| 1 | .\" -*-nroff-*- |
| 2 | .ie t \{\ |
| 3 | . ds ss \s8\u |
| 4 | . ds se \d\s0 |
| 5 | .\} |
| 6 | .el \{\ |
| 7 | . ds ss ^ |
| 8 | . ds se |
| 9 | .\} |
| 10 | .TH key 1 "5 June 1999" Catacomb |
| 11 | .SH NAME |
| 12 | key \- simple key management system |
| 13 | .SH SYNOPSIS |
| 14 | .B key |
| 15 | .RB [ \-k |
| 16 | .IR keyring ] |
| 17 | .I command |
| 18 | .PP |
| 19 | where |
| 20 | .I command |
| 21 | is one of: |
| 22 | .PP |
| 23 | .B add |
| 24 | .RB [ \-lq ] |
| 25 | .RB [ \-a |
| 26 | .IR alg ] |
| 27 | .RB [ \-b | \-B |
| 28 | .IR bits ] |
| 29 | .RB [ \-p |
| 30 | .IR param ] |
| 31 | .RB [ \-r |
| 32 | .IR tag ] |
| 33 | .br |
| 34 | \h'8n' |
| 35 | .RB [ \-e |
| 36 | .IR expire ] |
| 37 | .RB [ \-t |
| 38 | .IR tag ] |
| 39 | .RB [ \-c |
| 40 | .IR comment ] |
| 41 | .I type |
| 42 | .IR attr ... |
| 43 | .br |
| 44 | .B expire |
| 45 | .IR tag ... |
| 46 | .br |
| 47 | .B delete |
| 48 | .IR tag ... |
| 49 | .br |
| 50 | .B tag |
| 51 | .I tag |
| 52 | .RI [ new-tag ] |
| 53 | .br |
| 54 | .B comment |
| 55 | .I tag |
| 56 | .RI [ comment ] |
| 57 | .br |
| 58 | .B setattr |
| 59 | .I tag |
| 60 | .IR attr ... |
| 61 | .br |
| 62 | .B lock |
| 63 | .I qtag |
| 64 | .br |
| 65 | .B unlock |
| 66 | .I qtag |
| 67 | .br |
| 68 | .B list |
| 69 | .RB [ \-uqv ] |
| 70 | .RB [ \-f |
| 71 | .IR filter ] |
| 72 | .RI [ tag ...] |
| 73 | .br |
| 74 | .B fingerprint |
| 75 | .RB [ \-f |
| 76 | .IR filter ] |
| 77 | .RI [ tag ...] |
| 78 | .br |
| 79 | .B tidy |
| 80 | .br |
| 81 | .B extract |
| 82 | .RB [ \-f |
| 83 | .IR filter ] |
| 84 | .I file |
| 85 | .RI [ tag ...] |
| 86 | .br |
| 87 | .B merge |
| 88 | .I file |
| 89 | .SH DESCRIPTION |
| 90 | The |
| 91 | .B key |
| 92 | command performs useful operations on Catacomb keyring files. It |
| 93 | provides a number of subcommands, by which the various operations may be |
| 94 | carried out. |
| 95 | .SS "Global options" |
| 96 | Before the command name, |
| 97 | .I "global options" |
| 98 | may be given. The following global options are supported: |
| 99 | .TP |
| 100 | .B "\-h, \-\-help" |
| 101 | Writes a brief summary of |
| 102 | .BR key 's |
| 103 | various options to standard output, and |
| 104 | returns a successful exit status. |
| 105 | .TP |
| 106 | .B "\-v, \-\-version" |
| 107 | Writes the program's version number to standard output, and returns a |
| 108 | successful exit status. |
| 109 | .TP |
| 110 | .B "\-u, \-\-usage" |
| 111 | Writes a very terse command line summary to standard output, and returns |
| 112 | a successful exit status. |
| 113 | .TP |
| 114 | .BI "\-k, \-\-keyring " file |
| 115 | Names the keyring file which |
| 116 | .B key |
| 117 | is to process. The default keyring, used if this option doesn't specify |
| 118 | one, is the file named |
| 119 | .B keyring |
| 120 | in the current directory. The keyring must be stored in a regular file: |
| 121 | pipes, sockets, devices etc. are not allowed. |
| 122 | The |
| 123 | .B key |
| 124 | program attempts to lock the keyring before accessing it, using |
| 125 | .BR fcntl (2) |
| 126 | locking. It will however time out after a short while (10 seconds) and |
| 127 | report a failure. |
| 128 | .SS Concepts |
| 129 | In addition to the actual key data itself, a Catacomb key has a number |
| 130 | of other pieces of information attached to it: |
| 131 | .TP |
| 132 | .B "keyid" |
| 133 | Every key has a 32-bit identifying number, written in hexadecimal. |
| 134 | Keyids are not actually related to the key contents: they're generated |
| 135 | randomly. Applications use keyids to refer to specific keys; users are |
| 136 | probably better off with tags and types. A |
| 137 | .I deleted |
