ecp_curves: Minor refactoring of `mbedtls_ecp_mod_p255_raw()`
* Fixed whitespace issues.
* Renamed variables to align with bignum conventions.
* Updated alignment on test input data.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 98e2f95..fe62fec 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -5420,7 +5420,7 @@
static int ecp_mod_p255(mbedtls_mpi *N)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- size_t expected_width = 2 * ((256 + biL - 1) / biL);
+ size_t expected_width = 2 * ((255 + biL - 1) / biL);
MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
ret = mbedtls_ecp_mod_p255_raw(N->p, expected_width);
cleanup:
@@ -5433,32 +5433,26 @@
mbedtls_mpi_uint carry[P255_WIDTH];
memset(carry, 0, sizeof(mbedtls_mpi_uint) * P255_WIDTH);
- if (X_Limbs > 2*P255_WIDTH) {
- X_Limbs = 2*P255_WIDTH;
- } else if (X_Limbs < P255_WIDTH) {
- return 0;
- }
-
/* Step 1: Reduction to P255_WIDTH limbs */
if (X_Limbs > P255_WIDTH) {
- /* Helper references for top part of N */
- mbedtls_mpi_uint * const NT_p = X + P255_WIDTH;
- const size_t NT_n = X_Limbs - P255_WIDTH;
+ /* Helper references for top part of X */
+ mbedtls_mpi_uint * const A1 = X + P255_WIDTH;
+ const size_t A1_limbs = X_Limbs - P255_WIDTH;
- /* N = A0 + 38 * A1, capture carry out */
- carry[0] = mbedtls_mpi_core_mla(X, P255_WIDTH, NT_p, NT_n, 38);
+ /* X = A0 + 38 * A1, capture carry out */
+ carry[0] = mbedtls_mpi_core_mla(X, P255_WIDTH, A1, A1_limbs, 38);
/* Clear top part */
- memset(NT_p, 0, sizeof(mbedtls_mpi_uint) * NT_n);
+ memset(A1, 0, sizeof(mbedtls_mpi_uint) * A1_limbs);
}
/* Step 2: Reduce to <p
* Split as A0 + 2^255*c, with c a scalar, and compute A0 + 19*c */
carry[0] <<= 1;
- carry[0] += (X[P255_WIDTH-1] >> (biL - 1));
+ carry[0] += (X[P255_WIDTH - 1] >> (biL - 1));
carry[0] *= 19;
/* Clear top bit */
- X[P255_WIDTH-1] <<= 1; X[P255_WIDTH-1] >>= 1;
+ X[P255_WIDTH - 1] <<= 1; X[P255_WIDTH - 1] >>= 1;
(void) mbedtls_mpi_core_add(X, X, &carry[0], P255_WIDTH);
return 0;
diff --git a/scripts/mbedtls_dev/ecp.py b/scripts/mbedtls_dev/ecp.py
index 7626eda..02db438 100644
--- a/scripts/mbedtls_dev/ecp.py
+++ b/scripts/mbedtls_dev/ecp.py
@@ -728,53 +728,39 @@
"0", "1",
# Modulus - 1
- ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff"
- "ffffffec"),
+ ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffec"),
# Modulus + 1
- ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff"
- "ffffffee"),
+ ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffee"),
# 2^255 - 1
- ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff"
- "ffffffff"),
+ ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
# Maximum canonical P255 multiplication result
- ("3fffffffffffffffffffffffffffffffffffffffffffffffffffffff"
- "ffffffec000000000000000000000000000000000000000000000000"
- "0000000000000190"),
