bdes.ps

早期freebsd实现

(6e) 198 324 T
(57) 225 324 T
(9c) 252 324 T
(8f) 279 324 T
(27) 306 324 T
(5d) 333 324 T
0 F
-0.31 (Finally) 108 304 P
-0.31 (, if the length of the message is indeed a multiple of the block size, an extra block of) 141.21 304 P
0.83 (all 0 bits is added. Suppose ) 72 284 P
7 F
1.99 (inputf) 210.57 284 P
1.99 (ile) 253.74 284 P
0 F
0.83 ( contains \322) 275.33 284 P
6 F
1.99 (test) 328.28 284 P
9 F
0.83 (\277) 357.07 284 P
0 F
0.83 (\323, and it is encrypted in 40-bit CFB) 364.96 284 P
1.51 (mode using the key \322) 72 264 P
6 F
3.62 (abcdef#@) 179.96 264 P
0 F
1.51 (\323 and the initialization vector ) 237.53 264 P
6 F
3.62 (0x0123456789abcdef) 387.97 264 P
0 F
1.51 (; the) 517.5 264 P
(command is) 72 244 T
6 F
-0.99 (bdes -f40 -v0x0123456789abcdef -kabcdef#@ < ) 72 220 P
7 F
-0.99 (inputf) 383.67 220 P
-0.99 (ile) 426.85 220 P
6 F
-0.99 ( > ) 448.43 220 P
7 F
-0.99 (outputf) 468.04 220 P
-0.99 (ile) 518.41 220 P
0 F
0.16 (because the option ) 72 196 P
4 F
0.16 (\320f40 ) 164.75 196 P
0 F
0.16 (signi\336es 40-bit CFB mode, and ) 189.89 196 P
4 F
0.16 (-v0x01234566789abcdef) 343.96 196 P
0 F
0.16 ( sets the initial-) 465.89 196 P
(ization vector \050note that spaces between the option and its ar) 72 176 T
(gument are optional\051:) 361.57 176 T
(text) 72 152 T
6 F
(t) 144 152 T
(e) 171 152 T
(s) 198 152 T
(t) 225 152 T
9 F
(\277) 252 152 T
0 F
(hex) 72 132 T
10 F
(74) 144 132 T
(65) 171 132 T
(73) 198 132 T
(74) 225 132 T
(0a) 252 132 T
0 F
(input) 72 112 T
10 F
(74) 144 112 T
(65) 171 112 T
(73) 198 112 T
(74) 225 112 T
(0a) 252 112 T
[phone] T
[phone] T
[phone] T
[phone] T
[phone] T
0 F
(output) 72 92 T
10 F
(e2) 144 92 T
(c2) 171 92 T
(69) 198 92 T
(a4) 225 92 T
(5b) 252 92 T
(3c) 279 92 T
(3d) 306 92 T
(b3) 333 92 T
(f5) 360 92 T
(3c) 387 92 T
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(Note here the block size is 40 bits \0505 bytes\051, not 64 bits \0508 bytes\051.) 108 712 T
-0.4 (This technique allows complete compatibility with Sun\325) 108 688 P
-0.4 (s ) 374.11 688 P
3 F
-0.4 (des) 381.37 688 P
0 F
-0.4 ( program. In Sun\325) 397.36 688 P
-0.4 (s implemen-) 480.77 688 P
0.02 (tation, padding is done with random bytes rather than bytes containing all zero bits. Cryptograph-) 72 668 P
0.85 (ically) 72 648 P
0.85 (, this makes no dif) 97.87 648 P
0.85 (ference, as the DES is a suf) 189.32 648 P
0.85 (\336ciently good random cipher to obscure the) 325.74 648 P
(input \050see for example [2], Chapter 6\051, and known plaintext attacks are very dif) 72 628 T
(\336cult [1].) 451.82 628 T
4 F
(5. Differ) 72 596 T
(ences Between the Standard CFB and OFB Modes and ) 114.41 596 T
1 F
(bdes) 397.26 596 T
0 F
-0.11 (The UNIX operating system treats all \336les as streams of 8-bit bytes. In order to implement) 108 572 P
-0.08 (the CFB and OFB modes properly) 72 552 P
-0.08 (, it would be necessary to read ) 235.74 552 P
3 F
-0.08 (k) 383.74 552 P
0 F
-0.08 ( bits from the \336le, where ) 389.07 552 P
3 F
-0.08 (k) 509.51 552 P