| 138 | key cannot be looked up by keyid. |
| 139 | .TP |
| 140 | .B "tag" |
| 141 | A key's tag is a unique string which can be used by users and |
| 142 | applications to identify the key. Tag strings may not contain spaces, |
| 143 | colons or dots. A |
| 144 | .I deleted |
| 145 | key cannot be looked up by tag. Whenever a tag name is wanted, a hex |
| 146 | keyid or key type string can be given instead. |
| 147 | .TP |
| 148 | .B "type" |
| 149 | A key's type string describes what the key may be used for. The type |
| 150 | string is arbitrary, except that it may not contain whitespace |
| 151 | characters, dots or colons. Applications use key types to obtain an |
| 152 | arbitrary but suitable key for some purpose. An |
| 153 | .I expired |
| 154 | key cannot be looked up by type, but may be looked up by keyid or tag. |
| 155 | .TP |
| 156 | .B "key encoding" |
| 157 | There are a number of different ways in which keys can be represented, |
| 158 | according to the uses to which the key will be put. Most symmetric |
| 159 | algorithms use |
| 160 | .I binary |
| 161 | keys. Keys used with number-theoretic systems (like most common |
| 162 | public-key systems) use |
| 163 | .I "multiprecision integer" |
| 164 | keys. Algorithms which require several key constituents (again, like |
| 165 | most public-key systems) use |
| 166 | .I structured |
| 167 | keys, which consist of a collection of named parts. Finally, keys |
| 168 | (including structured keys) can be encrypted. |
| 169 | .TP |
| 170 | .B "filter" |
| 171 | Keys and key components may be selected by a filter expression, a |
| 172 | sequence of flag names separated by commas. Flags are: |
| 173 | .BR binary , |
| 174 | .BR integer , |
| 175 | .B struct |
| 176 | or |
| 177 | .B encrypt |
| 178 | (describing the key encoding); |
| 179 | .BR symmetric , |
| 180 | .BR private , |
| 181 | .B public |
| 182 | or |
| 183 | .B shared |
| 184 | (describing the category of key); |
| 185 | .B burn |
| 186 | and its negation |
| 187 | .B \-burn |
| 188 | (whether the key should be erased from memory after use); and |
| 189 | .B secret |
| 190 | and its negation |
| 191 | .B \-secret |
| 192 | (whether the key is safe to divulge). |
| 193 | .TP |
| 194 | .B "qualified tag" |
| 195 | A key component may be identified by the key's tag (or keyid, or type). |
| 196 | Subcomponents of structured keys are identified by following the tag by |
| 197 | a dot and the name of the subcomponent. |
| 198 | .TP |
| 199 | .B "expiry time" |
| 200 | Most keys expire after a certain amount of time. Once a key has |
| 201 | expired, it will no longer be chosen as a result of a lookup by key |
| 202 | type. However, it is not deleted until its deletion time is also |
| 203 | reached. |
| 204 | .TP |
| 205 | .B "deletion time" |
| 206 | A key's deletion time is the latest expiry time of any of the objects |
| 207 | which require that key. For example, a key used for authenticating |
| 208 | cryptographic cookies should have its deletion time set to the longest |
| 209 | expiry time of any of the cookies it can authenticate. Once a key's |
| 210 | deletion time is passed, it can no longer be referred to by |
| 211 | applications, and will be removed from the keyring next time it's |
| 212 | written to disk. |
| 213 | .TP |
| 214 | .B "comment" |
| 215 | A key may be given a comment when it's created. The comment is for the |
| 216 | benefit of users, and isn't interpreted by applications at all. |
| 217 | (Hopefully.) |
| 218 | .TP |
| 219 | .B "attributes" |
| 220 | A key as zero or more name/value pairs. The names and values are |
| 221 | arbitrary strings, except they may not contain null bytes. Some |
