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authorMichael van der Westhuizen <michael@smart-africa.com>2014-07-02 10:17:26 +0200
committerTom Rini <trini@ti.com>2014-08-09 11:17:01 -0400
commite0f2f15534146729fdf2ce58b740121fd67eea1c (patch)
tree87cd55f630088b177050457ed0f3a3059997da17 /doc
parent53022c3113a6670d21f55262f511ae6a07bb3dc4 (diff)
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Implement generalised RSA public exponents for verified boot
Remove the verified boot limitation that only allows a single RSA public exponent of 65537 (F4). This change allows use with existing PKI infrastructure and has been tested with HSM-based PKI. Change the configuration OF tree format to store the RSA public exponent as a 64 bit integer and implement backward compatibility for verified boot configuration trees without this extra field. Parameterise vboot_test.sh to test different public exponents. Mathematics and other hard work by Andrew Bott. Tested with the following public exponents: 3, 5, 17, 257, 39981, 50457, 65537 and 4294967297. Signed-off-by: Andrew Bott <Andrew.Bott@ipaccess.com> Signed-off-by: Andrew Wishart <Andrew.Wishart@ipaccess.com> Signed-off-by: Neil Piercy <Neil.Piercy@ipaccess.com> Signed-off-by: Michael van der Westhuizen <michael@smart-africa.com> Cc: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/uImage.FIT/signature.txt4
1 files changed, 3 insertions, 1 deletions
diff --git a/doc/uImage.FIT/signature.txt b/doc/uImage.FIT/signature.txt
index a6ab543..b2f89fc 100644
--- a/doc/uImage.FIT/signature.txt
+++ b/doc/uImage.FIT/signature.txt
@@ -66,7 +66,8 @@ Creating an RSA key and certificate
-----------------------------------
To create a new public key, size 2048 bits:
-$ openssl genrsa -F4 -out keys/dev.key 2048
+$ openssl genpkey -algorithm RSA -out keys/dev.key \
+ -pkeyopt rsa_keygen_bits:2048 -pkeyopt rsa_keygen_pubexp:65537
To create a certificate for this:
@@ -159,6 +160,7 @@ For RSA the following are mandatory:
- rsa,num-bits: Number of key bits (e.g. 2048)
- rsa,modulus: Modulus (N) as a big-endian multi-word integer
+- rsa,exponent: Public exponent (E) as a 64 bit unsigned integer
- rsa,r-squared: (2^num-bits)^2 as a big-endian multi-word integer
- rsa,n0-inverse: -1 / modulus[0] mod 2^32