0 F
-0.08 ( is an) 514.84 552 P
0.98 (integer between 1 and 64 inclusive. However) 72 532 P
0.98 (, this would require considerable buf) 294.22 532 P
0.98 (fering and be) 474.77 532 P
0.23 (quite inef) 72 512 P
0.23 (\336cient and prohibitively slow) 117.65 512 P
0.23 (. For these reasons, the current implementation of ) 258.48 512 P
3 F
0.23 (bdes) 501.48 512 P
0 F
0.23 ( re-) 523.46 512 P
0.47 (quires that ) 72 492 P
3 F
0.47 (k) 126.23 492 P
0 F
0.47 ( be a multiple of 8, so that an integral number of bytes will always be read from the) 131.56 492 P
(\336le. Other than this change, this mode is implemented as described in [3].) 72 472 T
-0.58 (A similar observation holds for the alternate CFB mode described in [3]. Here, only the low) 108 448 P
0.23 (7 bits of each byte are signi\336cant, and hence the parameter ) 72 428 P
3 F
0.23 (k) 358.95 428 P
0 F
0.23 ( is an integer from 1 to 56 inclusive;) 364.28 428 P
(bdes requires k to be a multiple of 7. The high-order bit is retained for encryption and decryption,) 72 408 T
(but output \050whether from encryption or decryption\051 always has the high-order bit set to zero.) 72 388 T
4 F
(6. Message Authentication Code Modes) 72 356 T
0 F
0.57 (The Data Encryption Standard provides two modes of authentication, each providing be-) 108 332 P
1.27 (tween 1 and 64 bits of authentication data. In both cases an ) 72 312 P
3 F
1.27 (n) 373.32 312 P
0 F
1.27 (-bit message authentication code) 379.32 312 P
0.62 (\050MAC\051 is generated, where 1) 72 292 P
2 F
0.73 ( ) 214.71 292 P
9 F
0.62 (\243) 218.94 292 P
0 F
0.62 ( ) 225.52 292 P
3 F
0.62 (n) 229.15 292 P
0 F
0.62 ( ) 235.14 292 P
9 F
0.62 (\243) 238.76 292 P
0 F
0.62 ( 64. The \336rst is based on the CBC encryption mode, and the) 245.35 292 P
(second on CFB mode. Both work the same.) 72 272 T
0.13 (First, the \336le is padded to a multiple of the block size by appending enough zero bits. It is) 108 248 P
-0.16 (then encrypted using the standard CBC \050or CFB\051 algorithm, but
all encrypted text is discarded ex-) 72 228 P
-0.44 (cept for the last block. The ) 72 208 P
3 F
-0.44 (n) 200.9 208 P
0 F
-0.44 ( leading bits of the last block are used as the MAC. Note that the block) 206.9 208 P
(size constrains the number of bits available as the MAC.) 72 188 T
0.71 (The implementation allows the user to specify that the MAC is to be computed in either) 108 164 P
-0.01 (CBC or CFB mode, and the user can specify any number of bits from 1 to 64 inclusive. However) 72 144 P
-0.01 (,) 537 144 P
-0.11 (because the UNIX operating system can only output bits in multiples of 8, if the number of bits of) 72 124 P
-0.08 (MAC is not a multiple of 8, the MAC will be right-padded with the minimum number of zero bits) 72 104 P
-0.31 (necessary to make the MAC length be a multiple of 8. However) 72 84 P
-0.31 (, note that as the standard \050[3], Ap-) 374.6 84 P
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-0.14 (pendix F\051 requires an incomplete \336nal block be right-padded with
