The first step of RSA with the CRT optimization is to reduce our input
modulo p and q. We can do this in constant-time[*] with Montgomery
reduction. When p and q are the same size, Montgomery reduction's bounds
hold. We need two rounds of it because the first round gives us an
unwanted R^-1.
This does not appear to have a measurable impact on performance. Also
add a long TODO describing how to make the rest of the function
constant-time[*] which hopefully we'll get to later. RSA blinding should
protect us from it all, but make this constant-time anyway.
Since this and the follow-up work will special-case weird keys, add a
test that we don't break those unintentionally. (Though I am not above
breaking them intentionally someday...)
Thanks to Andres Erbsen for discussions on how to do this bit properly.
[*] Ignoring the pervasive bn_correct_top problem for the moment.
Change-Id: Ide099a9db8249cb6549be99c5f8791a39692ea81
Reviewed-on: https://boringssl-review.googlesource.com/24204
Reviewed-by: Adam Langley <agl@google.com>
This rewrites the internals with a "words" variant that can avoid
bn_correct_top. It still ultimately calls bn_correct_top as the calling
convention is sadly still BIGNUM, but we can lift that calling
convention out incrementally.
Performance seems to be comparable, if not faster.
Before:
Did 85000 ECDSA P-256 signing operations in 5030401us (16897.3 ops/sec)
Did 34278 ECDSA P-256 verify operations in 5048029us (6790.4 ops/sec)
After:
Did 85000 ECDSA P-256 signing operations in 5021057us (16928.7 ops/sec)
Did 34086 ECDSA P-256 verify operations in 5010416us (6803.0 ops/sec)
Change-Id: I1159746dfcc00726dc3f28396076a354556e6e7d
Reviewed-on: https://boringssl-review.googlesource.com/23065
Reviewed-by: Adam Langley <agl@google.com>
Generating a 2048-bit RSA key with e = 3 (don't do this), the failure
rate at 5*bits iterations appears to be around 7 failures in 1000 tries.
Bump the limit up to 32*bits. This should give a failure rate of around
2 failures in 10^14 tries.
(The FIPS 186-4 algorithm is meant for saner values of e, like 65537. e
= 3 implies a restrictive GCD requirement: the primes must both be 2 mod
3.)
Change-Id: Icd373f61e2eb90df5afaff9a0fc2b2fbb6ec3f0a
Reviewed-on: https://boringssl-review.googlesource.com/22584
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
crypto/{asn1,x509,x509v3,pem} were skipped as they are still OpenSSL
style.
Change-Id: I3cd9a60e1cb483a981aca325041f3fbce294247c
Reviewed-on: https://boringssl-review.googlesource.com/19504
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
We've got three versions of DATA_TOO_LARGE and two versions of
DATA_TOO_SMALL with no apparent distinction between them.
Change-Id: I18ca2cb71ffc31b04c8fd0be316c362da4d7daf9
Reviewed-on: https://boringssl-review.googlesource.com/17529
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Public and private RSA keys have the same type in OpenSSL, so it's
probably prudent for us to catch this case with an error rather than
crash. (As we do if you, say, configure RSA-PSS parameters on an Ed25519
EVP_PKEY.) Bindings libraries, in particular, tend to hit this sort of
then when their callers do silly things.
Change-Id: I2555e9bfe716a9f15273abd887a8459c682432dd
Reviewed-on: https://boringssl-review.googlesource.com/17325
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
This change allows blinding to be disabled without also having to remove
|e|, which would disable the CRT and the glitch checks. This is to
support disabling blinding in the FIPS power-on tests.
(Note: the case where |e| isn't set is tested by RSATest.OnlyDGiven.)
Change-Id: I28f18beda33b1687bf145f4cbdfd37ce262dd70f
Reviewed-on: https://boringssl-review.googlesource.com/17146
Commit-Queue: Adam Langley <alangley@gmail.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
This has since been done.
Change-Id: I498f845fa4ba3d1c04a5892831be4b07f31536d4
Reviewed-on: https://boringssl-review.googlesource.com/16124
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
