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diff --git a/doc/DETAILS b/doc/DETAILS deleted file mode 100644 index 1ba9df159..000000000 --- a/doc/DETAILS +++ /dev/null @@ -1,990 +0,0 @@ - -Format of colon listings -======================== -First an example: - -$ gpg --fixed-list-mode --with-colons --list-keys \ - --with-fingerprint --with-fingerprint wk@gnupg.org - -pub:f:1024:17:6C7EE1B8621CC013:899817715:1055898235::m:::scESC: -fpr:::::::::ECAF7590EB3443B5C7CF3ACB6C7EE1B8621CC013: -uid:f::::::::Werner Koch <wk@g10code.com>: -uid:f::::::::Werner Koch <wk@gnupg.org>: -sub:f:1536:16:06AD222CADF6A6E1:919537416:1036177416:::::e: -fpr:::::::::CF8BCC4B18DE08FCD8A1615906AD222CADF6A6E1: -sub:r:1536:20:5CE086B5B5A18FF4:899817788:1025961788:::::esc: -fpr:::::::::AB059359A3B81F410FCFF97F5CE086B5B5A18FF4: - -The double --with-fingerprint prints the fingerprint for the subkeys -too, --fixed-list-mode is themodern listing way printing dates in -seconds since Epoch and does not merge the first userID with the pub -record. - - - 1. Field: Type of record - pub = public key - crt = X.509 certificate - crs = X.509 certificate and private key available - sub = subkey (secondary key) - sec = secret key - ssb = secret subkey (secondary key) - uid = user id (only field 10 is used). - uat = user attribute (same as user id except for field 10). - sig = signature - rev = revocation signature - fpr = fingerprint: (fingerprint is in field 10) - pkd = public key data (special field format, see below) - grp = reserved for gpgsm - rvk = revocation key - - 2. Field: A letter describing the calculated trust. This is a single - letter, but be prepared that additional information may follow - in some future versions. (not used for secret keys) - o = Unknown (this key is new to the system) - i = The key is invalid (e.g. due to a missing self-signature) - d = The key has been disabled - r = The key has been revoked - e = The key has expired - - = Unknown trust (i.e. no value assigned) - q = Undefined trust - '-' and 'q' may safely be treated as the same - value for most purposes - n = Don't trust this key at all - m = There is marginal trust in this key - f = The key is full trusted. - u = The key is ultimately trusted; this is only used for - keys for which the secret key is also available. - 3. Field: length of key in bits. - 4. Field: Algorithm: 1 = RSA - 16 = ElGamal (encrypt only) - 17 = DSA (sometimes called DH, sign only) - 20 = ElGamal (sign and encrypt) - (for other id's see include/cipher.h) - 5. Field: KeyID either of - 6. Field: Creation Date (in UTC) - 7. Field: Key expiration date or empty if none. - 8. Field: Used for serial number in crt records (used to be the Local-ID) - 9. Field: Ownertrust (primary public keys only) - This is a single letter, but be prepared that additional - information may follow in some future versions. -10. Field: User-ID. The value is quoted like a C string to avoid - control characters (the colon is quoted "\x3a"). - This is not used with --fixed-list-mode in gpg. - A UAT record puts the attribute subpacket count here, a - space, and then the total attribute subpacket size. - In gpgsm the issuer name comes here - An FPR record stores the fingerprint here. - The fingerprint of an revocation key is stored here. -11. Field: Signature class. This is a 2 digit hexnumber followed by - either the letter 'x' for an exportable signature or the - letter 'l' for a local-only signature. - The class byte of an revocation key is also given here, - 'x' and 'l' ist used the same way. -12. Field: Key capabilities: - e = encrypt - s = sign - c = certify - A key may have any combination of them. The primary key has in - addition to these letters, uppercase version of the letter to - denote the _usable_ capabilities of the entire key. -13. Field: Used in FPR records for S/MIME keys to store the fingerprint of - the issuer certificate. This is useful to build the - certificate path based on certificates stored in the local - keyDB; it is only filled if the issue certificate is - available. The advantage of using this value is that it is - guaranteed to have been been build by the same lookup - algorithm as gpgsm uses. - For "uid" recods this lists the preferences n the sameway the - -edit menu does. -14. Field Flag field used in the --edit menu output: - - -All dates are displayed in the format yyyy-mm-dd unless you use the -option --fixed-list-mode in which case they are displayed as seconds -since Epoch. More fields may be added later, so parsers should be -prepared for this. When parsing a number the parser should stop at the -first non-number character so that additional information can later be -added. - -If field 1 has the tag "pkd", a listing looks like this: -pkd:0:1024:B665B1435F4C2 .... FF26ABB: - ! ! !