Output Feedback Mode (OFB) is an encryption mode, that builds a synchronous stream-cipher from a block-cipher.

Output Feedback Mode (OFB) makes a block-cipher into a stream cipher by generating a keystream using the block-cipher that is XORed with the plaintext to produce the ciphertext. OFB mode feeds back the raw output of the block-cipher as the next input of the block-cipher to create successive keystream blocks.

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