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The current `group::Wnaf` implementation assumes `PrimeField::to_repr` returns a little endian encoding, so it doesn't work with our implementations of the NIST P-curves, which return a big endian SEC1 encoding. Following the general idea from RustCrypto/group#10, this adds an API which is guaranteed to return a little endian encoding which will always work with the current implementation of `group::Wnaf`. This is largely a stopgap solution which allows us to begin using `group::Wnaf` at all, though ideally we can find a more elegant upstream solution.
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@str4d curious what you had in mind here. I was wondering if |
tarcieri
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The wNAF implementation assumes a little endian representation for scalars, but `PrimeField::to_repr` returns an opaque representation which may be big endian and is in the case of our implementations of the NIST P-curves. RustCrypto/ff#10 added a stopgap API: `PrimeField::to_le_repr`, which is guaranteed to return a little endian representation. This commit switches `(rustcrypto-)group` to use it, which should make it compatible with our curves which otherwise use a big endian SEC1 representation.
tarcieri
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to RustCrypto/group
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Mar 31, 2026
The wNAF implementation assumes a little endian representation for scalars, but `PrimeField::to_repr` returns an opaque representation which may be big endian and is in the case of our implementations of the NIST P-curves. RustCrypto/ff#10 added a stopgap API: `PrimeField::to_le_repr`, which is guaranteed to return a little endian representation. This commit switches `(rustcrypto-)group` to use it, which should make it compatible with our curves which otherwise use a big endian SEC1 representation.
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The current
group::Wnafimplementation assumesPrimeField::to_reprreturns a little endian encoding, so it doesn't work with our implementations of the NIST P-curves, which return a big endian SEC1 encoding.Following the general idea from RustCrypto/group#10, this adds an API which is guaranteed to return a little endian encoding which will always work with the current implementation of
group::Wnaf.This is largely a stopgap solution which allows us to begin using
group::Wnafat all, though ideally we can find a more elegant upstream solution.cc @str4d @tob-scott-a