This is slower, but constant-time. It intentionally omits the signed
digit optimization because we cannot be sure the doubling case will be
unreachable for all curves. This is a fallback generic implementation
for curves which we must support for compatibility but which are not
common or important enough to justify curve-specific work.
Before:
Did 814 ECDH P-384 operations in 1085384us (750.0 ops/sec)
Did 1430 ECDSA P-384 signing operations in 1081988us (1321.6 ops/sec)
Did 308 ECDH P-521 operations in 1057741us (291.2 ops/sec)
Did 539 ECDSA P-521 signing operations in 1049797us (513.4 ops/sec)
After:
Did 715 ECDH P-384 operations in 1080161us (661.9 ops/sec)
Did 1188 ECDSA P-384 verify operations in 1069567us (1110.7 ops/sec)
Did 275 ECDH P-521 operations in 1060503us (259.3 ops/sec)
Did 506 ECDSA P-521 signing operations in 1084739us (466.5 ops/sec)
But we're still faster than the old BIGNUM implementation. EC_FELEM
more than paid for both the loss of points_make_affine and this CL.
Bug: 239
Change-Id: I65d71a731aad16b523928ee47618822d503ea704
Reviewed-on: https://boringssl-review.googlesource.com/27708
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
EC_POINT is split into the existing public EC_POINT (where the caller is
sanity-checked about group mismatches) and the low-level EC_RAW_POINT
(which, like EC_FELEM and EC_SCALAR, assume that is your problem and is
a plain old struct). Having both EC_POINT and EC_RAW_POINT is a little
silly, but we're going to want different type signatures for functions
which return void anyway (my plan is to lift a non-BIGNUM
get_affine_coordinates up through the ECDSA and ECDH code), so I think
it's fine.
This wasn't strictly necessary, but wnaf.c is a lot tidier now. Perf is
a wash; once we get up to this layer, it's only 8 entries in the table
so not particularly interesting.
Bug: 239
Change-Id: I8ace749393d359f42649a5bb0734597bb7c07a2e
Reviewed-on: https://boringssl-review.googlesource.com/27706
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
This introduces EC_FELEM, which is analogous to EC_SCALAR. It is used
for EC_POINT's representation in the generic EC_METHOD, as well as
random operations on tuned EC_METHODs that still are implemented
genericly.
Unlike EC_SCALAR, EC_FELEM's exact representation is awkwardly specific
to the EC_METHOD, analogous to how the old values were BIGNUMs but may
or may not have been in Montgomery form. This is kind of a nuisance, but
no more than before. (If p224-64.c were easily convertable to Montgomery
form, we could say |EC_FELEM| is always in Montgomery form. If we
exposed the internal add and double implementations in each of the
curves, we could give |EC_POINT| an |EC_METHOD|-specific representation
and |EC_FELEM| is purely a |EC_GFp_mont_method| type. I'll leave this
for later.)
The generic add and doubling formulas are aligned with the formulas
proved in fiat-crypto. Those only applied to a = -3, so I've proved a
generic one in https://github.com/mit-plv/fiat-crypto/pull/356, in case
someone uses a custom curve. The new formulas are verified,
constant-time, and swap a multiply for a square. As expressed in
fiat-crypto they do use more temporaries, but this seems to be fine with
stack-allocated EC_FELEMs. (We can try to help the compiler later,
but benchamrks below suggest this isn't necessary.)
Unlike BIGNUM, EC_FELEM can be stack-allocated. It also captures the
bounds in the type system and, in particular, that the width is correct,
which will make it easier to select a point in constant-time in the
future. (Indeed the old code did not always have the correct width. Its
point formula involved halving and implemented this in variable time and
variable width.)
Before:
Did 77274 ECDH P-256 operations in 10046087us (7692.0 ops/sec)
Did 5959 ECDH P-384 operations in 10031701us (594.0 ops/sec)
Did 10815 ECDSA P-384 signing operations in 10087892us (1072.1 ops/sec)
Did 8976 ECDSA P-384 verify operations in 10071038us (891.3 ops/sec)
Did 2600 ECDH P-521 operations in 10091688us (257.6 ops/sec)
Did 4590 ECDSA P-521 signing operations in 10055195us (456.5 ops/sec)
Did 3811 ECDSA P-521 verify operations in 10003574us (381.0 ops/sec)
After:
Did 77736 ECDH P-256 operations in 10029858us (7750.5 ops/sec) [+0.8%]
Did 7519 ECDH P-384 operations in 10068076us (746.8 ops/sec) [+25.7%]
Did 13335 ECDSA P-384 signing operations in 10029962us (1329.5 ops/sec) [+24.0%]
Did 11021 ECDSA P-384 verify operations in 10088600us (1092.4 ops/sec) [+22.6%]
Did 2912 ECDH P-521 operations in 10001325us (291.2 ops/sec) [+13.0%]
Did 5150 ECDSA P-521 signing operations in 10027462us (513.6 ops/sec) [+12.5%]
Did 4264 ECDSA P-521 verify operations in 10069694us (423.4 ops/sec) [+11.1%]
This more than pays for removing points_make_affine previously and even
speeds up ECDH P-256 slightly. (The point-on-curve check uses the
generic code.)
Next is to push the stack-allocating up to ec_wNAF_mul, followed by a
constant-time single-point multiplication.
