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ecp_curves: Minor refactoring of mbedtls_ecp_mod_p255_raw()

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* 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>
This commit is contained in:
Minos Galanakis 2023-05-17 15:01:08 +01:00
parent aada68f1be
commit 2daa374ea8
2 changed files with 32 additions and 52 deletions
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24
library/ecp_curves.c
View File

@ -5420,7 +5420,7 @@ int mbedtls_ecp_mod_p521_raw(mbedtls_mpi_uint *X, size_t X_limbs)
static int ecp_mod_p255(mbedtls_mpi *N) static int ecp_mod_p255(mbedtls_mpi *N)
{ {
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 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)); MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
ret = mbedtls_ecp_mod_p255_raw(N->p, expected_width); ret = mbedtls_ecp_mod_p255_raw(N->p, expected_width);
cleanup: cleanup:
@ -5433,32 +5433,26 @@ int mbedtls_ecp_mod_p255_raw(mbedtls_mpi_uint *X, size_t X_Limbs)
mbedtls_mpi_uint carry[P255_WIDTH]; mbedtls_mpi_uint carry[P255_WIDTH];
memset(carry, 0, sizeof(mbedtls_mpi_uint) * 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 */ /* Step 1: Reduction to P255_WIDTH limbs */
if (X_Limbs > P255_WIDTH) { if (X_Limbs > P255_WIDTH) {
/* Helper references for top part of N */ /* Helper references for top part of X */
mbedtls_mpi_uint * const NT_p = X + P255_WIDTH; mbedtls_mpi_uint * const A1 = X + P255_WIDTH;
const size_t NT_n = X_Limbs - P255_WIDTH; const size_t A1_limbs = X_Limbs - P255_WIDTH;
/* N = A0 + 38 * A1, capture carry out */ /* X = A0 + 38 * A1, capture carry out */
carry[0] = mbedtls_mpi_core_mla(X, P255_WIDTH, NT_p, NT_n, 38); carry[0] = mbedtls_mpi_core_mla(X, P255_WIDTH, A1, A1_limbs, 38);
/* Clear top part */ /* 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 /* Step 2: Reduce to <p
* Split as A0 + 2^255*c, with c a scalar, and compute A0 + 19*c */ * Split as A0 + 2^255*c, with c a scalar, and compute A0 + 19*c */
carry[0] <<= 1; carry[0] <<= 1;
carry[0] += (X[P255_WIDTH-1] >> (biL - 1)); carry[0] += (X[P255_WIDTH - 1] >> (biL - 1));
carry[0] *= 19; carry[0] *= 19;
/* Clear top bit */ /* 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); (void) mbedtls_mpi_core_add(X, X, &carry[0], P255_WIDTH);
return 0; return 0;

