31 .TH key 1 "5 June 1999" "Straylight/Edgeware" "Catacomb cryptographic library"
33 key \- simple key management system
149 command performs useful operations on Catacomb keyring files. It
150 provides a number of subcommands, by which the various operations may be
153 Before the command name,
155 may be given. The following global options are supported:
157 .BR "\-h, \-\-help " [ \fIcommand ...]
158 Writes a brief summary of
160 various options to standard output, and
161 returns a successful exit status. With command names, gives help on
164 .B "\-v, \-\-version"
165 Writes the program's version number to standard output, and returns a
166 successful exit status.
169 Writes a very terse command line summary to standard output, and returns
170 a successful exit status.
172 .BI "\-k, \-\-keyring " file
173 Names the keyring file which
175 is to process. The default keyring, used if this option doesn't specify
176 one, is the file named
178 in the current directory. The keyring must be stored in a regular file:
179 pipes, sockets, devices etc. are not allowed.
182 program attempts to lock the keyring before accessing it, using
184 locking. It will however time out after a short while (10 seconds) and
187 In addition to the actual key data itself, a Catacomb key has a number
188 of other pieces of information attached to it:
191 Every key has a 32-bit identifying number, written in hexadecimal.
192 Keyids are not actually related to the key contents: they're generated
193 randomly. Applications use keyids to refer to specific keys; users are
194 probably better off with tags and types. A
196 key cannot be looked up by keyid.
199 A key's tag is a unique string which can be used by users and
200 applications to identify the key. Tag strings may not contain spaces,
203 key cannot be looked up by tag. Whenever a tag name is wanted, a hex
204 keyid or key type string can be given instead.
207 A key's type string describes what the key may be used for. The type
208 string is arbitrary, except that it may not contain whitespace
209 characters, dots or colons. Applications use key types to obtain an
210 arbitrary but suitable key for some purpose. An
212 key cannot be looked up by type, but may be looked up by keyid or tag.
215 There are a number of different ways in which keys can be represented,
216 according to the uses to which the key will be put. Most symmetric
219 keys. Keys used with number-theoretic systems (like most common
220 public-key systems) use
221 .I "multiprecision integer"
222 keys. Elliptic curve systems use
224 keys, which are either a pair of integers representing field elements,
225 or a `point at infinity'. Algorithms which require several key
226 constituents (again, like most public-key systems) use
228 keys, which consist of a collection of named parts. It's possible to
231 as a key, though this is usually done as a component of a structured
232 key. Finally, keys (including structured keys) can be encrypted.
235 Keys and key components may be selected by a filter expression, a
236 sequence of flag names separated by commas. Flags are:
244 (describing the key encoding);
250 (describing the category of key);
254 (whether the key should be erased from memory after use); and
258 (whether the key is safe to divulge).
261 A key component may be identified by the key's tag (or keyid, or type).
262 Subcomponents of structured keys are identified by following the tag by
263 a dot and the name of the subcomponent.
266 Most keys expire after a certain amount of time. Once a key has
267 expired, it will no longer be chosen as a result of a lookup by key
268 type. However, it is not deleted until its deletion time is also
272 A key's deletion time is the latest expiry time of any of the objects
273 which require that key. For example, a key used for authenticating
274 cryptographic cookies should have its deletion time set to the longest
275 expiry time of any of the cookies it can authenticate. Once a key's
276 deletion time is passed, it can no longer be referred to by
277 applications, and will be removed from the keyring next time it's
281 A key may be given a comment when it's created. The comment is for the
282 benefit of users, and isn't interpreted by applications at all.
286 A key has zero or more name/value pairs. The names and values are
287 arbitrary strings, except that they may not contain null bytes. Some
288 attributes may have meaning for particular applications or key types;
289 others may be assigned global meanings in future.
290 .SH "COMMAND REFERENCE"
294 command behaves exactly as the
296 option. With no arguments, it shows an overview of
298 options; with arguments, it describes the named subcommands.
302 command prints various lists of tokens understood by
304 With no arguments, it prints all of the lists; with arguments, it prints
305 just the named lists, in order. The recognized lists can be enumerated
310 command. The lists are as follows.
313 The lists which can be enumerated by the
318 The hash functions which can be used with the
325 The built-in elliptic curves which can be used with the
330 The built-in Diffie\(enHellman groups which can be used with the
335 The key-generation algorithms which are acceptable to the
342 The pseudorandom generators which are acceptable to the
349 Fingerprint presentation styles, as used by the
357 command creates a new key and adds it to the keyring. The command
358 accepts the following options:
360 .BI "\-a, \-\-algorithm " alg
361 Selects a key generation algorithm. The default algorithm is
363 the different algorithms are described below. The command
365 lists the recognized key-generation algorithms.
