Implement polyvecl_uniform_gamma1 using 4-way Keccak
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This commit adds poly_uniform_gamma1_4x which implements uniform sampling in [-(MLDSA_GAMMA1 - 1), MLDSA_GAMMA1] using 4-way batched Keccak. It then implements polyvecl_uniform_gamma1 using the new batched function. L = 4 is implemented using one call to poly_uniform_gamma1_4x. L = 5 is implemented using one call to poly_uniform_gamma1_4x and one call to poly_uniform_gamma1 L = 7 is implemented using two call to poly_uniform_gamma1_4x (with one polynomial being wasted). Signed-off-by: Matthias J. Kannwischer <[email protected]>
The poly_uniform_gamma1 function is the last one using the stream256 instead of the standard keccak APIs. This commit refactors it to be in-line with the batched implementation as well as the xof128 function. The initialization function is removed and inlined into poly_uniform_gamma1. The CBMC proof is adjusted accordingly. Signed-off-by: Matthias J. Kannwischer <[email protected]>
Some Keccak implementations (e.g., liboqs) may dynamically allocate the Keccak
state in the _init() function. We, hence, need an explicit _release() function
to potentially free this memory.
In mldsa-native this is a no-op (or it zeros out the state once we have
secure stack zeroziation).
This commit adds the _release functions for both shake128 and shake256.
According mld_xof{128,256}_release macros are added to symmetric.h.
Function calls to the _release functions are added in all places that use the
mld_xof APIs.
CBMC proofs are amended for those functions to in-line the empty release
functions.
Signed-off-by: Matthias J. Kannwischer <[email protected]>
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s1,s2vectors using 4-way batched Keccak #245poly_uniform_gamma1_4x#212This commit adds poly_uniform_gamma1_4x which implements uniform
sampling in [-(MLDSA_GAMMA1 - 1), MLDSA_GAMMA1] using 4-way batched
Keccak. It then implements polyvecl_uniform_gamma1 using
the new batched function.
L = 4 is implemented using one call to poly_uniform_gamma1_4x.
L = 5 is implemented using one call to poly_uniform_gamma1_4x and one call to
poly_uniform_gamma1
L = 7 is implemented using two call to poly_uniform_gamma1_4x (with one
polynomial being wasted).