diff options
Diffstat (limited to 'pyecsca/codegen/templates/mult_precomp.c')
| -rw-r--r-- | pyecsca/codegen/templates/mult_precomp.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/pyecsca/codegen/templates/mult_precomp.c b/pyecsca/codegen/templates/mult_precomp.c new file mode 100644 index 0000000..cafa0a9 --- /dev/null +++ b/pyecsca/codegen/templates/mult_precomp.c @@ -0,0 +1,85 @@ +#include "mult.h" +#include "point.h" + +void scalar_mult_ltr(int order_blen, point_t **points, bn_t *scalar, point_t *point, curve_t *curve) { + {%- if scalarmult.complete %} + int nbits = order_blen - 1; + {%- else %} + int nbits = bn_bit_length(scalar) - 1; + {%- endif %} + + {%- if scalarmult.always %} + point_t *dummy = point_new(); + {%- endif %} + + for (int i = nbits; i >= 0; i--) { + if (bn_get_bit(scalar, i) == 1) { + point_accumulate(point, points[i], curve, point); + } else { + {%- if scalarmult.always %} + point_accumulate(point, points[i], curve, dummy); + {%- endif %} + } + } + + {%- if scalarmult.always %} + point_free(dummy); + {%- endif %} +} + +void scalar_mult_rtl(int order_blen, point_t **points, bn_t *scalar, point_t *point, curve_t *curve) { + {%- if scalarmult.complete %} + int nbits = order_blen; + {%- else %} + int nbits = bn_bit_length(scalar); + {%- endif %} + + {%- if scalarmult.always %} + point_t *dummy = point_new(); + {%- endif %} + + for (int i = 0; i < nbits; i++) { + if (bn_get_bit(scalar, i) == 1) { + point_accumulate(point, points[i], curve, point); + } else { + {%- if scalarmult.always %} + point_accumulate(point, points[i], curve, dummy); + {%- endif %} + } + } + + {%- if scalarmult.always %} + point_free(dummy); + {%- endif %} +} + +static void scalar_mult_inner(bn_t *scalar, point_t *point, curve_t *curve, point_t *out) { + point_t *q = point_copy(curve->neutral); + int order_blen = bn_bit_length(&curve->n); + point_t **points = malloc(sizeof(point_t *) * (order_blen + 1)); + + point_t *current = point_copy(point); + for (int i = 0; i < order_blen + 1; i++) { + points[i] = point_copy(current); + if (i != order_blen) { + point_dbl(current, curve, current); + } + } + point_free(current); + + {%- if scalarmult.direction == ProcessingDirection.LTR %} + scalar_mult_ltr(order_blen, points, scalar, q, curve); + {%- else %} + scalar_mult_rtl(order_blen, points, scalar, q, curve); + {%- endif %} + + {%- if "scl" in scalarmult.formulas %} + point_scl(q, curve, q); + {%- endif %} + point_set(q, out); + for (int i = 0; i < order_blen + 1; i++) { + point_free(points[i]); + } + free(points); + point_free(q); +}
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