| 222 | attributes may have meaning for particular applications or key types; |
| 223 | others may be assigned global meanings in future. |
| 224 | .SH "COMMAND REFERENCE" |
| 225 | .SS add |
| 226 | The |
| 227 | .B add |
| 228 | command creates a new key and adds it to the keyring. The command |
| 229 | accepts the following options: |
| 230 | .TP |
| 231 | .BI "\-a, \-\-algorithm " alg |
| 232 | Selects a key generation algorithm. The default algorithm is |
| 233 | .BR binary ; |
| 234 | the different algorithms are described below. |
| 235 | .TP |
| 236 | .BI "\-b, \-\-bits " bits |
| 237 | The length of the key to generate, in bits. The default, if this option |
| 238 | is not supplied, depends on the key-generation algorithm. |
| 239 | .TP |
| 240 | .BI "\-B, \-\-qbits " bits |
| 241 | The length of the subsidiary key or parameter, in bits. Not all |
| 242 | key-generation algorithms have a subsidiary key size. |
| 243 | .TP |
| 244 | .BI "\-p, \-\-parameters " tag |
| 245 | Selects a key containing parameter values to copy. Not all |
| 246 | key-generation algorithms allow the use of shared parameters. |
| 247 | .TP |
| 248 | .BI "\-e, \-\-expire " expire |
| 249 | The expiry date for the generated key. This may be the string |
| 250 | .RB ` forever ' |
| 251 | if the key should never expire automatically, or any date acceptable to |
| 252 | the |
| 253 | .BR getdate (3) |
| 254 | library function. Briefly, |
| 255 | .B getdate |
| 256 | understands absolute dates such as |
| 257 | .RB ` 1999-08-02 ' |
| 258 | or |
| 259 | .RB ` "August 2nd, 1999" ', |
| 260 | and (perhaps more usefully) relative dates such as |
| 261 | .RB ` "+2 weeks" '. |
| 262 | The default is to allow a 2 week expiry, which isn't useful. |
| 263 | .TP |
| 264 | .BI "\-c, \-\-comment " comment |
| 265 | Sets a comment for the key. The default is not to attach a comment. |
| 266 | .TP |
| 267 | .BI "\-t, \-\-tag " tag |
| 268 | Selects a tag string for the key. The default is not to set a tag. It |
| 269 | is an error to select a tag which already exists. |
| 270 | .TP |
| 271 | .BI "\-r, \-\-rand-id " tag |
| 272 | Selects the key to use for the random number generator. Catacomb's |
| 273 | random number generator can be |
| 274 | .IR keyed , |
| 275 | so that, even if the inputs to the generator are compromised, knowledge |
| 276 | of the key is also necessary to be able to predict the output. By |
| 277 | default, the latest-expiring key with type |
| 278 | .B catacomb-rand |
| 279 | is used, if present; if not, no key is used. |
| 280 | .TP |
| 281 | .BI "\-l, \-\-lock" |
| 282 | Requests that the secret parts of the newly-generated key be encrypted |
| 283 | using a passphrase. |
| 284 | .TP |
| 285 | .BI "\-q, \-\-quiet" |
| 286 | Suppresses the progress indication which is usually generated while |
| 287 | time-consuming key generation tasks are being performed. |
| 288 | .PP |
| 289 | The key's type is given by the required |
| 290 | .I type |
| 291 | argument. Following the type are zero or more attributes, which are |
| 292 | attached to the key in the same way as for the |
| 293 | .B setattr |
| 294 | command. |
| 295 | .PP |
| 296 | The key-generation algorithms supported are as follows: |
| 297 | .TP |
| 298 | .B "binary" |
| 299 | Generates a plain binary key of the requested length. If the requested |
| 300 | key length is not a multiple of eight, the high-order bits of the first |
| 301 | octet of the key are zeroed. The default key length is 128 bits. |
| 302 | .TP |
| 303 | .B "des" |
| 304 | Generates a DES key, with parity bits. The key length must be 56, 112 |
| 305 | or 168; the default is 56. The low-order bit of each octet is ignored by |
