Standard preamble:
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..
.... Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.
If the F register is turned on, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.
Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================
Title "blowfish 3"
way too many mistakes in technical documents.
Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. It uses a variable size key, but typically, 128 bit (16 byte) keys are considered good for strong encryption. Blowfish can be used in the same modes as \s-1DES \s0(see des_modes\|(7)). Blowfish is currently one of the faster block ciphers. It is quite a bit faster than \s-1DES,\s0 and much faster than \s-1IDEA\s0 or \s-1RC2.\s0
Blowfish consists of a key setup phase and the actual encryption or decryption phase.
\fIBF_set_key() sets up the \s-1BF_KEY\s0 key using the len bytes long key at data.
\fIBF_ecb_encrypt() is the basic Blowfish encryption and decryption function. It encrypts or decrypts the first 64 bits of in using the key key, putting the result in out. enc decides if encryption (\s-1BF_ENCRYPT\s0) or decryption (\s-1BF_DECRYPT\s0) shall be performed. The vector pointed at by \fBin and out must be 64 bits in length, no less. If they are larger, everything after the first 64 bits is ignored.
The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and BF_ofb64_encrypt() all operate on variable length data. They all take an initialization vector \fBivec which needs to be passed along into the next call of the same function for the same message. ivec may be initialized with anything, but the recipient needs to know what it was initialized with, or it won't be able to decrypt. Some programs and protocols simplify this, like \s-1SSH,\s0 where \fBivec is simply initialized to zero. \fIBF_cbc_encrypt() operates on data that is a multiple of 8 bytes long, while \fIBF_cfb64_encrypt() and BF_ofb64_encrypt() are used to encrypt an variable number of bytes (the amount does not have to be an exact multiple of 8). The purpose of the latter two is to simulate stream ciphers, and therefore, they need the parameter num, which is a pointer to an integer where the current offset in ivec is stored between calls. This integer must be initialized to zero when ivec is initialized.
\fIBF_cbc_encrypt() is the Cipher Block Chaining function for Blowfish. It encrypts or decrypts the 64 bits chunks of in using the key schedule, putting the result in out. enc decides if encryption (\s-1BF_ENCRYPT\s0) or decryption (\s-1BF_DECRYPT\s0) shall be performed. ivec must point at an 8 byte long initialization vector.
\fIBF_cfb64_encrypt() is the \s-1CFB\s0 mode for Blowfish with 64 bit feedback. It encrypts or decrypts the bytes in in using the key schedule, putting the result in out. enc decides if encryption (\s-1BF_ENCRYPT\s0) or decryption (\s-1BF_DECRYPT\s0) shall be performed. ivec must point at an 8 byte long initialization vector. num must point at an integer which must be initially zero.
\fIBF_ofb64_encrypt() is the \s-1OFB\s0 mode for Blowfish with 64 bit feedback. It uses the same parameters as BF_cfb64_encrypt(), which must be initialized the same way.
\fIBF_encrypt() and BF_decrypt() are the lowest level functions for Blowfish encryption. They encrypt/decrypt the first 64 bits of the vector pointed by \fBdata, using the key key. These functions should not be used unless you implement 'modes' of Blowfish. The alternative is to use BF_ecb_encrypt(). If you still want to use these functions, you should be aware that they take each 32-bit chunk in host-byte order, which is little-endian on little-endian platforms and big-endian on big-endian ones.