second-round version of SQIsign

Co-authored-by: Marius A. Aardal <marius.andre.aardal@gmail.com>
Co-authored-by: Gora Adj <gora.adj@tii.ae>
Co-authored-by: Diego F. Aranha <dfaranha@cs.au.dk>
Co-authored-by: Andrea Basso <sqisign@andreabasso.com>
Co-authored-by: Isaac Andrés Canales Martínez <icanalesm0500@gmail.com>
Co-authored-by: Jorge Chávez-Saab <jorgechavezsaab@gmail.com>
Co-authored-by: Maria Corte-Real Santos <mariascrsantos98@gmail.com>
Co-authored-by: Luca De Feo <github@defeo.lu>
Co-authored-by: Max Duparc <max.duparc@epfl.ch>
Co-authored-by: Jonathan Komada Eriksen <jonathan.eriksen97@gmail.com>
Co-authored-by: Décio Luiz Gazzoni Filho <decio@decpp.net>
Co-authored-by: Basil Hess <bhe@zurich.ibm.com>
Co-authored-by: Antonin Leroux <antonin.leroux@polytechnique.org>
Co-authored-by: Patrick Longa <plonga@microsoft.com>
Co-authored-by: Luciano Maino <mainoluciano.96@gmail.com>
Co-authored-by: Michael Meyer <michael@random-oracles.org>
Co-authored-by: Hiroshi Onuki <onuki@mist.i.u-tokyo.ac.jp>
Co-authored-by: Lorenz Panny <lorenz@yx7.cc>
Co-authored-by: Giacomo Pope <giacomopope@gmail.com>
Co-authored-by: Krijn Reijnders <reijnderskrijn@gmail.com>
Co-authored-by: Damien Robert <damien.robert@inria.fr>
Co-authored-by: Francisco Rodríguez-Henriquez <francisco.rodriguez@tii.ae>
Co-authored-by: Sina Schaeffler <sschaeffle@student.ethz.ch>
Co-authored-by: Benjamin Wesolowski <benjamin.wesolowski@ens-lyon.fr>

scripts/precomp/ec_params.sage

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+
+from sage.all import *
+from parameters import p, f
+
+if __name__ == '__main__':
+
+    cof = (p+1)//(2**f)
+
+    from cformat import Object, ObjectFormatter
+
+    obj_cof = ObjectFormatter(
+        [
+            Object('digit_t[]', 'p_cofactor_for_2f', [cof]),
+        ]
+    )
+
+    with open("include/ec_params.h", "w") as hfile:
+        with open("ec_params.c", "w") as cfile:
+
+            hfile.write('#ifndef EC_PARAMS_H\n')
+            hfile.write('#define EC_PARAMS_H\n')
+            hfile.write('\n')
+
+            hfile.write('#include <fp.h>\n')
+            cfile.write('#include <ec_params.h>\n')
+            hfile.write('\n')
+
+            hfile.write(f'#define TORSION_EVEN_POWER {f}\n')
+            hfile.write('\n')
+
+            hfile.write('// p+1 divided by the power of 2\n')
+            cfile.write('// p+1 divided by the power of 2\n')
+            obj_cof.header(file=hfile)
+            obj_cof.implementation(file=cfile)
+            hfile.write(f'#define P_COFACTOR_FOR_2F_BITLENGTH {((p+1)//(2**f)).bit_length()}\n')
+            hfile.write('\n')
+            cfile.write('\n')
+
+
+            hfile.write('#endif\n')