| 306 | the DES algorithm; it is used to give each octet odd parity. |
| 307 | .TP |
| 308 | .B "rsa" |
| 309 | Generates a public/private key pair for use with the RSA algorithm. |
| 310 | .IP |
| 311 | The key components are |
| 312 | .I p |
| 313 | and |
| 314 | .IR q , |
| 315 | a pair of prime numbers; |
| 316 | .IR n , |
| 317 | the product of |
| 318 | .I p |
| 319 | and |
| 320 | .IR q ; |
| 321 | .IR e , |
| 322 | the public exponent; |
| 323 | .IR d , |
| 324 | the private exponent, chosen such that |
| 325 | .IR ed \ \(==\ 1 |
| 326 | (mod |
| 327 | .RI ( p \ \-\ 1)( q \ \-\ 1)); |
| 328 | and some other values useful for optimizing private-key operations: |
| 329 | .IR q \*(ss\-1\*(se\ mod\ p , |
| 330 | .IR d \ mod\ p \ \-\ 1, |
| 331 | and |
| 332 | .IR d \ mod\ q \ \-\ 1. |
| 333 | The values |
| 334 | .I n |
| 335 | and |
| 336 | .I e |
| 337 | constitute the public key; the rest must be kept secret. The key size |
| 338 | requested by the |
| 339 | .B \-b |
| 340 | option determines the size of the modulus |
| 341 | .IR n ; |
| 342 | the default is 1024 bits. |
| 343 | .IP |
| 344 | The key generation algorithm chooses |
| 345 | .I p |
| 346 | and |
| 347 | .I q |
| 348 | to be |
| 349 | .I strong |
| 350 | primes: both |
| 351 | .IR p \ \-\ 1 |
| 352 | and |
| 353 | .IR p \ +\ 1 |
| 354 | have large prime factors \- call them |
| 355 | .I r |
| 356 | and |
| 357 | .I s |
| 358 | respectively \- and |
| 359 | .IR r \ \-\ 1 |
| 360 | also has a large prime factor; |
| 361 | .I q |
| 362 | has similar properties. |
| 363 | .IP |
| 364 | The modulus |
| 365 | .I n |
| 366 | cannot be sensibly used as a shared parameter, since knowledge of |
| 367 | corrssponding public and private exponents is sufficient to be able to |
| 368 | factor the modulus and recover other users' private keys. |
| 369 | .TP |
| 370 | .B "dh-params" |
| 371 | Generates parameters for use with the Diffie-Hellman key exchange |
| 372 | protocol, and many related systems, such as ElGamal encryption and |
| 373 | signatures, and even DSA (although the DSA algorithm is probably better |
| 374 | for this). The parameters are a prime number |
| 375 | .IR q , |
| 376 | a larger prime number |
| 377 | .IR p , |
| 378 | and a generator |
| 379 | .I g |
| 380 | of the |
| 381 | .RI order- q |
| 382 | subgroup of the integers |
| 383 | .RI mod\ p . |
| 384 | .IP |
| 385 | The key size set by the |
| 386 | .B \-b |
| 387 | option determines the size of the modulus |
| 388 | .IR p ; |
| 389 | the size of the generator order |
| 390 | .I q |
| 391 | is set by the |
| 392 | .B \-B |
| 393 | option. The default modulus size is 1024 bits; if no size is specified |
| 394 | for |
| 395 | .IR q , |
| 396 | the parameters are chosen such that |
| 397 | .IR p \ =\ 2 q \ +\ 1, |
| 398 | and |
| 399 | .I |
| 400 | g |
| 401 | is assigned the value 4. This takes much longer. |
| 402 | .IP |
| 403 | If used with the |
| 404 | .B \-p |
| 405 | option, the algorithm simply copies the parameters from an existing key. |
| 406 | .TP |
| 407 | .B "dh" |
| 408 | Generates a public/private key pair for use with offline Diffie-Hellman, |
| 409 | ElGamal, DSA or similar discrete-logarithm-based systems. It selects a |
| 410 | private key |
| 411 | .IR x \ <\ q , |
| 412 | and computes the public key |
| 413 | .IR y \ =\ g\*(ssx\*(se \ mod\ p . |
| 414 | .TP |
| 415 | .B "dsa-param" |
| 416 | Generates parameters for the DSA algorithm. DSA parameters are also |
| 417 | suitable for use with Diffie-Hellman and ElGamal system. |
| 418 | .IP |
| 419 | The main difference between DSA and Diffie-Hellman parameter generation |
