Testing the exit status

Werner Koch wk at gnupg.org
Mon Oct 12 19:22:28 CEST 2009

On Mon, 12 Oct 2009 17:46, David.Gray at turpin-distribution.com said:

> Thanks for the info.  I'm still not clear on how to use the argument
> "status-fd 2"

Writing to a file descriptor is basic technique on almost all systems.
You may want to consult the APUE [1] to see how it works.

> I originally opened the file doc/DETAILS with notepad but it was quite
> unreadable. 

I have no problems to read it; see below




                                                              -*- text -*-
Format of colon listings
First an example:

$ gpg --fixed-list-mode --with-colons --list-keys \
   --with-fingerprint --with-fingerprint wk at gnupg.org

uid:f::::::::Werner Koch <wk at g10code.com>:
uid:f::::::::Werner Koch <wk at gnupg.org>:

The double --with-fingerprint prints the fingerprint for the subkeys
too. --fixed-list-mode is the modern listing way printing dates in
seconds since Epoch and does not merge the first userID with the pub
record; gpg2 does this by default and the option is a dummy.

 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
            tru = trust database information
            spk = signature subpacket

 2. Field:  A letter describing the calculated validity. 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
		    (deprecated - use the 'D' in field 12 instead)
		r = The key has been revoked
		e = The key has expired
		- = Unknown validity (i.e. no value assigned)
		q = Undefined validity
	            '-' and 'q' may safely be treated as the same
		    value for most purposes
		n = The key is valid
		m = The key is marginal valid.
		f = The key is fully valid
		u = The key is ultimately valid.  This often means
		    that the secret key is available, but any key may
		    be marked as ultimately valid. 

            If the validity information is given for a UID or UAT
            record, it describes the validity calculated based on this
            user ID.  If given for a key record it describes the best
            validity taken from the best rated user ID.

            For X.509 certificates a 'u' is used for a trusted root
            certificate (i.e. for the trust anchor) and an 'f' for all
            other valid certificates.

 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 - don't use them!)
	    (for other id's see include/cipher.h)

 5. Field:  KeyID

 6. Field:  Creation Date (in UTC).  For UID and UAT records, this is
            the self-signature date.  Note that the date is usally
            printed in seconds since epoch, however, we are migrating
            to an ISO 8601 format (e.g. "19660205T091500").  This is
            currently only relevant for X.509.  A simple way to detect
            the new format is to scan for the 'T'.

 7. Field:  Key or user ID/user attribute expiration date or empty if none.

 8. Field:  Used for serial number in crt records (used to be the Local-ID).
            For UID and UAT records, this is a hash of the user ID contents
            used to represent that exact user ID.  For trust signatures,
            this is the trust depth seperated by the trust value by a

 9. Field:  Ownertrust (primary public keys only)
	    This is a single letter, but be prepared that additional
	    information may follow in some future versions.  For trust
	    signatures with a regular expression, this is the regular
	    expression value, quoted as in field 10. 

10. Field:  User-ID.  The value is quoted like a C string to avoid
	    control characters (the colon is quoted "\x3a").
            For a "pub" record this field is not used on --fixed-list-mode.
            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 as per RFC-4880.  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' is used the same way.  IT is not
            used for X.509.

12. Field:  Key capabilities:
                e = encrypt
                s = sign
                c = certify
                a = authentication
	    A key may have any combination of them in any order.  In
	    addition to these letters, the primary key has uppercase
	    versions of the letters to denote the _usable_
	    capabilities of the entire key, and a potential letter 'D'
	    to indicate a disabled 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 issuer
            certificate is available. The root has been reached if
            this is the same string as the fingerprint. 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" records this lists the preferences in the same 
            way the gpg's --edit-key menu does.
	    For "sig" records, this is the fingerprint of the key that
	    issued the signature.  Note that this is only filled in if
	    the signature verified correctly.  Note also that for
	    various technical reasons, this fingerprint is only
	    available if --no-sig-cache is used.

14. Field   Flag field used in the --edit menu output:

15. Field   Used in sec/sbb to print the serial number of a token
            (internal protect mode 1002) or a '#' if that key is a
            simple stub (internal protect mode 1001)

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

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)

Example for a "tru" trust base record:


 The fields are:

 2: Reason for staleness of trust.  If this field is empty, then the
    trustdb is not stale.  This field may have multiple flags in it:

    o: Trustdb is old
    t: Trustdb was built with a different trust model than the one we
       are using now.