367 .BI "\-b, \-\-bits " bits
368 The length of the key to generate, in bits. The default, if this option
369 is not supplied, depends on the key-generation algorithm.
371 .BI "\-B, \-\-qbits " bits
372 The length of the subsidiary key or parameter, in bits. Not all
373 key-generation algorithms have a subsidiary key size.
375 .BI "\-p, \-\-parameters " tag
376 Selects a key containing parameter values to copy. Not all
377 key-generation algorithms allow the use of shared parameters. A new key
378 also inherits attributes from its parameter key.
380 .BI "\-A, \-\-seedalg " seed-alg
381 Use the deterministic random number generator algorithm
383 to generate the key. Use
389 options; without one of these,
391 has no effect. The default algorithm is
395 shows a list of recognized seeding algorithms. The seeding algorithm
396 used to generate a key is recorded as the key's
400 .BI "\-s, \-\-seed " seed
401 Generate the key deterministically using the given
403 which should be a Base64-encoded binary string. This is mainly useful
404 for parameters keys (types
408 to demonstrate that a set of parameters has been generated in an honest
411 generation algorithm can be used to generate
413 keys as required by FIPS186. The requested seed is recorded,
414 Base64-encoded, as the new key's
418 .BI "\-n, \-\-newseed " bits
419 Generate a new seed, with the given length in
421 The generated seed is recorded, Base64-encoded, as the new key's
425 .BI "\-e, \-\-expire " expire
426 The expiry date for the generated key. This may be the string
428 if the key should never expire automatically, or any date acceptable to
431 library function. Briefly,
433 understands absolute dates such as
436 .RB ` "August 2nd, 1999" ',
437 and (perhaps more usefully) relative dates such as
439 The default is to allow a 2 week expiry, which isn't useful.
441 .BI "\-c, \-\-comment " comment
442 Sets a comment for the key. The default is not to attach a comment.
444 .BI "\-C, \-\-curve " curve-spec
445 Use the elliptic curve described by
447 when generating elliptic curve parameters.
449 .BI "\-t, \-\-tag " tag
450 Selects a tag string for the key. The default is not to set a tag. It
451 is an error to select a tag which already exists.
456 option is given, remove this tag from any key which already has it.
458 .BI "\-R, \-\-rand-id " tag
459 Selects the key to use for the random number generator. Catacomb's
460 random number generator can be
462 so that, even if the inputs to the generator are compromised, knowledge
463 of the key is also necessary to be able to predict the output. By
464 default, the latest-expiring key with type
466 is used, if present; if not, no key is used.
469 Requests that the secret parts of the newly-generated key be encrypted
473 Suppresses the progress indication which is usually generated while
474 time-consuming key generation tasks are being performed.
476 .BI "\-L, \-\-lim-lee"
477 When generating Diffie\(enHellman parameters, generate a Lim\(enLee
478 prime rather than a random (or safe) prime. See the details on
479 Diffie\(enHellman key generation below.
482 When generating Diffie\(enHellman parameters, generate a KCDSA-style
483 Lim\(enLee prime rather than a random (or safe) prime. See the details
484 on Diffie\(enHellman key generation below.
486 .BI "\-S, \-\-subgroup"
487 When generating Diffie\(enHellman parameters with a Lim\(enLee prime,
488 choose a generator of a prime-order subgroup rather than a subgroup of
490 .RI ( p "\ \-\ 1)/2."
492 The key's type is given by the required
494 argument. Following the type are zero or more attributes, which are
495 attached to the key in the same way as for the
499 The key-generation algorithms supported are as follows:
502 Generates a plain binary key of the requested length. If the requested
503 key length is not a multiple of eight, the high-order bits of the first
504 octet of the key are zeroed. The default key length is 128 bits.
507 Generates a DES key, with parity bits. The key length must be 56, 112
508 or 168; the default is 56. The low-order bit of each octet is ignored by
509 the DES algorithm; it is used to give each octet odd parity.
512 Generates a public/private key pair for use with the RSA algorithm.
514 The key components are
518 a pair of prime numbers;
527 the private exponent, chosen such that
530 .RI lcm( p "\~\-\~1, " q \~\-\~1));
531 and some other values useful for optimizing private-key operations:
532 .IR q "\*(ss\-1\*(se mod " p ,
533 .IR d "\~mod " p \~\-\~1,
535 .IR d "\~mod " q \~\-\~1.
540 constitute the public key; the rest must be kept secret. The key size
543 option determines the size of the modulus
545 the default is 1024 bits.
547 The key generation algorithm chooses
557 have large prime factors \(en call them
561 respectively \(en and
563 also has a large prime factor;
565 has similar properties.
569 cannot be sensibly used as a shared parameter, since knowledge of
570 corrssponding public and private exponents is sufficient to be able to
571 factor the modulus and recover other users' private keys.
