ec_scalar: add non-const accessor and construct by value #1080
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
evoskuil
reviewed
Dec 8, 2018
| @@ -32,6 +32,7 @@ class BC_API ec_scalar | |||
| /// Constructors. | |||
| ec_scalar(); | |||
| ec_scalar(const ec_secret& secret); | |||
| ec_scalar(uint64_t value); | |||
There was a problem hiding this comment.
This constructor was removed from the original pull request. There is no mapping from a 64 bit value to an ec_secret nor should a 64 bit value ever be considered a secret. If the caller intends to implement such a mapping it should be implemented outside of this class and passed in as an ec_secret.
| @@ -128,5 +136,9 @@ const ec_secret& ec_scalar::secret() const | |||
| { | |||
| return secret_; | |||
| } | |||
| ec_secret& ec_scalar::secret() | |||
There was a problem hiding this comment.
This allows the caller to modify ec_scalar internals, which should only be done via the assignment operator (which btw is equally efficient).
| @@ -21,71 +21,19 @@ | |||
|
|
|||
| using namespace bc; | |||
|
|
|||
| BOOST_AUTO_TEST_SUITE(ec_scalar_tests) | |||
| BOOST_AUTO_TEST_SUITE(ec_point_tests) | |||
evoskuil
reviewed
Dec 9, 2018
| { | ||
| secret_ = zero; | ||
| auto serial = make_unsafe_serializer(secret_.end() - 4); | ||
| serial.write_4_bytes_big_endian(value); |
There was a problem hiding this comment.
Writing 4 bytes casted from an 8 byte value, as big endian, into the high order bytes of a 32 byte value appears completely arbitrary and unrelated to the behavior of an ec scalar.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
As the title says.
non-const accessor is needed to be able to modify underlying secret value without unecessary copying.
construct by value is very useful for doing calculations where we blind output amounts (for example).
Also the unit test filenames for ec_point and ec_scalar were reversed. I switched them over.