Acrónimos: OFB
Ver:
· [NIST-SP800-38A:2001]
· [FIPS-81:1980]
· Criptografía de clave secreta
· http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
Modalidad de
cifrado de flujo cuyo generador de la serie cifrante está constituido por un
cifrado de bloques seguido por un selector de bits. [Ribagorda:1997]
(N) A block
cipher mode that modifies ECB mode to operate on plaintext segments of variable
length less than or equal to the block length. [FP081] (See: block cipher, [SP38A].)
[RFC4949:2007]
The output
feedback (OFB) mode makes a block cipher into a synchronous stream cipher: it
generates keystream blocks, which are then XORed with the plaintext blocks to
get the ciphertext. Just as with other stream ciphers, flipping a bit in the
ciphertext produces a flipped bit in the plaintext at the same location. This
property allows many error correcting codes to function normally even when
applied before encryption.
Because of the
symmetry of the XOR operation, encryption and decryption are exactly the same.
http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
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