 3: Trust model:
    0: Classic trust model, as used in PGP 2.x.
    1: PGP trust model, as used in PGP 6 and later.  This is the same
       as the classic trust model, except for the addition of trust

    GnuPG before version 1.4 used the classic trust model by default.
    GnuPG 1.4 and later uses the PGP trust model by default.

 4: Date trustdb was created in seconds since 1970-01-01.
 5: Date trustdb will expire in seconds since 1970-01-01.
 6: Number of marginally trusted users to introduce a new key signer
    (gpg's option --marginals-needed)
 7: Number of completely trusted users to introduce a new key signer.
    (gpg's option --completes-needed)
 8: Maximum depth of a certification chain.  
    *gpg's option --max-cert-depth)

The "spk" signature subpacket records have the fields:

 2: Subpacket number as per RFC-4880 and later.
 3: Flags in hex.  Currently the only two bits assigned are 1, to
    indicate that the subpacket came from the hashed part of the
    signature, and 2, to indicate the subpacket was marked critical.
 4: Length of the subpacket.  Note that this is the length of the
    subpacket, and not the length of field 5 below.  Due to the need
    for %-encoding, the length of field 5 may be up to 3x this value.
 5: The subpacket data.  Printable ASCII is shown as ASCII, but other
    values are rendered as %XX where XX is the hex value for the byte.

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.

        May be issued right before a signature verification starts.  This
        is useful to define a context for parsing ERROR status
        messages.  No arguments are currently defined.

    GOODSIG  <long_keyid_or_fpr>  <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. The fingerprint may be used instead of the long keyid
        if it is available.  This is the case with CMS and might
        eventually also be available for OpenPGP.

    EXPSIG  <long_keyid_or_fpr>  <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. The fingerprint may be used instead of the long
	keyid if it is available.  This is the case with CMS and might
	eventually also be available for OpenPGP.

    EXPKEYSIG  <long_keyid_or_fpr> <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.  The fingerprint may be used
	instead of the long keyid if it is available.  This is the
	case with CMS and might eventually also be available for

    REVKEYSIG  <long_keyid_or_fpr>  <username>
	The signature with the keyid is good, but the signature was
	made by a revoked key. The username is the primary one encoded
	in UTF-8 and %XX escaped. The fingerprint may be used instead
	of the long keyid if it is available.  This is the case with
	CMS and might eventually also be available for OpenPGP.

    BADSIG  <long_keyid_or_fpr>  <username>
	The signature with the keyid has not been verified okay.  The
        username is the primary one encoded in UTF-8 and %XX
        escaped. The fingerprint may be used instead of the long keyid
        if it is available.  This is the case with CMS and might
        eventually also be available for OpenPGP.

    ERRSIG  <long_keyid_or_fpr>  <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.  The fingerprint
	may be used instead of the long keyid if it is available.
	This is the case with CMS and might eventually also be
	available for OpenPGP.

        Note, that TIMESTAMP may either be a number with seconds since
        epoch or an ISO 8601 string which can be detected by the
        presence of the letter 'T' inside.

    VALIDSIG	<fingerprint in hex> <sig_creation_date> <sig-timestamp>
		<expire-timestamp>  <sig-version> <reserved> <pubkey-algo>
		<hash-algo> <sig-class> [ <primary-key-fpr> ]

	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.  All arguments here
	are on one long line.  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-version, pubkey-algo, hash-algo,
	and sig-class (a 2-byte hex value) are all straight from the
	signature packet.  PRIMARY-KEY-FPR is the fingerprint of the
	primary key or identical to the first argument.  This is
	useful to get back to the primary key without running gpg
	again for this purpose.

        The primary-key-fpr parameter is used for OpenPGP and not
        available for CMS signatures.  The sig-version as well as the
        sig class is not defined for CMS and currently set to 0 and 00.

        Note, that *-TIMESTAMP may either be a number with seconds
        since epoch or an ISO 8601 string which can be detected by the
        presence of the letter 'T' inside.

