mirror of
git://git.gnupg.org/gnupg.git
synced 2024-11-10 21:38:50 +01:00
41862f5f13
(show_file): Implement it. * keyformat.txt: Define the created-at attribute for keys. * ccid-driver.c: Replaced macro DEBUG_T1 by a new debug level. (parse_ccid_descriptor): Mark SCR335 firmware version 5.18 good. (ccid_transceive): Arghhh. The seqno is another bit in the R-block than in the I block, this was wrong at one place. * scdaemon.c: New options --debug-ccid-driver and --debug-disable-ticker. * app-openpgp.c (do_genkey, do_writekey): Factored code to check for existing key out into .. (does_key_exist): .. New function. * gpg-connect-agent.c (add_definq, show_definq, clear_definq) (handle_inquire): New. (read_and_print_response): Handle INQUIRE command. (main): Implement control commands.
175 lines
5.1 KiB
Plaintext
175 lines
5.1 KiB
Plaintext
keyformat.txt (wk 2001-12-18)
|
|
-----------------------------
|
|
|
|
|
|
Some notes on the format of the secret keys used with gpg-agent.
|
|
|
|
Location of keys
|
|
================
|
|
The secret keys[1] are stored on a per file basis in a directory below
|
|
the ~/.gnupg home directory. This directory is named
|
|
|
|
private-keys-v1.d
|
|
|
|
and should have permissions 700.
|
|
|
|
The secret keys are stored in files with a name matching the
|
|
hexadecimal representation of the keygrip[2].
|
|
|
|
Unprotected Private Key Format
|
|
==============================
|
|
The content of the file is an S-Expression like the ones used with
|
|
Libgcrypt. Here is an example of an unprotected file:
|
|
|
|
(private-key
|
|
(rsa
|
|
(n #00e0ce9..[some bytes not shown]..51#)
|
|
(e #010001#)
|
|
(d #046129F..[some bytes not shown]..81#)
|
|
(p #00e861b..[some bytes not shown]..f1#)
|
|
(q #00f7a7c..[some bytes not shown]..61#)
|
|
(u #304559a..[some bytes not shown]..9b#)
|
|
)
|
|
(created-at timestamp)
|
|
(uri http://foo.bar x-foo:whatever_you_want)
|
|
(comment whatever)
|
|
)
|
|
|
|
"comment", "created-at" and "uri" are optional. "comment" is
|
|
currently used to keep track of ssh key comments. "created-at" is used
|
|
to keep track of the creation time stamp used with OpenPGP keys; it is
|
|
optional but required for some operations to calculate the fingerprint
|
|
of the key. This timestamp should be a string with the number of
|
|
seconds since Epoch or an ISO time string (yyyymmddThhmmss).
|
|
|
|
Actually this form should not be used for regular purposes and only
|
|
accepted by gpg-agent with the configuration option:
|
|
--allow-non-canonical-key-format. The regular way to represent the
|
|
keys is in canonical representation[3]:
|
|
|
|
(private-key
|
|
(rsa
|
|
(n #00e0ce9..[some bytes not shown]..51#)
|
|
(e #010001#)
|
|
(d #046129F..[some bytes not shown]..81#)
|
|
(p #00e861b..[some bytes not shown]..f1#)
|
|
(q #00f7a7c..[some bytes not shown]..61#)
|
|
(u #304559a..[some bytes not shown]..9b#)
|
|
)
|
|
(uri http://foo.bar x-foo:whatever_you_want)
|
|
)
|
|
|
|
|
|
Protected Private Key Format
|
|
==============================
|
|
A protected key is like this:
|
|
|
|
(protected-private-key
|
|
(rsa
|
|
(n #00e0ce9..[some bytes not shown]..51#)
|
|
(e #010001#)
|
|
(protected mode (parms) encrypted_octet_string)
|
|
)
|
|
(uri http://foo.bar x-foo:whatever_you_want)
|
|
(comment whatever)
|
|
)
|
|
|
|
|
|
In this scheme the encrypted_octet_string is encrypted according to
|
|
the algorithm described after the keyword protected; most protection
|
|
algorithms need some parameters, which are given in a list before the
|
|
encrypted_octet_string. The result of the decryption process is a
|
|
list of the secret key parameters.
|
|
|
|
The only available protection mode for now is
|
|
|
|
openpgp-s2k3-sha1-aes-cbc
|
|
|
|
which describes an algorithm using using AES in CBC mode for
|
|
encryption, SHA-1 for integrity protection and the String to Key
|
|
algorithm 3 from OpenPGP (rfc2440).
|
|
|
|
Example:
|
|
|
|
(protected openpgp-s2k3-sha1-aes-cbc
|
|
((sha1 16byte_salt no_of_iterations) 16byte_iv)
|
|
encrypted_octet_string
|
|
)
|
|
|
|
The encrypted_octet string should yield this S-Exp (in canonical
|
|
representation) after decryption:
|
|
|
|
(
|
|
(
|
|
(d #046129F..[some bytes not shown]..81#)
|
|
(p #00e861b..[some bytes not shown]..f1#)
|
|
(q #00f7a7c..[some bytes not shown]..61#)
|
|
(u #304559a..[some bytes not shown]..9b#)
|
|
)
|
|
(hash sha1 #...[hashvalue]...#)
|
|
)
|
|
|
|
For padding reasons, random bytes are appended to this list - they can
|
|
easily be stripped by looking for the end of the list.
|
|
|
|
The hash is calculated on the concatenation of the public key and
|
|
secret key parameter lists: i.e it is required to hash the
|
|
concatenation of these 6 canonical encoded lists for RSA, including
|
|
the parenthesis and the algorithm keyword.
|
|
|
|
(rsa
|
|
(n #00e0ce9..[some bytes not shown]..51#)
|
|
(e #010001#)
|
|
(d #046129F..[some bytes not shown]..81#)
|
|
(p #00e861b..[some bytes not shown]..f1#)
|
|
(q #00f7a7c..[some bytes not shown]..61#)
|
|
(u #304559a..[some bytes not shown]..9b#)
|
|
)
|
|
|
|
After decryption the hash must be recalculated and compared against
|
|
the stored one - If they don't match the integrity of the key is not
|
|
given.
|
|
|
|
|
|
Shadowed Private Key Format
|
|
============================
|
|
To keep track of keys stored on IC cards we use a third format for
|
|
private kyes which are called shadow keys as they are only a reference
|
|
to keys stored on a token:
|
|
|
|
(shadowed-private-key
|
|
(rsa
|
|
(n #00e0ce9..[some bytes not shown]..51#)
|
|
(e #010001#)
|
|
(shadowed protocol (info))
|
|
)
|
|
(uri http://foo.bar x-foo:whatever_you_want)
|
|
(comment whatever)
|
|
)
|
|
|
|
The currently used protocol is "ti-v1" (token info version 1). The
|
|
second list with the information has this layout:
|
|
|
|
(card_serial_number id_string_of_key)
|
|
|
|
More items may be added to the list.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Notes:
|
|
======
|
|
[1] I usually use the terms private and secret key exchangeable but prefer the
|
|
term secret key because it can be visually be better distinguished
|
|
from the term public key.
|
|
|
|
[2] The keygrip is a unique identifier for a key pair, it is
|
|
independent of any protocol, so that the same key can be used with
|
|
different protocols. PKCS-15 calls this a subjectKeyHash; it can be
|
|
calculated using Libgcrypt's gcry_pk_get_keygrip ().
|
|
|
|
[3] Even when canonical representation are required we will show the
|
|
S-expression here in a more readable representation.
|