574 Generates parameters for use with the Diffie\(enHellman key exchange
575 protocol, and many related systems, such as ElGamal encryption and
576 signatures, and even DSA. (The separate DSA algorithm uses the
577 generator described in FIPS186-1.)
579 The Diffie\(enHellman parameters are a prime modulus
590 option controls the size of the modulus
592 the default size is 1024 bits.
596 size is selected using the
598 option and the Lim\(enLee prime options are disabled, then
600 is chosen to be a `safe' prime (i.e.,
601 .IR p "\~= 2" q \~+\~1,
604 prime). Finding safe primes takes a very long time. In this case, the
609 If a size is chosen for
611 and Lim\(enLee primes are not selected then the prime
622 option was given, Lim\(enLee primes are selected: the parameters are
624 .IR p "\~= 2\~" q \*(us0\*(ue
626 .IR q \*(us2\*(ue\~...\~+\~1,
629 are primes at least as large as the setting given by the
631 option (or 256 bits, if no setting was given).
635 option was given, KCDSA-style Lim\(enLee primes are selected: the
636 parameters are chosen such that
637 .IR p "\~= 2" qv \~+\~1,
649 options were given, the generator
651 is chosen to generate the subgroup of order
655 will generate the group of order
656 .RI ( p "\~\-\~1)/2\~= " q "\*(us0\*(ue " q \*(us1\*(ue
657 .IR q \*(us2\*(ue\~...
661 option can be given, in which case the parameters are taken directly
662 from the provided group specification, which may either be the the name
663 of one of the built-in groups (say
665 for a list) or a triple
666 .RI ( p ,\~ q ,\~ g ).
667 separated by commas. No random generation is done in this case: the
668 given parameters are simply stored.
671 Generates a public/private key pair for use with offline Diffie\(enHellman,
672 ElGamal, DSA or similar discrete-logarithm-based systems. It selects a
675 and computes the public key
676 .IR y "\~= " g \*(ss x "\*(se mod\~" p .
679 Generates parameters for the DSA algorithm. DSA parameters are also
680 suitable for use with Diffie\(enHellman and ElGamal system.
682 The main difference between DSA and Diffie\(enHellman parameter generation
683 is thatthe DSA parameter generation
686 from which the parameters are derived, and, assuming that the SHA-1 hash
687 function is strong, it's not feasible to construct a seed from which
688 deliberately weak parameters are derived. The algorithm used is the one
689 described in the DSA standard, FIPS\ 186, extended only to allow
690 sequential search for a prime
692 and to allow arbitrary parameter sizes. The seed is stored,
693 Base64-encoded, as the value of the attribute
696 The default lengths for
700 are 768 and 160 bits respectively, since the DSA standard specifies that
702 be 160 bits, and the choice of 768 bits for
704 gives commensurate security.
707 Generates a public/private key pair for DSA. As for Diffie\(enHellman
711 and computes the public key
712 .IR y "\~= " g \*(ss x "\*(se mod\~" p .
715 Generates a public/private key pair for the Blum-Blum-Shub random-number
716 generator, and the Blum-Goldwasser semantically-secure public-key
719 The key components are prime numbers
723 both congruent to 3 (mod\~4), and their product
725 The public key is simply the modulus
733 The key-generation algorithm ensures that the two primes
739 (see the discussion of strong primes above, in the section on RSA keys),
744 are relatively prime, giving a maximum possible period length.
746 The key size requested by the
748 option determines the length of the modulus
750 the default length is 1024 bits.
753 Store an elliptic curve specification. If no explicit
757 option) then a curve is chosen whose order is about the size given by the
759 option (default is 256 bits).
763 can be given explicitly (in which case
765 is ignored). It can either be the name of a built-in curve (say
767 for a list of curve names) or a full specification. The curve is
768 checked for correctness and security according to the SEC1
769 specification: failed checks cause a warning to be issued to standard
770 error (though the program continues anyway). The check can be
775 A curve specification consists of the following elements optionally
776 separated by whitespace: a
792 and the representation of the normal element \*(*b; an optional
802 (the `proj' types currently have much better performance);
805 the two field-element parameters
809 which define the elliptic curve
811 separated by an optional
819 of the generator point
821 separated by an optional
827 of the group generated by
838 Generate a private scalar and a corresponding public point on an
841 above for how to specify elliptic curve parameter sets. The scalar
843 is chosen unformly between 0 and the curve order
845 the public point is then
850 Forces keys to immediately expire. An expired key is not chosen when a
851 program requests a key by its type. The keys to expire are listed by
855 Deletes keys immediately. The keys to delete are listed by their
857 Be careful when deleting keys. It might be a better idea
858 to expire keys rather than deleting them.