    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.

        Note, that SIG-TIMESTAMP may either be a number with seconds
        since epoch or an ISO 8601 string which can be detected by the
        presence of the letter 'T' inside.

    ENC_TO  <long_keyid>  <keytype>  <keylength>
	The message is encrypted to this LONG_KEYID.  KEYTYPE is the
	numerical value of the public key algorithm or 0 if it is not
	known, KEYLENGTH is the length of the key or 0 if it is not
	known (which is currently always the case).  Gpg prints this
	line always; Gpgsm only if it knows the certificate.

    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
            4 - signature expected but not found
	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  [0  [<validation_model>]]
    TRUST_FULLY     [0  [<validation_model>]] 
    TRUST_ULTIMATE  [0  [<validation_model>]]
	For good signatures one of these status lines are emitted to
	indicate the validity of the key used to create the signature.
	The error token values are currently only emitted by gpgsm.
	VALIDATION_MODEL describes the algorithm used to check the
	validity of the key.  The defaults are the standard Web of
	Trust model for gpg and the the standard X.509 model for
	gpgsm.  The defined values are

           "pgp"   for the standard PGP WoT.
	   "shell" for the standard X.509 model.
	   "chain" for the chain model.

        Note that we use the term "TRUST_" in the status names for
        historic reasons; we now speak of validity.

    PKA_TRUST_GOOD <mailbox>
    PKA_TRUST_BAD  <mailbox>
        Depending on the outcome of the PKA check one of the above
        status codes is emitted in addition to a TRUST_* status.
        Without PKA info available or 

	This is deprecated in favor of KEYEXPIRED.

    KEYEXPIRED <expire-timestamp>
	The key has expired.  expire-timestamp is the expiration time
	in seconds since Epoch.  This status line is not very useful
	because it will also be emitted for expired subkeys even if
	this subkey is not used.  To check whether a key used to sign
	a message has expired, the EXPKEYSIG status line is to be

        Note, that TIMESTAMP may either be a number with seconds since
        epoch or an ISO 8601 string which can be detected by the
        presence of the letter 'T' inside.

	The used key has been revoked by its owner.  No arguments yet.

	The ASCII armor is corrupted.  No arguments yet.

	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.



    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.

    NEED_PASSPHRASE_PIN <card_type> <chvno> [<serialno>]
        Issued whenever a PIN is requested to unlock a card.

	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 <long keyid>
	The supplied passphrase was wrong or not given.  In the latter case
	you may have seen a MISSING_PASSPHRASE.

	The supplied passphrase was good and the secret key material
	is therefore usable.

	The symmetric decryption failed - one reason could be a wrong
	passphrase for a symmetrical encrypted message.

	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

    IMPORT_CHECK <long keyid> <fingerprint> <user ID>
        This status is emitted in interactive mode right before
        the "import.okay" prompt.

    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
	    1 - verify
            2 - encrypt
            3 - decrypt        

	Marks the end of a file processing which has been started

	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>
	Mark the start and end of the actual encryption process.

       Mark the start of the actual signing process. This may be used
       as an indication that all requested secret keys are ready for

    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.	The condition 
           TOATL && CUR == TOTAL
        may be used to detect the end of an operation.
        Well known values for WHAT:
             "pk_dsa"   - DSA key generation
             "pk_elg"   - Elgamal key generation
             "primegen" - Prime generation
             "need_entropy" - Waiting for new entropy in the RNG
             "file:XXX" - processing file XXX
                          (note that current gpg versions leave out the
                           "file:" prefix).
             "tick"     - generic tick without any special meaning - useful
                          for letting clients know that the server is
                          still working.
             "starting_agent" - A gpg-agent was started because it is not
                          running as a daemon.
             "learncard"  Send by the agent and gpgsm while learing
	                  the data of a smartcard.
             "card_busy"  A smartcard is still working
    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

        Note, that TIMESTAMP may either be a number with seconds since
        epoch or an ISO 8601 string which can be detected by the
        presence of the letter 'T' inside.
    KEY_CREATED <type> <fingerprint> [<handle>]
        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.  Handle is an arbitrary
        non-whitespace string used to match key parameters from batch
        key creation run.