-- the value - ! !------ for information number of bits in the value - !--------- index (eg. DSA goes from 0 to 3: p,q,g,y) - - - -Format of the "--status-fd" output -================================== -Every line is prefixed with "[GNUPG:] ", followed by a keyword with -the type of the status line and a some arguments depending on the -type (maybe none); an application should always be prepared to see -more arguments in future versions. - - - GOODSIG <long keyid> <username> - The signature with the keyid is good. For each signature only - one of the three codes GOODSIG, BADSIG or ERRSIG will be - emitted and they may be used as a marker for a new signature. - The username is the primary one encoded in UTF-8 and %XX - escaped. - - EXPSIG <long keyid> <username> - The signature with the keyid is good, but the signature is - expired. The username is the primary one encoded in UTF-8 and - %XX escaped. - - EXPKEYSIG <long keyid> <username> - The signature with the keyid is good, but the signature was - made by an expired key. The username is the primary one - encoded in UTF-8 and %XX escaped. - - BADSIG <long keyid> <username> - The signature with the keyid has not been verified okay. - The username is the primary one encoded in UTF-8 and %XX - escaped. - - ERRSIG <long keyid> <pubkey_algo> <hash_algo> \ - <sig_class> <timestamp> <rc> - It was not possible to check the signature. This may be - caused by a missing public key or an unsupported algorithm. - A RC of 4 indicates unknown algorithm, a 9 indicates a missing - public key. The other fields give more information about - this signature. sig_class is a 2 byte hex-value. - - VALIDSIG <fingerprint in hex> <sig_creation_date> <sig-timestamp> - <expire-timestamp> - - The signature with the keyid is good. This is the same - as GOODSIG but has the fingerprint as the argument. Both - status lines are emitted for a good signature. - sig-timestamp is the signature creation time in seconds after - the epoch. expire-timestamp is the signature expiration time - in seconds after the epoch (zero means "does not expire"). - - SIG_ID <radix64_string> <sig_creation_date> <sig-timestamp> - This is emitted only for signatures of class 0 or 1 which - have been verified okay. The string is a signature id - and may be used in applications to detect replay attacks - of signed messages. Note that only DLP algorithms give - unique ids - others may yield duplicated ones when they - have been created in the same second. - - ENC_TO <long keyid> <keytype> <keylength> - The message is encrypted to this keyid. - keytype is the numerical value of the public key algorithm, - keylength is the length of the key or 0 if it is not known - (which is currently always the case). - - NODATA <what> - No data has been found. Codes for what are: - 1 - No armored data. - 2 - Expected a packet but did not found one. - 3 - Invalid packet found, this may indicate a non OpenPGP message. - You may see more than one of these status lines. - - UNEXPECTED <what> - Unexpected data has been encountered - 0 - not further specified 1 - - - TRUST_UNDEFINED <error token> - TRUST_NEVER <error token> - TRUST_MARGINAL - TRUST_FULLY - TRUST_ULTIMATE - For good signatures one of these status lines are emitted - to indicate how trustworthy the signature is. The error token - values are currently only emiited by gpgsm. - - SIGEXPIRED - This is deprecated in favor of KEYEXPIRED. - - KEYEXPIRED <expire-timestamp> - The key has expired. expire-timestamp is the expiration time - in seconds after the epoch. - - KEYREVOKED - The used key has been revoked by its owner. No arguments yet. - - BADARMOR - The ASCII armor is corrupted. No arguments yet. - - RSA_OR_IDEA - The IDEA algorithms has been used in the data. A - program might want to fallback to another program to handle - the data if GnuPG failed. This status message used to be emitted - also for RSA but this has been dropped after the RSA patent expired. - However we can't change the name of the message. - - SHM_INFO - SHM_GET - SHM_GET_BOOL - SHM_GET_HIDDEN - - GET_BOOL - GET_LINE - GET_HIDDEN - GOT_IT - - NEED_PASSPHRASE <long