+ ("3fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffec"
+ "0000000000000000000000000000000000000000000000000000000000000190"),
# First 8 number generated by random.getrandbits(510) - seed(2,2)
- ("1019f0d64ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5"
- "e341245c6e433715ba2bdd177219d30e7a269fd95bafc8f2a4d27bdcf4"
- "bb99f4bea973"),
- ("20948fa1feac7eb7dc38f519b91751dacdbd47d364be8049a372db8f6e"
- "405d93ffed9235288bc781ae66267594c9c9500925e4749b575bd13653"
- "f8dd9b1f282e"),
- ("3a1893ea5186ee32ee8d7ee9770348a05d300cb90706a045defc044a09"
- "325626e6b58de744ab6cce80877b6f71e1f6d2ef8acd128b4f2fc15f3f"
- "57ebf30b94fa"),
- ("20a6923522fe99a22c70501e533c91352d3d854e061b90303b08c6e33c"
- "7295782d6c797f8f7d9b782a1be9cd8697bbd0e2520e33e44c50556c71"
- "c4a66148a86f"),
- ("3a248138e8168561867e5e15bc01bfce6a27e0dfcbf8754472154e76e4"
- "c11ab2fec3f6b32e8d4b8a8f54f8ceacaab39e83844b40ffa9b9f15c14"
- "bc4a829e07b0"),
- ("2f450feab714210c665d7435c1066932f4767f26294365b2721dea3bf6"
- "3f23d0dbe53fcafb2147df5ca495fa5a91c89b97eeab64ca2ce6bc5d3f"
- "d983c34c769f"),
- ("1d199effe202849da9643a295a9ac6decbd4d3e2d4dec9ef83f0be4e80"
- "371eb97f81375eecc1cb6347733e847d718d733ff98ff387c56473a7a8"
- "3ee0761ebfd2"),
- ("3423c6ec531d6460f0caeef038c89b38a8acb5137c9260dc74e088a9b9"
- "492f258ebdbfe3eb9ac688b9d39cca91551e8259cc60b17604e4b4e736"
- "95c3e652c71a"),
+ ("1019f0d64ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5e34124"
+ "5c6e433715ba2bdd177219d30e7a269fd95bafc8f2a4d27bdcf4bb99f4bea973"),
+ ("20948fa1feac7eb7dc38f519b91751dacdbd47d364be8049a372db8f6e405d93"
+ "ffed9235288bc781ae66267594c9c9500925e4749b575bd13653f8dd9b1f282e"),
+ ("3a1893ea5186ee32ee8d7ee9770348a05d300cb90706a045defc044a09325626"
+ "e6b58de744ab6cce80877b6f71e1f6d2ef8acd128b4f2fc15f3f57ebf30b94fa"),
+ ("20a6923522fe99a22c70501e533c91352d3d854e061b90303b08c6e33c729578"
+ "2d6c797f8f7d9b782a1be9cd8697bbd0e2520e33e44c50556c71c4a66148a86f"),
+ ("3a248138e8168561867e5e15bc01bfce6a27e0dfcbf8754472154e76e4c11ab2"
+ "fec3f6b32e8d4b8a8f54f8ceacaab39e83844b40ffa9b9f15c14bc4a829e07b0"),
+ ("2f450feab714210c665d7435c1066932f4767f26294365b2721dea3bf63f23d0"
+ "dbe53fcafb2147df5ca495fa5a91c89b97eeab64ca2ce6bc5d3fd983c34c769f"),
+ ("1d199effe202849da9643a295a9ac6decbd4d3e2d4dec9ef83f0be4e80371eb9"
+ "7f81375eecc1cb6347733e847d718d733ff98ff387c56473a7a83ee0761ebfd2"),
+ ("3423c6ec531d6460f0caeef038c89b38a8acb5137c9260dc74e088a9b9492f25"
+ "8ebdbfe3eb9ac688b9d39cca91551e8259cc60b17604e4b4e73695c3e652c71a"),
# Next 2 number generated by random.getrandbits(255)
- ("62f1243644a4a8f69dc8db48e86ec9c6e06f291b2a838af8d5c44a4eb3"
- "172062"),
- ("6a606e54b4c9e755cc9c3adcf515a8234da4daeb4f3f87777ad1f45ae9"
- "500ec9"),
+ ("62f1243644a4a8f69dc8db48e86ec9c6e06f291b2a838af8d5c44a4eb3172062"),
+ ("6a606e54b4c9e755cc9c3adcf515a8234da4daeb4f3f87777ad1f45ae9500ec9"),
]
@property