    KEY_NOT_CREATED [<handle>]
        The key from batch run has not been created due to errors.

    SESSION_KEY  <algo>:<hexdigits>
	The session key used to decrypt the message.  This message will
	only be emitted when the special option --show-session-key
	is used.  The format is suitable to be passed to the option

    NOTATION_NAME <name> 
    NOTATION_DATA <string>
        name and string are %XX escaped; the data may be split
        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

        Issued by pipemode.

    INV_RECP <reason> <requested_recipient>
    INV_SGNR <reason> <requested_sender>
        Issued for each unusable recipient/sender. 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"
         11 := "Missing certificate"  (e.g. intermediate or root cert.)

        Note that for historical reasons the INV_RECP status is also
        used for gpgsm's SIGNER command where it relates to signer's
        of course.  Newer GnuPG versions are using INV_SGNR;
        applications should ignore the INV_RECP during the sender's
        command processing once they have seen an INV_SGNR.  We use
        different code so that we can distinguish them while doing an

    NO_RECP <reserved>
    NO_SGNR <reserved>
        Issued when no recipients/senders 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> [<more>]

        This is a generic error status message, it might be followed
        by error location specific data. <error code> and
        <error_location> should not contain spaces.  The error code is
        a either a string commencing with a letter or such a string
        prefixed with a numerical error code and an underscore; e.g.:

    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

    CARDCTRL <what> [<serialno>]
        This is used to control smartcard operations.
        Defined values for WHAT are:
           1 = Request insertion of a card.  Serialnumber may be given
               to request a specific card.  Used by gpg 1.4 w/o scdaemon.
           2 = Request removal of a card.  Used by gpg 1.4 w/o scdaemon.
           3 = Card with serialnumber detected
           4 = No card available.
           5 = No card reader available
           6 = No card support available                      

    PLAINTEXT <format> <timestamp> <filename>
        This indicates the format of the plaintext that is about to be
        written.  The format is a 1 byte hex code that shows the
        format of the plaintext: 62 ('b') is binary data, 74 ('t') is
        text data with no character set specified, and 75 ('u') is
        text data encoded in the UTF-8 character set.  The timestamp
        is in seconds since the epoch.  If a filename is available it
        gets printed as the third argument, percent-escaped as usual.

        This indicates the length of the plaintext that is about to be
        written.  Note that if the plaintext packet has partial length
        encoding it is not possible to know the length ahead of time.
        In that case, this status tag does not appear.

    SIG_SUBPACKET <type> <flags> <len> <data>
        This indicates that a signature subpacket was seen.  The
        format is the same as the "spk" record above.

    SC_OP_FAILURE [<code>]
        An operation on a smartcard definitely failed.  Currently
        there is no indication of the actual error code, but
        application should be prepared to later accept more arguments.
        Defined values for CODE are:
           0 - unspecified error (identically to a missing CODE)
           1 - canceled
           2 - bad PIN

        A smart card operaion succeeded.  This status is only printed
        for certain operation and is mostly useful to check whether a
        PIN change really worked.

    BACKUP_KEY_CREATED fingerprint fname
        A backup key named FNAME has been created for the key with

Format of the "--attribute-fd" output

When --attribute-fd is set, during key listings (--list-keys,
--list-secret-keys) GnuPG dumps each attribute packet to the file
descriptor specified.  --attribute-fd is intended for use with
--status-fd as part of the required information is carried on the
ATTRIBUTE status tag (see above).

The contents of the attribute data is specified by RFC 4880.  For
convenience, here is the Photo ID format, as it is currently the only
attribute defined:

   Byte 0-1:  The length of the image header.  Due to a historical
              accident (i.e. oops!) back in the NAI PGP days, this is
              a little-endian number.  Currently 16 (0x10 0x00).

   Byte 2:    The image header version.  Currently 0x01.

   Byte 3:    Encoding format.  0x01 == JPEG.

   Byte 4-15: Reserved, and currently unused.

   All other data after this header is raw image (JPEG) data.