main keyid> <long keyid> <keytype> <keylength> - Issued whenever a passphrase is needed. - keytype is the numerical value of the public key algorithm - or 0 if this is not applicable, keylength is the length - of the key or 0 if it is not known (this is currently always the case). - - NEED_PASSPHRASE_SYM <cipher_algo> <s2k_mode> <s2k_hash> - Issued whenever a passphrase for symmetric encryption is needed. - - MISSING_PASSPHRASE - No passphrase was supplied. An application which encounters this - message may want to stop parsing immediately because the next message - will probably be a BAD_PASSPHRASE. However, if the application - is a wrapper around the key edit menu functionality it might not - make sense to stop parsing but simply ignoring the following - BAD_PASSPHRASE. - - BAD_PASSPHRASE <long keyid> - The supplied passphrase was wrong or not given. In the latter case - you may have seen a MISSING_PASSPHRASE. - - GOOD_PASSPHRASE - The supplied passphrase was good and the secret key material - is therefore usable. - - DECRYPTION_FAILED - The symmetric decryption failed - one reason could be a wrong - passphrase for a symmetrical encrypted message. - - DECRYPTION_OKAY - The decryption process succeeded. This means, that either the - correct secret key has been used or the correct passphrase - for a conventional encrypted message was given. The program - itself may return an errorcode because it may not be possible to - verify a signature for some reasons. - - NO_PUBKEY <long keyid> - NO_SECKEY <long keyid> - The key is not available - - IMPORTED <long keyid> <username> - The keyid and name of the signature just imported - - IMPORT_OK <reason> [<fingerprint>] - The key with the primary key's FINGERPRINT has been imported. - Reason flags: - 0 := Not actually changed - 1 := Entirely new key. - 2 := New user IDs - 4 := New signatures - 8 := New subkeys - 16 := Contains private key. - The flags may be ORed. - - IMPORT_PROBLEM <reason> [<fingerprint>] - Issued for each import failure. Reason codes are: - 0 := "No specific reason given". - 1 := "Invalid Certificate". - 2 := "Issuer Certificate missing". - 3 := "Certificate Chain too long". - 4 := "Error storing certificate". - - IMPORT_RES <count> <no_user_id> <imported> <imported_rsa> <unchanged> - <n_uids> <n_subk> <n_sigs> <n_revoc> <sec_read> <sec_imported> <sec_dups> <not_imported> - Final statistics on import process (this is one long line) - - FILE_START <what> <filename> - Start processing a file <filename>. <what> indicates the performed - operation: - 1 - verify - 2 - encrypt - 3 - decrypt - - FILE_DONE - Marks the end of a file processing which has been started - by FILE_START. - - BEGIN_DECRYPTION - END_DECRYPTION - Mark the start and end of the actual decryption process. These - are also emitted when in --list-only mode. - - BEGIN_ENCRYPTION <mdc_method> <sym_algo> - END_ENCRYPTION - Mark the start and end of the actual encryption process. - - DELETE_PROBLEM reason_code - Deleting a key failed. Reason codes are: - 1 - No such key - 2 - Must delete secret key first - 3 - Ambigious specification - - PROGRESS what char cur total - Used by the primegen and Public key functions to indicate progress. - "char" is the character displayed with no --status-fd enabled, with - the linefeed replaced by an 'X'. "cur" is the current amount - done and "total" is amount to be done; a "total" of 0 indicates that - the total amount is not known. 100/100 may be used to detect the - end of operation. - - SIG_CREATED <type> <pubkey algo> <hash algo> <class> <timestamp> <key fpr> - A signature has been created using these parameters. - type: 'D' = detached - 'C' = cleartext - 'S' = standard - (only the first character should be checked) - class: 2 hex digits with the signature class - - KEY_CREATED <type> <fingerprint> - A key has been created - type: 'B' = primary and subkey - 'P' = primary - 'S' = subkey - The fingerprint is one of the primary key for type B and P and - the one of the subkey for S. - - SESSION_KEY <algo>:<hexdigits> - The session key used to decrypt the message. This message will - only be emmited when the special option --show-session-key - is used. The format is suitable to be passed to the option - --override-session-key - - NOTATION_NAME <name> - NOTATION_DATA <string> - name and string are %XX escaped; the data may be splitted - among several notation_data lines. - - USERID_HINT <long main keyid> <string> - Give a hint about