zeroes, the technique of forcing) 72 712 P
(the last octet to contain the number of bytes in the message is ) 72 692 T
3 F
(not) 369.47 692 T
0 F
( used here.) 384.8 692 T
-0.39 (For example, suppose ) 108 668 P
7 F
-0.94 (inputf) 214.76 668 P
-0.94 (ile) 257.93 668 P
0 F
-0.39 ( contains \322) 279.52 668 P
6 F
-0.94 (This) 330.04 668 P
8 F
-0.43 (z) 358.82 668 P
6 F
-0.94 (is) 363.8 668 P
8 F
-0.43 (z) 378.19 668 P
6 F
-0.94 (a) 383.17 668 P
8 F
-0.43 (z) 390.36 668 P
6 F
-0.94 (test) 395.34 668 P
9 F
-0.39 (\277) 424.13 668 P
0 F
-0.39 (\323, and a 64-bit MAC is) 432.02 668 P
-0.73 (to be generated using CBC mode, the key \322) 72 648 P
6 F
-1.74 (abcdef#@) 274.39 648 P
0 F
-0.73 (\323 and the initialization vector ) 331.96 648 P
6 F
-1.74 (0x0) 471.23 648 P
0 F
-0.73 (; the com-) 492.82 648 P
(mand is) 72 628 T
6 F
(bdes -m 64 -k abcdef#@ < ) 136.89 604 T
7 F
(inputf) 316.79 604 T
(ile) 359.97 604 T
6 F
( > ) 381.56 604 T
7 F
(outputf) 403.15 604 T
(ile) 453.52 604 T
0 F
(as CBC is the default encryption mode and ) 72 580 T
6 F
(0x0) 281.2 580 T
0 F
( the default initialization vector:) 302.79 580 T
(text) 72 556 T
6 F
(T) 117 556 T
(h) 144 556 T
(i) 171 556 T
(s) 198 556 T
8 F
(z) 225 556 T
6 F
(i) 252 556 T
(s) 279 556 T
8 F
(z) 306 556 T
6 F
(a) 333 556 T
8 F
(z) 360 556 T
6 F
(t) 387 556 T
(e) 414 556 T
(s) 441 556 T
(t) 468 556 T
9 F
(\277) 495 556 T
0 F
(hex) 72 536 T
10 F
(54) 117 536 T
(68) 144 536 T
(69) 171 536 T
(73) 198 536 T
(20) 225 536 T
(69) 252 536 T
(73) 279 536 T
(20) 306 536 T
(61) 333 536 T
(20) 360 536 T
(74) 387 536 T
(65) 414 536 T
(73) 441 536 T
(74) 468 536 T
(0a) 495 536 T
0 F
(input) 72 516 T
10 F
(54) 117 516 T
(68) 144 516 T
(69) 171 516 T
(73) 198 516 T
(20) 225 516 T
(69) 252 516 T
(73) 279 516 T
(20) 306 516 T
(61) 333 516 T
(20) 360 516 T
(74) 387 516 T
(65) 414 516 T
(73) 441 516 T
(74) 468 516 T
(0a) 495 516 T
[phone] T
0 F
(output) 72 496 T
10 F
(43) 117 496 T
(18) 144 496 T
(de) 171 496 T
(74) 198 496 T
(24) 225 496 T
(a9) 252 496 T
(65) 279 496 T
(d1) 306 496 T
0 F
0.04 (Notice that the text is 15 characters long, so there are 7 bytes following the last full block.) 108 476 P
3 F
(Bdes) 72 456 T
0 F
( pads this to a full block by appending a zero-\336lled byte. The result is then encrypted and the) 95.32 456 T
(last block of output is used as the MAC.) 72 436 T
0.06 (As another example, suppose we used the same text, and wanted a 36-bit MAC to be gen-) 108 412 P
6.91 (erated using 40-bit CFB mode, the key \322) 72 392 P
6 F
16.58 (abcdef#@) 314.9 392 P
0 F
6.91 (\323 and the initialization vector) 372.47 392 P
6 F
(0x0123456789abcdef) 72 372 T
0 F
(; the command is) 201.53 372 T
6 F
(bdes -m 36 -f 40 -v 0x0123456789abcdef < ) 79.32 348 T
7 F
(inputf) 374.36 348 T
(ile) 417.54 348 T
6 F
( > ) 439.13 348 T
7 F
(outputf) 460.71 348 T
(ile) 511.09 348 T
0 F
-0.19 (where ) 72 324 P
4 F
-0.19 (\320m 36) 104.11 324 P
0 F
-0.19 ( is the option to generate a 36-bit MAC, ) 134.91 324 P
4 F
-0.19 (\320f 40) 327.79 324 P