Bug: 239
Change-Id: I44a2dff7c52522e491d0f8cffff64c4ab5cd353c
Reviewed-on: https://boringssl-review.googlesource.com/27668
Reviewed-by: Adam Langley <agl@google.com>
As the point may be the output of some private key operation, whether Z
accidentally hit one is secret.
Bug: 239
Change-Id: I7db34cd3b5dd5ca4b96980e8993a9b4eda49eb88
Reviewed-on: https://boringssl-review.googlesource.com/27664
Reviewed-by: Adam Langley <alangley@gmail.com>
This introduces a hook for the OpenSSL assembly.
Change-Id: I35e0588f0ed5bed375b12f738d16c9f46ceedeea
Reviewed-on: https://boringssl-review.googlesource.com/27592
Reviewed-by: Adam Langley <alangley@gmail.com>
These empty states aren't any use to either caller or implementor.
Change-Id: If0b748afeeb79e4a1386182e61c5b5ecf838de62
Reviewed-on: https://boringssl-review.googlesource.com/25254
Reviewed-by: Adam Langley <agl@google.com>
The fiat-crypto-generated code uses the Montgomery form implementation
strategy, for both 32-bit and 64-bit code.
64-bit throughput seems slower, but the difference is smaller than noise between repetitions (-2%?)
32-bit throughput has decreased significantly for ECDH (-40%). I am
attributing this to the change from varibale-time scalar multiplication
to constant-time scalar multiplication. Due to the same bottleneck,
ECDSA verification still uses the old code (otherwise there would have
been a 60% throughput decrease). On the other hand, ECDSA signing
throughput has increased slightly (+10%), perhaps due to the use of a
precomputed table of multiples of the base point.
64-bit benchmarks (Google Cloud Haswell):
with this change:
Did 9126 ECDH P-256 operations in 1009572us (9039.5 ops/sec)
Did 23000 ECDSA P-256 signing operations in 1039832us (22119.0 ops/sec)
Did 8820 ECDSA P-256 verify operations in 1024242us (8611.2 ops/sec)
master (40e8c921ca):
Did 9340 ECDH P-256 operations in 1017975us (9175.1 ops/sec)
Did 23000 ECDSA P-256 signing operations in 1039820us (22119.2 ops/sec)
Did 8688 ECDSA P-256 verify operations in 1021108us (8508.4 ops/sec)
benchmarks on ARMv7 (LG Nexus 4):
with this change:
Did 150 ECDH P-256 operations in 1029726us (145.7 ops/sec)
Did 506 ECDSA P-256 signing operations in 1065192us (475.0 ops/sec)
Did 363 ECDSA P-256 verify operations in 1033298us (351.3 ops/sec)
master (2fce1beda0):
Did 245 ECDH P-256 operations in 1017518us (240.8 ops/sec)
Did 473 ECDSA P-256 signing operations in 1086281us (435.4 ops/sec)
Did 360 ECDSA P-256 verify operations in 1003846us (358.6 ops/sec)
64-bit tables converted as follows:
import re, sys, math
p = 2**256 - 2**224 + 2**192 + 2**96 - 1
R = 2**256
def convert(t):
x0, s1, x1, s2, x2, s3, x3 = t.groups()
v = int(x0, 0) + 2**64 * (int(x1, 0) + 2**64*(int(x2,0) + 2**64*(int(x3, 0)) ))
w = v*R%p
y0 = hex(w%(2**64))
y1 = hex((w>>64)%(2**64))
y2 = hex((w>>(2*64))%(2**64))
y3 = hex((w>>(3*64))%(2**64))
ww = int(y0, 0) + 2**64 * (int(y1, 0) + 2**64*(int(y2,0) + 2**64*(int(y3, 0)) ))
if ww != v*R%p:
print(x0,x1,x2,x3)
print(hex(v))
print(y0,y1,y2,y3)
print(hex(w))
print(hex(ww))
assert 0
return '{'+y0+s1+y1+s2+y2+s3+y3+'}'
fe_re = re.compile('{'+r'(\s*,\s*)'.join(r'(\d+|0x[abcdefABCDEF0123456789]+)' for i in range(4)) + '}')
print (re.sub(fe_re, convert, sys.stdin.read()).rstrip('\n'))
32-bit tables converted from 64-bit tables
Change-Id: I52d6e5504fcb6ca2e8b0ee13727f4500c80c1799
Reviewed-on: https://boringssl-review.googlesource.com/23244
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>
I really need to resurrect the CL to make them entirely static
(https://crbug.com/boringssl/20), but, in the meantime, to make
replacing the EC_METHOD pointer in EC_POINT with EC_GROUP not
*completely* insane, make them refcounted.
OpenSSL did not do this because their EC_GROUPs are mutable
(EC_GROUP_set_asn1_flag and EC_GROUP_set_point_conversion_form). Ours
are immutable but for the two-function dance around custom curves (more
of OpenSSL's habit of making their objects too complex), which is good
enough to refcount.
Change-Id: I3650993737a97da0ddcf0e5fb7a15876e724cadc
Reviewed-on: https://boringssl-review.googlesource.com/22244
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>
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>
The names in the P-224 code collided with the P-256 code and thus many
of the functions and constants in the P-224 code have been prefixed.
Change-Id: I6bcd304640c539d0483d129d5eaf1702894929a8
Reviewed-on: https://boringssl-review.googlesource.com/15847
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>