the user ID for a certain keyID. - - POLICY_URL <string> - string is %XX escaped - - BEGIN_STREAM - END_STREAM - Issued by pipemode. - - INV_RECP <reason> <requested_recipient> - Issued for each unusable recipient. The reasons codes - currently in use are: - 0 := "No specific reason given". - 1 := "Not Found" - 2 := "Ambigious specification" - 3 := "Wrong key usage" - 4 := "Key revoked" - 5 := "Key expired" - 6 := "No CRL known" - 7 := "CRL too old" - 8 := "Policy mismatch" - 9 := "Not a secret key" - 10 := "Key not trusted" - - Note that this status is also used for gpgsm's SIGNER command - where it relates to signer's of course. - - NO_RECP <reserved> - Issued when no recipients are usable. - - ALREADY_SIGNED <long-keyid> - Warning: This is experimental and might be removed at any time. - - TRUNCATED <maxno> - The output was truncated to MAXNO items. This status code is issued - for certain external requests - - ERROR <error location> <error code> - This is a generic error status message, it might be followed - by error location specific data. <error token> and - <error_location> should not contain a space. - - ATTRIBUTE <fpr> <octets> <type> <index> <count> - <timestamp> <expiredate> <flags> - This is one long line issued for each attribute subpacket when - an attribute packet is seen during key listing. <fpr> is the - fingerprint of the key. <octets> is the length of the - attribute subpacket. <type> is the attribute type - (1==image). <index>/<count> indicates that this is the Nth - indexed subpacket of count total subpackets in this attribute - packet. <timestamp> and <expiredate> are from the - self-signature on the attribute packet. If the attribute - packet does not have a valid self-signature, then the - timestamp is 0. <flags> are a bitwise OR of: - 0x01 = this attribute packet is a primary uid - 0x02 = this attribute packet is revoked - 0x04 = this attribute packet is expired - - -Key generation -============== - Key generation shows progress by printing different characters to - stderr: - "." Last 10 Miller-Rabin tests failed - "+" Miller-Rabin test succeeded - "!" Reloading the pool with fresh prime numbers - "^" Checking a new value for the generator - "<" Size of one factor decreased - ">" Size of one factor increased - - The prime number for ElGamal is generated this way: - - 1) Make a prime number q of 160, 200, 240 bits (depending on the keysize) - 2) Select the length of the other prime factors to be at least the size - of q and calculate the number of prime factors needed - 3) Make a pool of prime numbers, each of the length determined in step 2 - 4) Get a new permutation out of the pool or continue with step 3 - if we have tested all permutations. - 5) Calculate a candidate prime p = 2 * q * p[1] * ... * p[n] + 1 - 6) Check that this prime has the correct length (this may change q if - it seems not to be possible to make a prime of the desired length) - 7) Check whether this is a prime using trial divisions and the - Miller-Rabin test. - 8) Continue with step 4 if we did not find a prime in step 7. - 9) Find a generator for that prime. - - This algorithm is based on Lim and Lee's suggestion from the - Crypto '97 proceedings p. 260. - - -Unattended key generation -========================= -This feature allows unattended generation of keys controlled by a -parameter file. To use this feature, you use --gen-key together with ---batch and feed the parameters either from stdin or from a file given -on the commandline. - -The format of this file is as follows: - o Text only, line length is limited to about 1000 chars. - o You must use UTF-8 encoding to specify non-ascii characters. - o Empty lines are ignored. - o Leading and trailing spaces are ignored. - o A hash sign as the first non white space character indicates a comment line. - o Control statements are indicated by a leading percent sign, the - arguments are separated by white space from the keyword. - o Parameters are specified by a keyword, followed by a colon. Arguments - are separated by white space. - o The first parameter must be "Key-Type", control statements - may be placed anywhere. - o Key generation takes place when either the end of the parameter file - is reached, the next "Key-Type" parameter is encountered or at the - control statement "%commit" - o Control statements: - %echo <text> - Print <text>. - %dry-run - Suppress actual key generation (useful for syntax checking). - %commit - Perform