问题
I can't find it anywhere, when I google it it shows this question posted here. Given that situation I want to ask precisely: What this "n" before cfb and ofb means ?
回答1:
This is one reference to nCFB and nOFB that I could find:
Note that CFB and OFB in the rest of the document represent the "8bit CFB or OFB" mode. nOFB and nCFB modes represents a n-bit OFB/CFB mode, n is used to represent the algorithm's block size.
...
nOFB: The Output-Feedback Mode (in nbit). n Is the size of the block of the algorithm. This is a synchronous stream cipher implemented from a block cipher. It is intended for use in noisy lines, because corrupted ciphertext blocks do not corrupt the plaintext blocks that follow. This mode operates in streams.
nCFB: The Cipher-Feedback Mode (in nbit). n Is the size of the block of the algorithm. This is a self synchronizing stream cipher implemented from a block cipher. This mode operates in streams.
http://mcrypt.hellug.gr/lib/mcrypt.3.html
来源：https://stackoverflow.com/questions/4574245/what-are-ncfb-and-nofb-modes-for