| 420 | is thatthe DSA parameter generation |
| 421 | algorithm creates a |
| 422 | .I seed |
| 423 | from which the parameters are derived, and, assuming that the SHA-1 hash |
| 424 | function is strong, it's not feasible to construct a seed from which |
| 425 | deliberately weak parameters are derived. The algorithm used is the one |
| 426 | described in the DSA standard, FIPS\ 186, extended only to allow |
| 427 | sequential search for a prime |
| 428 | .I q |
| 429 | and to allow arbitrary parameter sizes. The seed is stored, |
| 430 | Base64-encoded, as the value of the attribute |
| 431 | .BR seed . |
| 432 | .IP |
| 433 | The default lengths for |
| 434 | .I p |
| 435 | and |
| 436 | .I q |
| 437 | are 768 and 160 bits respectively, since the DSA standard specifies that |
| 438 | .I q |
| 439 | be 160 bits, and the choice of 768 bits for |
| 440 | .I p |
| 441 | gives commensurate security. |
| 442 | .TP |
| 443 | .B "dsa" |
| 444 | Generates a public/private key pair for DSA. As for Diffie-Hellman |
| 445 | keys, it selects a |
| 446 | private key |
| 447 | .IR x \ <\ q , |
| 448 | and computes the public key |
| 449 | .IR y \ =\ g\*(ssx\*(se \ mod\ p . |
| 450 | .TP |
| 451 | .B "bbs" |
| 452 | Generates a public/private key pair for the Blum-Blum-Shub random-number |
| 453 | generator, and the Blum-Goldwasser semantically-secure public-key |
| 454 | encryption system. |
| 455 | .IP |
| 456 | The key components are prime numbers |
| 457 | .I p |
| 458 | and |
| 459 | .IR q , |
| 460 | both congruent to 3 (mod\ 4), and their product |
| 461 | .IR n . |
| 462 | The public key is simply the modulus |
| 463 | .IR n ; |
| 464 | the factors |
| 465 | .I p |
| 466 | and |
| 467 | .I q |
| 468 | are the private key. |
| 469 | .IP |
| 470 | The key-generation algorithm ensures that the two primes |
| 471 | .I p |
| 472 | and |
| 473 | .I q |
| 474 | are |
| 475 | .I strong |
| 476 | (see the discussion of strong primes above, in the section on RSA keys), |
| 477 | and that |
| 478 | .RI ( p \ \-\ 1)/2 |
| 479 | and |
| 480 | .RI ( q \ \-\ 1)/2 |
| 481 | are relatively prime, giving a maximum possible period length. |
| 482 | .IP |
| 483 | The key size requested by the |
| 484 | .B \-b |
| 485 | option determines the length of the modulus |
| 486 | .IR n ; |
| 487 | the default length is 1024 bits. |
| 488 | .SS "expire" |
| 489 | Forces keys to immediately expire. An expired key is not chosen when a |
| 490 | program requests a key by its type. The keys to expire are listed by |
| 491 | their |
| 492 | .IR tag s. |
| 493 | .SS "delete" |
| 494 | Deletes keys immediately. The keys to delete are listed by their |
| 495 | .IR tag s. |
| 496 | Be careful when deleting keys. It might be a better idea |
| 497 | to expire keys rather than deleting them. |
| 498 | .SS "tag" |
| 499 | Sets, deletes or changes the tag attached to a key. The first tag or |
| 500 | keyid names the key to be modified; the second, if present specifies the |
| 501 | new tag to be set. If no second argument is given, the existing tag, if |
| 502 | any, is removed and no new tag is set. |
| 503 | .SS "setattr" |
| 504 | Attaches attributes to a key. The key to which the attributes should be |
| 505 | attached is given by its |
| 506 | .IR tag . |
| 507 | Each attribute has the form |
| 508 | .IB name = value\fR. |
| 509 | An attribute can be deleted by assigning it an empty value. Although |
| 510 | the keyring file format is capable of representing an attribute with an |
| 511 | empty value as distinct from a nonexistant attribute, this interface |
| 512 | does not allow empty attributes to be set. |
| 513 | .SS "comment" |
| 514 | Sets, deletes or changes the comment attached to a key. The first |