the key generation. An implicit commit is done - at the next "Key-Type" parameter. - %pubring <filename> - %secring <filename> - Do not write the key to the default or commandline given - keyring but to <filename>. This must be given before the first - commit to take place, duplicate specification of the same filename - is ignored, the last filename before a commit is used. - The filename is used until a new filename is used (at commit points) - and all keys are written to that file. If a new filename is given, - this file is created (and overwrites an existing one). - Both control statements must be given. - o The order of the parameters does not matter except for "Key-Type" - which must be the first parameter. The parameters are only for the - generated keyblock and parameters from previous key generations are not - used. Some syntactically checks may be performed. - The currently defined parameters are: - Key-Type: <algo-number>|<algo-string> - Starts a new parameter block by giving the type of the - primary key. The algorithm must be capable of signing. - This is a required parameter. - Key-Length: <length-in-bits> - Length of the key in bits. Default is 1024. - Key-Usage: <usage-list> - Space or comma delimited list of key usage, allowed values are - "encrypt" and "sign". This is used to generate the key flags. - Please make sure that the algorithm is capable of this usage. - Subkey-Type: <algo-number>|<algo-string> - This generates a secondary key. Currently only one subkey - can be handled. - Subkey-Length: <length-in-bits> - Length of the subkey in bits. Default is 1024. - Subkey-Usage: <usage-list> - Similar to Key-Usage. - Passphrase: <string> - If you want to specify a passphrase for the secret key, - enter it here. Default is not to use any passphrase. - Name-Real: <string> - Name-Comment: <string> - Name-Email: <string> - The 3 parts of a key. Remember to use UTF-8 here. - If you don't give any of them, no user ID is created. - Expire-Date: <iso-date>|(<number>[d|w|m|y]) - Set the expiration date for the key (and the subkey). It - may either be entered in ISO date format (2000-08-15) or as - number of days, weeks, month or years. Without a letter days - are assumed. - Preferences: <string> - Set the cipher, hash, and compression preference values for - this key. This expects the same type of string as "setpref" - in the --edit menu. - Revoker: <algo>:<fpr> [sensitive] - Add a designated revoker to the generated key. Algo is the - public key algorithm of the designated revoker (i.e. RSA=1, - DSA=17, etc.) Fpr is the fingerprint of the designated - revoker. The optional "sensitive" flag marks the designated - revoker as sensitive information. Only v4 keys may be - designated revokers. - -Here is an example: -$ cat >foo <<EOF - %echo Generating a standard key - Key-Type: DSA - Key-Length: 1024 - Subkey-Type: ELG-E - Subkey-Length: 1024 - Name-Real: Joe Tester - Name-Comment: with stupid passphrase - Name-Email: joe@foo.bar - Expire-Date: 0 - Passphrase: abc - %pubring foo.pub - %secring foo.sec - # Do a commit here, so that we can later print "done" :-) - %commit - %echo done -EOF -$ gpg --batch --gen-key foo - [...] -$ gpg --no-default-keyring --secret-keyring ./foo.sec \ - --keyring ./foo.pub --list-secret-keys -/home/wk/work/gnupg-stable/scratch/foo.sec ------------------------------------------- -sec 1024D/915A878D 2000-03-09 Joe Tester (with stupid passphrase) <joe@foo.bar> -ssb 1024g/8F70E2C0 2000-03-09 - - - -Layout of the TrustDB -===================== -The TrustDB is built from fixed length records, where the first byte -describes the record type. All numeric values are stored in network -byte order. The length of each record is 40 bytes. The first record of -the DB is always of type 1 and this is the only record of this type. - -FIXME: The layout changed, document it here. - - Record type 0: - -------------- - Unused record, can be reused for any purpose. - - Record type 1: - -------------- - Version information for this TrustDB. This is always the first - record of the DB and the only one with type 1. - 1 byte value 1 - 3 bytes 'gpg' magic value - 1 byte Version of the TrustDB (2) - 1 byte marginals needed - 1 byte completes needed - 1 byte max_cert_depth - The three items are used to check whether the cached - validity value from the dir record can be used. - 1 u32 locked flags - 1 u32 timestamp of trustdb creation - 1 u32 timestamp of last modification which may