On Sun, 4 Oct 2015 03:50, phill(_at_)hallambaker(_dot_)com said:
Yes, hence the reason for my UDF design which salts the hash with the mime
content type of the data being hashed. Thus one fingerprint format can be
used for a S/MIME key or an OpenPGP key or an SSH key.
See rfc-4880, 12.2 (Key IDs and fingerprints)
Here are the fields of the hash material, with the example of a DSA
key:
a.1) 0x99 (1 octet)
a.2) high-order length octet of (b)-(e) (1 octet)
a.3) low-order length octet of (b)-(e) (1 octet)
b) version number = 4 (1 octet);
c) timestamp of key creation (4 octets);
d) algorithm (1 octet): 17 = DSA (example);
e) Algorithm-specific fields.
Algorithm-Specific Fields for DSA keys (example):
e.1) MPI of DSA prime p;
e.2) MPI of DSA group order q (q is a prime divisor of p-1);
e.3) MPI of DSA group generator g;
e.4) MPI of DSA public-key value y (= g**x mod p where x is secret).
also the MPI format is different from X.509 and from SSH.
Thus we already "salt" the fingerprints with version numbers and a
timestamp and get different fingerprints for these 3 protocols and most
likely for all protocols even for the same key material. For a v5 key
the fingerprint will also be different due to a.3b).
Salam-Shalom,
Werner
--
Die Gedanken sind frei. Ausnahmen regelt ein Bundesgesetz.
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