860 Sets, deletes or changes the tag attached to a key. The first tag or
861 keyid names the key to be modified; the second, if present specifies the
862 new tag to be set. If no second argument is given, the existing tag, if
863 any, is removed and no new tag is set. It is an error to set a tag
864 which already exists on another key, unless you give the
866 option, which removes the tag first.
868 Attaches attributes to a key. The key to which the attributes should be
869 attached is given by its
871 Each attribute has the form
873 An attribute can be deleted by assigning it an empty value. Although
874 the keyring file format is capable of representing an attribute with an
875 empty value as distinct from a nonexistant attribute, this interface
876 does not allow empty attributes to be set.
878 Fetches a single attribute of a key. The key whose attribute is to be
881 The attribute's value is written to standard output followed by a
882 newline. If the key or attribute is absent, a message is written to
883 standard error and the program exits nonzero.
885 Sets, deletes or changes the comment attached to a key. The first
886 argument is a key tag or keyid which names the key to be modified; the
887 second, if present, is the new comment. If no second argument is given,
888 the existing comment, if any, is removed, and no new comment is set.
890 Locks a key or key component using a passphrase. If the key is already
891 locked, the existing passphrase is requested, and a new passphrase is
894 Unlocks a passphrase-locked key or key component. If the key is not
895 locked, an error is reported.
897 Lists the keys in the keyring. A couple of options are supported:
899 .B "\-v, \-\-verbose"
900 Increases the amount of information displayed for each key. Repeat for
904 Decreases the amount of information displayed for each key. Each use
910 Display key expiry times as UTC rather than using the local time zone.
912 .BI "\-f, \-\-filter " filter
913 Specifies a filter. Only keys and key components which match the filter
916 By default, a single line of output is generated for each, showing
917 keyids, types, expiry and deletion dates, and comments. Additional
919 options show more information, such as the exact time of day for expiry
920 and deletion, key attributes, and a dump of the actual key data. If the
921 verbosity level is sufficiently high, passphrases are requested to
922 decrypt locked keys. Make sure nobody is looking over your shoulder
925 Reports a fingerprint (secure hash) on components of requested keys.
926 The following options are supported:
928 .BI "\-f, \-\-filter " filter
929 Specifies a filter. Only keys and key components which match the filter
930 are fingerprinted. The default is to only fingerprint nonsecret
933 .BI "\-p, \-\-presentation " style
934 Write fingerprints in the given
936 See below for a list of presentation styles.
938 .BI "\-a, \-\-algorithm " hash
939 Names the hashing algorithm. Run
941 for a list of hashing algorithms. The default is
944 The keys to be fingerprinted are named by their tags or keyids given as
945 command line arguments. If no key tags are given, all keys which match
946 the filter are fingerprinted. See
948 for a description of how key fingerprints are computed.
950 The fingerprint may be shown in the following styles.
953 Lowercase hexadecimal, with groups of eight digits separated by hyphens
954 (`\-'). This is the default presentation style. (On input, colons are
955 also permitted as separators.)
958 Lowercase Base32 encoding, without `=' padding, with groups of six
959 digits separated by colons (`:'). (On input, padding characters are
962 Check a key's fingerprint against a reference copy. The following
963 options are supported:
965 .BI "\-f, \-\-filter " filter
966 Specifies a filter. Only key components which match the filter are
967 hashed. The default is to only fingerprint nonsecret components. An
968 error is reported if no part of the key matches.
970 .BI "\-p, \-\-presentation " style
973 to be in the given presentation
975 These match the styles produced by the
977 command described above.
979 .BI "\-a, \-\-algorithm " hash
980 Names the hashing algorithm. Run
982 for a list of hashing algorithms. The default is
985 The fingerprint should be provided in the form printed by the
987 command, using the same presentation
989 A little flexibility is permitted: separators may be placed anywhere (or
990 not at all) and are ignored; whitespace is permitted and ignored; and
991 case is ignored in presentation styles which don't make use of both
992 upper- and lower-case characters.
994 Simply reads the keyring from file and writes it back again. This has
995 the effect of removing any deleted keys from the file.
997 Writes a selection of keys to a file. An option is supported:
999 .BI "\-f, \-\-filter " filter
1000 Specifies a filter. Only keys and key components which match the filter
1003 Keys extracted are written to the file named by the first argument,
1006 to designate standard output. The keys to extract are listed by their
1007 tags; if no tags are given, all keys which match the filter are
1008 extracted. The output is a valid keyring file.
1010 Merges the keys from the named
1014 to designate standard input, with the keyring. Keys already in the
1015 keyring are not overwritten: you must explicitly remove them first if
1016 you want them to be replaced during the merge.
1020 Mark Wooding, <mdw@distorted.org.uk>