affect the validity - of keys in the trustdb. This value is checked against the - validity timestamp in the dir records. - 1 u32 timestamp of last validation - (Used to keep track of the time, when this TrustDB was checked - against the pubring) - 1 u32 record number of keyhashtable - 1 u32 first free record - 1 u32 record number of shadow directory hash table - It does not make sense to combine this table with the key table - because the keyid is not in every case a part of the fingerprint. - 1 u32 record number of the trusthashtbale - - - Record type 2: (directory record) - -------------- - Informations about a public key certificate. - These are static values which are never changed without user interaction. - - 1 byte value 2 - 1 byte reserved - 1 u32 LID . (This is simply the record number of this record.) - 1 u32 List of key-records (the first one is the primary key) - 1 u32 List of uid-records - 1 u32 cache record - 1 byte ownertrust - 1 byte dirflag - 1 byte maximum validity of all the user ids - 1 u32 time of last validity check. - 1 u32 Must check when this time has been reached. - (0 = no check required) - - - Record type 3: (key record) - -------------- - Informations about a primary public key. - (This is mainly used to lookup a trust record) - - 1 byte value 3 - 1 byte reserved - 1 u32 LID - 1 u32 next - next key record - 7 bytes reserved - 1 byte keyflags - 1 byte pubkey algorithm - 1 byte length of the fingerprint (in bytes) - 20 bytes fingerprint of the public key - (This is the value we use to identify a key) - - Record type 4: (uid record) - -------------- - Informations about a userid - We do not store the userid but the hash value of the userid because that - is sufficient. - - 1 byte value 4 - 1 byte reserved - 1 u32 LID points to the directory record. - 1 u32 next next userid - 1 u32 pointer to preference record - 1 u32 siglist list of valid signatures - 1 byte uidflags - 1 byte validity of the key calculated over this user id - 20 bytes ripemd160 hash of the username. - - - Record type 5: (pref record) - -------------- - This record type is not anymore used. - - 1 byte value 5 - 1 byte reserved - 1 u32 LID; points to the directory record (and not to the uid record!). - (or 0 for standard preference record) - 1 u32 next - 30 byte preference data - - Record type 6 (sigrec) - ------------- - Used to keep track of key signatures. Self-signatures are not - stored. If a public key is not in the DB, the signature points to - a shadow dir record, which in turn has a list of records which - might be interested in this key (and the signature record here - is one). - - 1 byte value 6 - 1 byte reserved - 1 u32 LID points back to the dir record - 1 u32 next next sigrec of this uid or 0 to indicate the - last sigrec. - 6 times - 1 u32 Local_id of signatures dir or shadow dir record - 1 byte Flag: Bit 0 = checked: Bit 1 is valid (we have a real - directory record for this) - 1 = valid is set (but may be revoked) - - - - Record type 8: (shadow directory record) - -------------- - This record is used to reserve a LID for a public key. We - need this to create the sig records of other keys, even if we - do not yet have the public key of the signature. - This record (the record number to be more precise) will be reused - as the dir record when we import the real public key. - - 1 byte value 8 - 1 byte reserved - 1 u32 LID (This is simply the record number of this record.) - 2 u32 keyid - 1 byte pubkey algorithm - 3 byte reserved - 1 u32 hintlist A list of records which have references to - this key. This is used for fast access to - signature records which are not yet checked. - Note, that this is only a hint and the actual records - may not anymore hold signature records for that key - but that the code cares about this. - 18 byte reserved - - - - Record Type 10 (hash table) - -------------- - Due to the fact that we use fingerprints to lookup keys, we can - implement quick access by some simple hash methods, and avoid - the overhead of gdbm. A property of fingerprints is that they can be - used directly as hash values. (They can be considered as strong - random numbers.) - What we use is a dynamic multilevel architecture, which combines - hashtables, record lists, and linked lists. - - This record is a hashtable of 256 entries; a special property - is that all these records are stored consecutively to make one - big table. The hash value is simple the 1st, 2nd, ... byte of - the