60
scripts/mbedtls_dev/ecp.py
View File

@ -728,53 +728,39 @@ class EcpP255Raw(bignum_common.ModOperationCommon,
"0", "1", "0", "1",
# Modulus - 1 # Modulus - 1
("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff" ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffec"),
"ffffffec"),
# Modulus + 1 # Modulus + 1
("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff" ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffee"),
"ffffffee"),
# 2^255 - 1 # 2^255 - 1
("7fffffffffffffffffffffffffffffffffffffffffffffffffffffff" ("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
"ffffffff"),
# Maximum canonical P255 multiplication result # Maximum canonical P255 multiplication result
("3fffffffffffffffffffffffffffffffffffffffffffffffffffffff" ("3fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffec"
"ffffffec000000000000000000000000000000000000000000000000" "0000000000000000000000000000000000000000000000000000000000000190"),
"0000000000000190"),
# First 8 number generated by random.getrandbits(510) - seed(2,2) # First 8 number generated by random.getrandbits(510) - seed(2,2)
("1019f0d64ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5" ("1019f0d64ee207f8da94e3e8ab73738fcf1822ffbc6887782b491044d5e34124"
"e341245c6e433715ba2bdd177219d30e7a269fd95bafc8f2a4d27bdcf4" "5c6e433715ba2bdd177219d30e7a269fd95bafc8f2a4d27bdcf4bb99f4bea973"),
"bb99f4bea973"), ("20948fa1feac7eb7dc38f519b91751dacdbd47d364be8049a372db8f6e405d93"
("20948fa1feac7eb7dc38f519b91751dacdbd47d364be8049a372db8f6e" "ffed9235288bc781ae66267594c9c9500925e4749b575bd13653f8dd9b1f282e"),
"405d93ffed9235288bc781ae66267594c9c9500925e4749b575bd13653" ("3a1893ea5186ee32ee8d7ee9770348a05d300cb90706a045defc044a09325626"
"f8dd9b1f282e"), "e6b58de744ab6cce80877b6f71e1f6d2ef8acd128b4f2fc15f3f57ebf30b94fa"),
("3a1893ea5186ee32ee8d7ee9770348a05d300cb90706a045defc044a09" ("20a6923522fe99a22c70501e533c91352d3d854e061b90303b08c6e33c729578"
"325626e6b58de744ab6cce80877b6f71e1f6d2ef8acd128b4f2fc15f3f" "2d6c797f8f7d9b782a1be9cd8697bbd0e2520e33e44c50556c71c4a66148a86f"),
"57ebf30b94fa"), ("3a248138e8168561867e5e15bc01bfce6a27e0dfcbf8754472154e76e4c11ab2"
("20a6923522fe99a22c70501e533c91352d3d854e061b90303b08c6e33c" "fec3f6b32e8d4b8a8f54f8ceacaab39e83844b40ffa9b9f15c14bc4a829e07b0"),
"7295782d6c797f8f7d9b782a1be9cd8697bbd0e2520e33e44c50556c71" ("2f450feab714210c665d7435c1066932f4767f26294365b2721dea3bf63f23d0"
"c4a66148a86f"), "dbe53fcafb2147df5ca495fa5a91c89b97eeab64ca2ce6bc5d3fd983c34c769f"),
("3a248138e8168561867e5e15bc01bfce6a27e0dfcbf8754472154e76e4" ("1d199effe202849da9643a295a9ac6decbd4d3e2d4dec9ef83f0be4e80371eb9"
"c11ab2fec3f6b32e8d4b8a8f54f8ceacaab39e83844b40ffa9b9f15c14" "7f81375eecc1cb6347733e847d718d733ff98ff387c56473a7a83ee0761ebfd2"),
"bc4a829e07b0"), ("3423c6ec531d6460f0caeef038c89b38a8acb5137c9260dc74e088a9b9492f25"
("2f450feab714210c665d7435c1066932f4767f26294365b2721dea3bf6" "8ebdbfe3eb9ac688b9d39cca91551e8259cc60b17604e4b4e73695c3e652c71a"),
"3f23d0dbe53fcafb2147df5ca495fa5a91c89b97eeab64ca2ce6bc5d3f"
"d983c34c769f"),
("1d199effe202849da9643a295a9ac6decbd4d3e2d4dec9ef83f0be4e80"
"371eb97f81375eecc1cb6347733e847d718d733ff98ff387c56473a7a8"
"3ee0761ebfd2"),
("3423c6ec531d6460f0caeef038c89b38a8acb5137c9260dc74e088a9b9"
"492f258ebdbfe3eb9ac688b9d39cca91551e8259cc60b17604e4b4e736"
"95c3e652c71a"),
# Next 2 number generated by random.getrandbits(255) # Next 2 number generated by random.getrandbits(255)
("62f1243644a4a8f69dc8db48e86ec9c6e06f291b2a838af8d5c44a4eb3" ("62f1243644a4a8f69dc8db48e86ec9c6e06f291b2a838af8d5c44a4eb3172062"),
"172062"), ("6a606e54b4c9e755cc9c3adcf515a8234da4daeb4f3f87777ad1f45ae9500ec9"),
("6a606e54b4c9e755cc9c3adcf515a8234da4daeb4f3f87777ad1f45ae9"
"500ec9"),
] ]
@property @property