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gnupg/doc/DETAILS
Werner Koch 0de9aedf3e
doc: Replace "conventional encryption" by "symmetric encryption". 
--

Suggested-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
2015-06-02 17:47:10 +02:00

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-*- text -*-
Format of colon listings
========================
First an example:
$ gpg --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 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 = keygrip
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r = The key has been revoked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
space.
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)
16. Field: For sig records, this is the used hash algorithm:
2 = SHA-1
8 = SHA-256
(for other id's see include/cipher.h)
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)
Example for a "tru" trust base record:
tru:o:0:1166697654:1:3:1:5
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
signatures.
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.
NEWSIG
Is 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 codes GOODSIG, BADSIG, EXPSIG, EXPKEYSIG, REVKEYSIG
or ERRSIG will be emitted. In the past they were used as a
marker for a new signature; new code should use the NEWSIG
status instead. 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
OpenPGP.
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
message.
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
SIGEXPIRED
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
used.
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.
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.
NEED_PASSPHRASE_PIN <card_type> <chvno> [<serialno>]
Issued whenever a PIN is requested to unlock a card.
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 symmetric with passphrase 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> <skipped_new_keys> <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.
BEGIN_SIGNING
Mark the start of the actual signing process. This may be used
as an indication that all requested secret keys are ready for
use.
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
--override-session-key
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
BEGIN_STREAM
END_STREAM
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"
12 := "Missing issuer certificate"
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
encrypt+sign.
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.:
"151011327_EOF".
SUCCESS [<location>]
Postive confirimation that an operation succeeded. <location>
is optional but if given should not contain spaces.
Used only with a few commands.
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.
PLAINTEXT_LENGTH <length>
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
SC_OP_SUCCESS
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
KEYID.
MOUNTPOINT <name>
NAME is a percent-plus escaped filename describing the
mountpoint for the current operation (e.g. g13 --mount). This
may either be the specified mountpoint or one randomly choosen
by g13.
DECRYPTION_INFO <mdc_method> <sym_algo>
Print information about the symmetric encryption algorithm and
the MDC method. This will be emitted even if the decryption
fails.
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
examples):
version: the third field contains the version of GnuPG.
cfg:version:1.3.5
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. Note that in
contrast to the --status-fd interface these are _not_ the
Libgcrypt identifiers.
cfg:pubkey:1;2;3;16;17
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.
cfg:cipher:2;3;4;7;8;9;10
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.
cfg:digest:1;2;3;8;9;10
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.
cfg:compress:0;1;2;3
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:
cfg:group:mynames:patti;joe;0x12345678;paige
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>.
%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).
GnuPG < 2.1: Both control statements must be given.
GnuPG >= 2.1: "%secring" is now a no-op.
%ask-passphrase
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.
%no-ask-passphrase
Disable the ask-passphrase mode.
%no-protection
With GnuPG 2.1 it is not anymore possible to specify a
passphrase for unattended key generation. The passphrase
command is simply ignored and %ask-passpharse is thus
implicitly enabled. Using this option allows to the creation
of keys without any passphrases. This option is mainly
intended for regression tests.
%transient-key
If given the keys are created using a faster and a somewhat
less secure random number generator. This option may be used
for keys which are only used for a short time and do not
require full cryptographic strength. It takes only effect if
used together with the option no-protection.
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. It may be "default" to use the default
one; in this case don't give a Key-Usage and use "default" for
the Subkey-Type.
Key-Length: <length-in-bits>
Length of the key in bits. The default is returned by running
the command "gpg --gpgconf-list".
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 and the key-type is not "default", all allowed
usages for that particular algorithm are used; if it is not
given but "default" is used the usage will be "sign".
Subkey-Type: <algo-number>|<algo-string>
This generates a secondary key. Currently only one subkey
can be handled. "default" is also supported.
Subkey-Length: <length-in-bits>
Length of the subkey in bits. The default is returned by running
the command "gpg --gpgconf-list".
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 on how to create a key:
$ cat >foo <<EOF
%echo Generating a basic OpenPGP 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
If you want to create a key with the default algorithms you would
use these parameters:
%echo Generating a default key
Key-Type: default
Subkey-Type: default
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
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:
=========================
1.3.6.1.4.1.11591.2 GnuPG
1.3.6.1.4.1.11591.2.1 notation
1.3.6.1.4.1.11591.2.1.1 pkaAddress
1.3.6.1.4.1.11591.2.12242973 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:
====
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.
Algorithm names for the "keygen.algo" prompt
============================================
When using a --command-fd controlled key generation or "addkey"
there is way to know the number to enter on the "keygen.algo"
prompt. The displayed numbers are for human reception and may
change with releases. To provide a stable way to enter a desired
algorithm choice the prompt also accepts predefined names for the
algorithms, which will not change.
| Name | No | Description |
|---------+----+---------------------------------|
| rsa+rsa | 1 | RSA and RSA (default) |
| dsa+elg | 2 | DSA and Elgamal |
| dsa | 3 | DSA (sign only) |
| rsa/s | 4 | RSA (sign only) |
| elg | 5 | Elgamal (encrypt only) |
| rsa/e | 6 | RSA (encrypt only) |
| dsa/* | 7 | DSA (set your own capabilities) |
| rsa/* | 8 | RSA (set your own capabilities) |
If one of the "foo/*" names are used a "keygen.flags" prompt needs
to be answered as well. Instead of toggling the predefined flags,
it is also possible to set them direct: Use a "=" character
directly followed by a comination of "a" (for authentication), "s"
(for signing), or "c" (for certification).
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