fingerprint (depending on the indirection level). - - When used to hash shadow directory records, a different table is used - and indexed by the keyid. - - 1 byte value 10 - 1 byte reserved - n u32 recnum; n depends on the record length: - n = (reclen-2)/4 which yields 9 for the current record length - of 40 bytes. - - the total number of such record which makes up the table is: - m = (256+n-1) / n - which is 29 for a record length of 40. - - To look up a key we use the first byte of the fingerprint to get - the recnum from this hashtable and look up the addressed record: - - If this record is another hashtable, we use 2nd byte - to index this hash table and so on. - - if this record is a hashlist, we walk all entries - until we found one a matching one. - - if this record is a key record, we compare the - fingerprint and to decide whether it is the requested key; - - - Record type 11 (hash list) - -------------- - see hash table for an explanation. - This is also used for other purposes. - - 1 byte value 11 - 1 byte reserved - 1 u32 next next hash list record - n times n = (reclen-5)/5 - 1 u32 recnum - - For the current record length of 40, n is 7 - - - - Record type 254 (free record) - --------------- - All these records form a linked list of unused records. - 1 byte value 254 - 1 byte reserved (0) - 1 u32 next_free - - - -Packet Headers -=============== - -GNUPG uses PGP 2 packet headers and also understands OpenPGP packet header. -There is one enhancement used with the old style packet headers: - - CTB bits 10, the "packet-length length bits", have values listed in - the following table: - - 00 - 1-byte packet-length field - 01 - 2-byte packet-length field - 10 - 4-byte packet-length field - 11 - no packet length supplied, unknown packet length - - As indicated in this table, depending on the packet-length length - bits, the remaining 1, 2, 4, or 0 bytes of the packet structure field - are a "packet-length field". The packet-length field is a whole - number field. The value of the packet-length field is defined to be - the value of the whole number field. - - A value of 11 is currently used in one place: on compressed data. - That is, a compressed data block currently looks like <A3 01 . . .>, - where <A3>, binary 10 1000 11, is an indefinite-length packet. The - proper interpretation is "until the end of the enclosing structure", - although it should never appear outermost (where the enclosing - structure is a file). - -+ This will be changed with another version, where the new meaning of -+ the value 11 (see below) will also take place. -+ -+ A value of 11 for other packets enables a special length encoding, -+ which is used in case, where the length of the following packet can -+ not be determined prior to writing the packet; especially this will -+ be used if large amounts of data are processed in filter mode. -+ -+ It works like this: After the CTB (with a length field of 11) a -+ marker field is used, which gives the length of the following datablock. -+ This is a simple 2 byte field (MSB first) containing the amount of data -+ following this field, not including this length field. After this datablock -+ another length field follows, which gives the size of the next datablock. -+ A value of 0 indicates the end of the packet. The maximum size of a -+ data block is limited to 65534, thereby reserving a value of 0xffff for -+ future extensions. These length markers must be inserted into the data -+ stream just before writing the data out. -+ -+ This 2 byte field is large enough, because the application must buffer -+ this amount of data to prepend the length marker before writing it out. -+ Data block sizes larger than about 32k doesn't make any sense. Note -+ that this may also be used for compressed data streams, but we must use -+ another packet version to tell the application that it can not assume, -+ that this is the last packet. - - -GNU extensions to the S2K algorithm -=================================== -S2K mode 101 is used to identify these extensions. -After the hash algorithm the 3 bytes "GNU" are used to make -clear that these are extensions for GNU, the next bytes gives the -GNU protection mode - 1000. Defined modes are: - 1001 - do not store the secret part at all - - -Usage of gdbm files for keyrings -================================ - The key to store the keyblock is its fingerprint, other records - are used for secondary keys. Fingerprints are always 20 