Format of the "--list-config" output

--list-config outputs information about the GnuPG configuration for
the benefit of frontends or other programs that call GnuPG.  There are
several list-config items, all colon delimited like the rest of the
--with-colons output.  The first field is always "cfg" to indicate
configuration information.  The second field is one of (with

version: the third field contains the version of GnuPG.


pubkey: the third field contains the public key algorithmdcaiphers
	this version of GnuPG supports, separated by semicolons.  The
	algorithm numbers are as specified in RFC-4880.


cipher: the third field contains the symmetric ciphers this version of
	GnuPG supports, separated by semicolons.  The cipher numbers
	are as specified in RFC-4880.


digest: the third field contains the digest (hash) algorithms this
	version of GnuPG supports, separated by semicolons.  The
	digest numbers are as specified in RFC-4880.


compress: the third field contains the compression algorithms this
	  version of GnuPG supports, separated by semicolons.  The
	  algorithm numbers are as specified in RFC-4880.


group: the third field contains the name of the group, and the fourth
       field contains the values that the group expands to, separated
       by semicolons.

For example, a group of:
   group mynames = paige 0x12345678 joe patti

would result in:

Key generation
    See the Libcrypt manual.

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>.
	Suppress actual key generation (useful for syntax checking).
	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.
        Enable a mode where the command "passphrase" is ignored and
        instead the usual passphrase dialog is used.  This does not
        make sense for batch key generation; however the unattended
        key generation feature is also used by GUIs and this feature
        relinquishes the GUI from implementing its own passphrase
        entry code.  This is a global option.
        Disable the ask-passphrase mode.        

   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", "sign", and "auth".  This is used to generate the
        key flags.  Please make sure that the algorithm is capable of
        this usage.  Note that OpenPGP requires that all primary keys
        are capable of certification, so no matter what usage is given
        here, the "cert" flag will be on.  If no Key-Usage is
        specified, all the allowed usages for that particular
        algorithm are used.
     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.  The special notation
	"seconds=N" is also allowed to directly give an Epoch
	value. Without a letter days are assumed.  Note that there is
	no check done on the overflow of the type used by OpenPGP for
	timestamps.  Thus you better make sure that the given value
	make sense.  Although OpenPGP works with time intervals, GnuPG
	uses an absolute value internally and thus the last year we
	can represent is 2105.
     Creation-Date: <iso-date>
        Set the creation date of the key as stored in the key
        information and which is also part of the fingerprint
        calculation.  Either a date like "1986-04-26" or a full
        timestamp like "19860426T042640" may be used.  The time is
        considered to be UTC.  If it is not given the current time 
        is used.
     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.
     Handle: <string>
        This is an optional parameter only used with the status lines
        KEY_CREATED and KEY_NOT_CREATED.  STRING may be up to 100
        characters and should not contain spaces.  It is useful for
        batch key generation to associate a key parameter block with a
        status line.
     Keyserver: <string>
        This is an optional parameter that specifies the preferred
        keyserver URL for the key.

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 at foo.bar
     Expire-Date: 0
     Passphrase: abc
     %pubring foo.pub
     %secring foo.sec
     # Do a commit here, so that we can later print "done" :-)
     %echo done
$ gpg --batch --gen-key foo
$ gpg --no-default-keyring --secret-keyring ./foo.sec \
				  --keyring ./foo.pub --list-secret-keys
sec  1024D/915A878D 2000-03-09 Joe Tester (with stupid passphrase) <joe at 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 [not used]
     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 [currently not used]
	    (Used to keep track of the time, when this TrustDB was checked
	     against the pubring)
     1 u32  record number of keyhashtable [currently not used]
     1 u32  first free record
     1 u32  record number of shadow directory hash table [currently not used]
	    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

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
  1002 - a stub to access smartcards (not used in 1.2.x)

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.

OIDs below the GnuPG arc:
=========================          GnuPG          notation          pkaAddress   invalid encoded OID

Keyserver Message Format

The keyserver may be contacted by a Unix Domain socket or via TCP.

The format of a request is:

"Content-length:" digits

Where command-tag is

GET <user-name>
DELETE <user-name>

The format of a response is:

"GNUPG/1.0" status-code status-text
"Content-length:" digits
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

     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

The keyserver also recognizes http-POSTs to /pks/add. Use this to upload

A better way to do this would be a request like:


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.

Die Gedanken sind frei.  Auschnahme regelt ein Bundeschgesetz.

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