| 515 | argument is a key tag or keyid which names the key to be modified; the |
| 516 | second, if present, is the new comment. If no second argument is given, |
| 517 | the existing comment, if any, is removed, and no new comment is set. |
| 518 | .SS "lock" |
| 519 | Locks a key or key component using a passphrase. If the key is already |
| 520 | locked, the existing passphrase is requested, and a new passphrase is |
| 521 | set. |
| 522 | .SS "unlock" |
| 523 | Unlocks a passphrase-locked key or key component. If the key is not |
| 524 | locked, an error is reported. |
| 525 | .SS "list" |
| 526 | Lists the keys in the keyring. A couple of options are supported: |
| 527 | .TP |
| 528 | .B "\-v, \-\-verbose" |
| 529 | Increases the amount of information displayed for each key. Repeat for |
| 530 | a greater effect. |
| 531 | .TP |
| 532 | .B "\-q, \-\-quiet" |
| 533 | Decreases the amount of information displayed for each key. Each use |
| 534 | cancels a |
| 535 | .RB ` \-v ' |
| 536 | option. |
| 537 | .TP |
| 538 | .B "\-u, \-\-utc" |
| 539 | Display key expiry times as UTC rather than using the local time zone. |
| 540 | .TP |
| 541 | .BI "\-f, \-\-filter " filter |
| 542 | Specifies a filter. Only keys and key components which match the filter |
| 543 | are listed. |
| 544 | .PP |
| 545 | By default, a single line of output is generated for each, showing |
| 546 | keyids, types, expiry and deletion dates, and comments. Additional |
| 547 | .RB ` \-v ' |
| 548 | options show more information, such as the exact time of day for expiry |
| 549 | and deletion, key attributes, and a dump of the actual key data. If the |
| 550 | verbosity level is sufficiently high, passphrases are requested to |
| 551 | decrypt locked keys. Make sure nobody is looking over your shoulder |
| 552 | when you do this! |
| 553 | .SS "fingerprint" |
| 554 | Reports a fingerprint (secure hash) on components of requested keys. |
| 555 | The following option is supported: |
| 556 | .TP |
| 557 | .BI "\-f, \-\-filter " filter |
| 558 | Specifies a filter. Only keys and key components which match the filter |
| 559 | are fingerprinted. The default is to only fingerprint nonsecret |
| 560 | components. |
| 561 | .PP |
| 562 | The keys to be fingerprinted are named by their tags or keyids given as |
| 563 | command line arguments. If no key tags are given, all keys which match |
| 564 | the filter are fingerprinted. |
| 565 | .SS "tidy" |
| 566 | Simply reads the keyring from file and writes it back again. This has |
| 567 | the effect of removing any deleted keys from the file. |
| 568 | .SS "extract" |
| 569 | Writes a selection of keys to a file. An option is supported: |
| 570 | .TP |
| 571 | .BI "\-f, \-\-filter " filter |
| 572 | Specifies a filter. Only keys and key components which match the filter |
| 573 | are written. |
| 574 | .PP |
| 575 | Keys extracted are written to the file named by the first argument, |
| 576 | which may be |
| 577 | .RB ` \- ' |
| 578 | to designate standard output. The keys to extract are listed by their |
| 579 | tags; if no tags are given, all keys which match the filter are |
| 580 | extracted. The output is a valid keyring file. |
| 581 | .SS "merge" |
| 582 | Merges the keys from the named |
| 583 | .IR file , |
| 584 | which may be |
| 585 | .RB ` \- ' |
| 586 | to designate standard input, with the keyring. Keys already in the |
| 587 | keyring are not overwritten: you must explicitly remove them first if |
| 588 | you want them to be replaced during the merge. |
| 589 | .SH "SEE ALSO" |
| 590 | .BR keyring (5). |
| 591 | .SH AUTHOR |
| 592 | Mark Wooding, <mdw@nsict.org> |
| 593 | |