KEYTEXT(6) KEYTEXT(6)
NAME
keytext - textual form of Inferno public/private keys
DESCRIPTION
Keyring-certtostr(2) defines a set of functions that convert
between textual forms of the elements of the Inferno
public-key authentication system and their internal data
types. The textual form is used for key storage and as the
transport format for the authentication protocol auth(6). In
storage and transport each encoded value is encapsulated by
the record-oriented encoding defined in keyring-getmsg(2).
The format represents public and private keys, and signer's
certificates. In this context a certificate is a time-
limited cryptographically signed hash of some other value
(usually a public key) and contains neither that value nor
the signer's key, which is assumed to be available else-
where.
All values are represented by a sequence of newline-
separated text fields. The type of any given value is
determined by its context. Each type of value has a common
prefix that includes an algorithm identifier, followed by a
sequence of algorithm-dependent fields:
authinfo ::= signer-public-key certificate
!private-key big-alpha big-p
certificate ::= sigalg hashalg signer-name
exp-time *-sig
sigalg ::= rsa | dsa | elgamal
hashalg ::= sha1 | md5
*-key ::= sigalg owner-name ...
rsa-public-key ::= rsa owner-name big-n big-ek
rsa-private-key ::= rsa owner-name big-n big-ek
!big-dk !big-p !big-q !big-kp
!big-kq !big-c2
dsa-public-key ::= dsa owner-name big-p big-q
big-alpha big-key
dsa-private-key ::= dsa owner-name big-p big-q
big-alpha big-key !big-secret
rsa-sig ::= big-val
dsa-sig ::= big-r big-s
elgamal-sig ::= big-r big-s
Each value labelled as `big-' is an unsigned multiple-
precision integer from keyring-ipint(2), represented as a
sequence of bytes with in big-endian order, as produced by
IPint->iptobytes with an extra leading zero byte added if
the top bit of the first byte is set, and then encoded in
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KEYTEXT(6) KEYTEXT(6)
base-64 (as by encoding(2)). Each value labelled `-name' is
utf (6) text not containing a newline; it is interpreted by
an application and need not be a name. The expiry time
exp-time is represented in decimal as seconds from the Epoch
(1 January 1970 00:00 GMT); if it is zero, no expiry time is
set. A label prefixed by `!' marks a value that should be
considered secret.
The hash of a key is computed over its textual encoding
according to the syntax above. A certificate's signature
value is produced by digitally signing using sigalg the hash
(using hashalg) of the concatenation of the value to be
authenticated, the signer-name in utf(6), a single space,
and the exp-time in decimal (with no leading zeroes). When
checking a signature, comparisons are done with values in
internal multiple-precision form (ie, as IPints), not in
base-64 form.
SEE ALSO
keyring-certtostr(2), keyring-getmsg(2), factotum(4),
keys(6), getauthinfo(8)
BUGS
The byte-array encoding of IPint should not require the
leading zero; it does so for compatibility with old keys.
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