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Diffstat (limited to 'secure/lib/libcrypto/man/des_modes.3')
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diff --git a/secure/lib/libcrypto/man/des_modes.3 b/secure/lib/libcrypto/man/des_modes.3 deleted file mode 100644 index 788e0e8..0000000 --- a/secure/lib/libcrypto/man/des_modes.3 +++ /dev/null @@ -1,290 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Mon Jan 13 19:29:14 2003 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" 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. | will give a -.\" real vertical bar. \*(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-|\(bv\*(Tr -.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' -.ie n \{\ -. 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\} -.el\{\ -. ds -- \|\(em\| -. ds PI \(*p -. ds L" `` -. ds R" '' -'br\} -.\" -.\" If the F register is turned on, we'll generate index entries on stderr -.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and -.\" index entries marked with X<> in POD. Of course, you'll have to process -.\" the output yourself in some meaningful fashion. -.if \nF \{\ -. de IX -. tm Index:\\$1\t\\n%\t"\\$2" -.. -. nr % 0 -. rr F -.\} -.\" -.\" For nroff, turn off justification. Always turn off hyphenation; it -.\" makes way too many mistakes in technical documents. -.hy 0 -.if n .na -.\" -.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). -.\" Fear. Run. Save yourself. No user-serviceable parts. -.bd B 3 -. \" fudge factors for nroff and troff -.if n \{\ -. ds #H 0 -. ds #V .8m -. ds #F .3m -. ds #[ \f1 -. ds #] \fP -.\} -.if t \{\ -. ds #H ((1u-(\\\\n(.fu%2u))*.13m) -. ds #V .6m -. ds #F 0 -. ds #[ \& -. ds #] \& -.\} -. \" simple accents for nroff and troff -.if n \{\ -. ds ' \& -. ds ` \& -. ds ^ \& -. ds , \& -. ds ~ ~ -. ds / -.\} -.if t \{\ -. 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 -.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' -.ds 8 \h'\*(#H'\(*b\h'-\*(#H' -.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] -.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' -.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' -.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] -.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] -.ds ae a\h'-(\w'a'u*4/10)'e -.ds Ae A\h'-(\w'A'u*4/10)'E -. \" corrections for vroff -.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' -.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' -. \" for low resolution devices (crt and lpr) -.if \n(.H>23 .if \n(.V>19 \ -\{\ -. 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 -.\} -.rm #[ #] #H #V #F C -.\" ====================================================================== -.\" -.IX Title "des_modes 3" -.TH des_modes 3 "0.9.7" "2003-01-13" "OpenSSL" -.UC -.SH "NAME" -Modes of \s-1DES\s0 \- the variants of \s-1DES\s0 and other crypto algorithms of OpenSSL -.SH "DESCRIPTION" -.IX Header "DESCRIPTION" -Several crypto algorithms for OpenSSL can be used in a number of modes. Those -are used for using block ciphers in a way similar to stream ciphers, among -other things. -.SH "OVERVIEW" -.IX Header "OVERVIEW" -.Sh "Electronic Codebook Mode (\s-1ECB\s0)" -.IX Subsection "Electronic Codebook Mode (ECB)" -Normally, this is found as the function \fIalgorithm\fR\fI_ecb_encrypt()\fR. -.Ip "\(bu" 2 -64 bits are enciphered at a time. -.Ip "\(bu" 2 -The order of the blocks can be rearranged without detection. -.Ip "\(bu" 2 -The same plaintext block always produces the same ciphertext block -(for the same key) making it vulnerable to a 'dictionary attack'. -.Ip "\(bu" 2 -An error will only affect one ciphertext block. -.Sh "Cipher Block Chaining Mode (\s-1CBC\s0)" -.IX Subsection "Cipher Block Chaining Mode (CBC)" -Normally, this is found as the function \fIalgorithm\fR\fI_cbc_encrypt()\fR. -Be aware that \fIdes_cbc_encrypt()\fR is not really \s-1DES\s0 \s-1CBC\s0 (it does -not update the \s-1IV\s0); use \fIdes_ncbc_encrypt()\fR instead. -.Ip "\(bu" 2 -a multiple of 64 bits are enciphered at a time. -.Ip "\(bu" 2 -The \s-1CBC\s0 mode produces the same ciphertext whenever the same -plaintext is encrypted using the same key and starting variable. -.Ip "\(bu" 2 -The chaining operation makes the ciphertext blocks dependent on the -current and all preceding plaintext blocks and therefore blocks can not -be rearranged. -.Ip "\(bu" 2 -The use of different starting variables prevents the same plaintext -enciphering to the same ciphertext. -.Ip "\(bu" 2 -An error will affect the current and the following ciphertext blocks. -.Sh "Cipher Feedback Mode (\s-1CFB\s0)" -.IX Subsection "Cipher Feedback