Mike Frysinger wrote:
On Mon, Jul 20, 2009 at 09:51, Fred Keet wrote:
I'm in the process of writing an application that signs binary data for
loading
onto a Analog Devices BlackFin microprocessor. These chips have "built in"
support for verification of code. The chip gets loaded with the EC public
key,
and then you just update the code and signature on every update.
My problem is with their specific implementation of FIPS 186-2. They specify
the
parameters as below, and I would like to know which are important, and where
do I add them? They use a Koblitz curve for the keys (sect163k1). I'm under
the
impression that just using the correct curve should be sufficient, but would
like
to make sure.
1. m: 163 (dimension of binary field)
2. a: 1
3. b: 1 (a and b are the constants in the elliptic curve equation: y2 + xy =
x3 + ax + b)
4. Xg: 2FE13C0537BBC11ACAA07D793DE4E6D5E5C94EEE8
5. Yg: 289070FB05D38FF58321F2E800536D538CCDAA3D9 (Xg and Yg define a point G
on the curve above)
6. n: 4000000000000000000020108A2E0CC0D99F8A5EF (n is the order of the point
G)
7. k3: 7
8. k2: 6
9. k1: 3 (k1, k2, and k3 specify the field pentanomial x^m + x^k3 + x^k2 +
x^k1 + 1)
http://marc.info/?t=124725063100003&r=1&w=2
-mike
Thanks Mike.
At this point I've got code that generates the ec keys from the
sect163k1 curve, and then signs a block of data. When I compare this
with the ecsign utility they provide (apparently built on Miracl) the
two signatures do not match, so it seems that the curve parameters will
be necessary. I don't think the random number file should be necessary
if you've got /dev/random for OpenSSL to read data off of?
Having a look at ec_group_st we've got poly[], a, b which should
correlate with k1,k2,k3 and thus a, b, Xg, Yg and n should probably go
in field, similar to the values of _EC_NIST_CHAR2_163K. n, x, y, a, b
Already matches and I've no idea what p should be, so I'll just leave
that as is.
The code states to use the method functions to manipulate
ec_group_st.poly, but I've yet to find the relevant functions. Could
someone please point me to the correct file?
Analog Devices technical support just keeps telling me that they base
their stuff on FIPS 186-2 and to go look at http://www.cryptopp.com/ ,
http://ez.analog.com/thread/1157;jsessionid=29EF34998932BBB9621A1A09248ECC81
,
http://files.codes-sources.com/fichier_fullscreen.aspx?id=41412&f=Source+code%5CC+library%5Cmiracl%5Csource%5Cecsgen.cpp&lang=en
,
http://www.shamus.ie/ and
http://www.ellipticsemi.com/middleware_asymmetric.php which doesn't help
much with a OpenSSL implementation.
Fred
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