is effected. |
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Revision as of 13:24, 23 May 2008
BitLocker
Bitlocker Drive Encryption is a data protection feature integrated in Windows Vista Ultimate and Windows Vista Enterprise, which was designed to protect the data through encrypting the entire system volume. For the encryption the Advanced Encryption Standard (AES) algorithm in Cipher-block chaining is used, as well as the Elephant-Diffuser which provides more security that is not provided through AES alone. Further more Bitlocker, on computers with a compatible Trusted Platform Module (TPM), provides a way to validate the integrity of the startup components of the system before starting vista itself.
AES-CBC
The AES is a widely used symmetric block cipher that works on fixed blocks, the block size is always a multiple of 16 bytes so no padding is necessary. BitLocker provides AES key size of either 128 Bits or 256 bits depending on the users choosing.
CBC – Cipher-Block chaining mode was invented by IBM in 1976, each block of plaintext is XORed with the previous ciphertext block before beeing encrypted, where the IV(initiation vector) under BitLocker is selected through a function that maps each sector number into a unique 16-byte value. This way, each ciphertext block depends on the previous blocks which have been proccesed, so if any changes are made to a cipherblock every following block of plaintext is effected.
(work in progress)