Mode (CFB)" -Normally, this is found as the function \fIalgorithm\fR\fI_cfb_encrypt()\fR. -.Ip "\(bu" 2 -a number of bits (j) <= 64 are enciphered at a time. -.Ip "\(bu" 2 -The \s-1CFB\s0 mode produces the same ciphertext whenever the same -plaintext is encrypted using the same key and starting variable. -.Ip "\(bu" 2 -The chaining operation makes the ciphertext variables dependent on the -current and all preceding variables and therefore j-bit variables are -chained together and can not be rearranged. -.Ip "\(bu" 2 -The use of different starting variables prevents the same plaintext -enciphering to the same ciphertext. -.Ip "\(bu" 2 -The strength of the \s-1CFB\s0 mode depends on the size of k (maximal if -j == k). In my implementation this is always the case. -.Ip "\(bu" 2 -Selection of a small value for j will require more cycles through -the encipherment algorithm per unit of plaintext and thus cause -greater processing overheads. -.Ip "\(bu" 2 -Only multiples of j bits can be enciphered. -.Ip "\(bu" 2 -An error will affect the current and the following ciphertext variables. -.Sh "Output Feedback Mode (\s-1OFB\s0)" -.IX Subsection "Output Feedback Mode (OFB)" -Normally, this is found as the function \fIalgorithm\fR\fI_ofb_encrypt()\fR. -.Ip "\(bu" 2 -a number of bits (j) <= 64 are enciphered at a time. -.Ip "\(bu" 2 -The \s-1OFB\s0 mode produces the same ciphertext whenever the same -plaintext enciphered using the same key and starting variable. More -over, in the \s-1OFB\s0 mode the same key stream is produced when the same -key and start variable are used. Consequently, for security reasons -a specific start variable should be used only once for a given key. -.Ip "\(bu" 2 -The absence of chaining makes the \s-1OFB\s0 more vulnerable to specific attacks. -.Ip "\(bu" 2 -The use of different start variables values prevents the same -plaintext enciphering to the same ciphertext, by producing different -key streams. -.Ip "\(bu" 2 -Selection of a small value for j will require more cycles through -the encipherment algorithm per unit of plaintext and thus cause -greater processing overheads. -.Ip "\(bu" 2 -Only multiples of j bits can be enciphered. -.Ip "\(bu" 2 -\&\s-1OFB\s0 mode of operation does not extend ciphertext errors in the -resultant plaintext output. Every bit error in the ciphertext causes -only one bit to be in error in the deciphered plaintext. -.Ip "\(bu" 2 -\&\s-1OFB\s0 mode is not self-synchronizing. If the two operation of -encipherment and decipherment get out of synchronism, the system needs -to be re-initialized. -.Ip "\(bu" 2 -Each re-initialization should use a value of the start variable -different from the start variable values used before with the same -key. The reason for this is that an identical bit stream would be -produced each time from the same parameters. This would be -susceptible to a 'known plaintext' attack. -.Sh "Triple \s-1ECB\s0 Mode" -.IX Subsection "Triple ECB Mode" -Normally, this is found as the function \fIalgorithm\fR\fI_ecb3_encrypt()\fR. -.Ip "\(bu" 2 -Encrypt with key1, decrypt with key2 and encrypt with key3 again. -.Ip "\(bu" 2 -As for \s-1ECB\s0 encryption but increases the key length to 168 bits. -There are theoretic attacks that can be used that make the effective -key length 112 bits, but this attack also requires 2^56 blocks of -memory, not very likely, even for the \s-1NSA\s0. -.Ip "\(bu" 2 -If both keys are the same it is equivalent to encrypting once with -just one key. -.Ip "\(bu" 2 -If the first and last key are the same, the key length is 112 bits. -There are attacks that could reduce the effective key strength -to only slightly more than 56 bits, but these require a lot of memory. -.Ip "\(bu" 2 -If all 3 keys are the same, this is effectively the same as normal -ecb mode. -.Sh "Triple \s-1CBC\s0 Mode" -.IX Subsection "Triple CBC Mode" -Normally, this is found as the function \fIalgorithm\fR\fI_ede3_cbc_encrypt()\fR. -.Ip "\(bu" 2 -Encrypt with key1, decrypt with key2 and then encrypt with key3. -.Ip "\(bu" 2 -As for \s-1CBC\s0 encryption but increases the key length to 168 bits with -the same restrictions as for triple ecb mode. -.SH "NOTES" -.IX Header "NOTES" -This text was been written in large parts by Eric Young in his original -documentation for SSLeay, the predecessor of OpenSSL. In turn, he attributed -it to: -.PP -.Vb 5 -\& AS 2805.5.2 -\& Australian Standard -\& Electronic funds transfer - Requirements for interfaces, -\& Part 5.2: Modes of operation for an n-bit block cipher algorithm -\& Appendix A -.Ve -.SH "SEE ALSO" -.IX Header "SEE ALSO" -blowfish(3), des(3), idea(3), -rc2(3) |