0 F
-0.19 ( indicates 40-bit CFB is to be used, and) 352.58 324 P
4 F
-0.31 (\320v 0x123456789abcdef) 72 304 P
0 F
-0.31 ( sets the initialization vector) 186.62 304 P
-0.31 (. Note that, as the key is not given on the com-) 319.95 304 P
(mand line, the user will be prompted for it. It gives:) 72 284 T
(text) 72 260 T
6 F
(T) 117 260 T
(h) 144 260 T
(i) 171 260 T
(s) 198 260 T
8 F
(z) 225 260 T
6 F
(i) 252 260 T
(s) 279 260 T
8 F
(z) 306 260 T
6 F
(a) 333 260 T
8 F
(z) 360 260 T
6 F
(t) 387 260 T
(e) 414 260 T
(s) 441 260 T
(t) 468 260 T
9 F
(\277) 495 260 T
0 F
(hex) 72 240 T
10 F
(54) 117 240 T
(68) 144 240 T
(69) 171 240 T
(73) 198 240 T
(20) 225 240 T
(69) 252 240 T
(73) 279 240 T
(20) 306 240 T
(61) 333 240 T
(20) 360 240 T
(74) 387 240 T
(65) 414 240 T
(73) 441 240 T
(74) 468 240 T
(0a) 495 240 T
0 F
(input) 72 220 T
10 F
(54) 117 220 T
(68) 144 220 T
(69) 171 220 T
(73) 198 220 T
(20) 225 220 T
(69) 252 220 T
(73) 279 220 T
(20) 306 220 T
(61) 333 220 T
(20) 360 220 T
(74) 387 220 T
(65) 414 220 T
(73) 441 220 T
(74) 468 220 T
(0a) 495 220 T
0 F
(output) 72 200 T
10 F
(2b) 117 200 T
(18) 144 200 T
(68) 171 200 T
(2d) 198 200 T
(60) 225 200 T
0 F
0.19 (Note that the MAC is padded on the right by four zero bits to produce \336ve characters that) 108 180 P
(can be output.) 72 160 T
4 F
(7. Differ) 72 128 T
(ences Between ) 114.41 128 T
1 F
(bdes) 191.01 128 T
4 F
( and Sun\325) 212.99 128 T
(s DES Implementation) 261.88 128 T
0 F
0.02 (The program ) 108 104 P
3 F
0.02 (bdes) 173.33 104 P
0 F
0.02 ( is designed to be completely compatible with Sun Microsystems, Inc.\325) 195.31 104 P
0.02 (s) 535.33 104 P
0.57 (implementation of the Data Encryption Standard, called ) 72 84 P
3 F
0.57 (des) 347.14 84 P
0 F
0.57 ( and described in [4]. Thus, \336les en-) 363.13 84 P
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0.44 (crypted using ) 72 712 P
3 F
0.44 (des) 140.84 712 P
0 F
0.44 ( can be decrypted using ) 156.83 712 P
3 F
0.44 (bdes) 275.29 712 P
0 F
0.44 (, and vice versa, provided modes common to both) 297.27 712 P
-0.34 (are used. However) 72 692 P
-0.34 (, ) 160.41 692 P
3 F
-0.34 (bdes) 166.06 692 P
0 F
-0.34 ( does not allow \336les to be named on the command line, nor does it support) 188.05 692 P
-0.68 (hardware devices \050and so the ) 72 672 P
4 F
-0.68 (-s) 210.83 672 P
0 F
-0.68 ( and ) 219.49 672 P
4 F
-0.68 (-f) 241.45 672 P
0 F
-0.68 ( options of Sun\325) 249.44 672 P
-0.68 (s ) 323.71 672 P
3 F
-0.68 (des) 330.7 672 P
0 F
-0.68 ( are not available\051. Further) 346.69 672 P
-0.68 (, as encryption) 471.07 672 P
-0.05 (is the default, the Sun ) 72 652 P
3 F
-0.05 (des) 179.01 652 P
0 F
-0.05 ( ) 195 652 P
4 F
-0.05 (-e) 197.95 652 P
0 F
-0.05 ( option is not recognized. As the manual page to ) 207.27 652 P
3 F
-0.05 (bdes) 441.6 652 P
0 F
-0.05 ( is in the appen-) 463.59 652 P
(dix, these dif) 72 632 T
(ferences will not be elaborated upon further) 134.08 632 T
(.) 343.24 632 T
0.44 (Sun\325) 108 608 P
0.44 (s ) 130 608 P
3 F