bytes - where 16 bit fingerprints are appended with zero. - The first byte of the key gives some information on the type of the - key. - 1 = key is a 20 bit fingerprint (16 bytes fpr are padded with zeroes) - data is the keyblock - 2 = key is the complete 8 byte keyid - data is a list of 20 byte fingerprints - 3 = key is the short 4 byte keyid - data is a list of 20 byte fingerprints - 4 = key is the email address - data is a list of 20 byte fingerprints - - Data is prepended with a type byte: - 1 = keyblock - 2 = list of 20 byte padded fingerprints - 3 = list of list fingerprints (but how to we key them?) - - - -Pipemode -======== -This mode can be used to perform multiple operations with one call to -gpg. It comes handy in cases where you have to verify a lot of -signatures. Currently we support only detached signatures. This mode -is a kludge to avoid running gpg n daemon mode and using Unix Domain -Sockets to pass the data to it. There is no easy portable way to do -this under Windows, so we use plain old pipes which do work well under -Windows. Because there is no way to signal multiple EOFs in a pipe we -have to embed control commands in the data stream: We distinguish -between a data state and a control state. Initially the system is in -data state but it won't accept any data. Instead it waits for -transition to control state which is done by sending a single '@' -character. While in control state the control command os expected and -this command is just a single byte after which the system falls back -to data state (but does not necesary accept data now). The simplest -control command is a '@' which just inserts this character into the -data stream. - -Here is the format we use for detached signatures: -"@<" - Begin of new stream -"@B" - Detached signature follows. - This emits a control packet (1,'B') -<detached_signature> -"@t" - Signed text follows. - This emits the control packet (2, 'B') -<signed_text> -"@." - End of operation. The final control packet forces signature - verification -"@>" - End of stream - - - - - - -Other Notes -=========== - * For packet version 3 we calculate the keyids this way: - RSA := low 64 bits of n - ELGAMAL := build a v3 pubkey packet (with CTB 0x99) and calculate - a rmd160 hash value from it. This is used as the - fingerprint and the low 64 bits are the keyid. - - * Revocation certificates consist only of the signature packet; - "import" knows how to handle this. The rationale behind it is - to keep them small. - - - - - - - -Keyserver Message Format -========================= - -The keyserver may be contacted by a Unix Domain socket or via TCP. - -The format of a request is: - -==== -command-tag -"Content-length:" digits -CRLF -======= - -Where command-tag is - -NOOP -GET <user-name> -PUT -DELETE <user-name> - - -The format of a response is: - -====== -"GNUPG/1.0" status-code status-text -"Content-length:" digits -CRLF -============ -followed by <digits> bytes of data - - -Status codes are: - - o 1xx: Informational - Request received, continuing process - - o 2xx: Success - The action was successfully received, understood, - and accepted - - o 4xx: Client Error - The request contains bad syntax or cannot be - fulfilled - - o 5xx: Server Error - The server failed to fulfill an apparently - valid request - - - -Documentation on HKP (the http keyserver protocol): - -A minimalistic HTTP server on port 11371 recognizes a GET for /pks/lookup. -The standard http URL encoded query parameters are this (always key=value): - -- op=index (like pgp -kv), op=vindex (like pgp -kvv) and op=get (like - pgp -kxa) - -- search=<stringlist>. This is a list of words that must occur in the key. - The words are delimited with space, points, @ and so on. The delimiters - are not searched for and the order of the words doesn't matter (but see - next option). - -- exact=on. This switch tells the hkp server to only report exact matching - keys back. In this case the order and the "delimiters" are important. - -- fingerprint=on. Also reports the fingerprints when used with 'index' or - 'vindex' - -The keyserver also recognizes http-POSTs to /pks/add. Use this to upload -keys. - - -A better way to do this would be a request like: - - /pks/lookup/<gnupg_formatierte_user_id>?op=<operation> - -This can be implemented using Hurd's translator mechanism. -However, I think the whole key server stuff has to be re-thought; -I have some ideas and probably create a white paper. - |