initial version of SQIsign

Co-authored-by: Jorge Chavez-Saab <jorgechavezsaab@gmail.com>
Co-authored-by: Maria Corte-Real Santos <36373796+mariascrs@users.noreply.github.com>
Co-authored-by: Luca De Feo <github@defeo.lu>
Co-authored-by: Jonathan Komada Eriksen <jonathan.eriksen97@gmail.com>
Co-authored-by: Basil Hess <bhe@zurich.ibm.com>
Co-authored-by: Antonin Leroux <18654258+tonioecto@users.noreply.github.com>
Co-authored-by: Patrick Longa <plonga@microsoft.com>
Co-authored-by: Lorenz Panny <lorenz@yx7.cc>
Co-authored-by: Francisco Rodríguez-Henríquez <francisco.rodriguez@tii.ae>
Co-authored-by: Sina Schaeffler <108983332+syndrakon@users.noreply.github.com>
Co-authored-by: Benjamin Wesolowski <19474926+Calodeon@users.noreply.github.com>

include/rng.h

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#ifndef rng_h
+#define rng_h
+
+/**
+ * Randombytes initialization.
+ * Initialization may be needed for some random number generators (e.g. CTR-DRBG).
+ *
+ * @param[in] entropy_input 48 bytes entropy input
+ * @param[in] personalization_string Personalization string
+ * @param[in] security_strength Security string
+ */
+void randombytes_init(unsigned char *entropy_input,
+                      unsigned char *personalization_string,
+                      int security_strength);
+
+/**
+ * Random byte generation.
+ * The caller is responsible to allocate sufficient memory to hold x.
+ *
+ * @param[out] x Memory to hold the random bytes.
+ * @param[in] xlen Number of random bytes to be generated
+ * @return int 0 on success, -1 otherwise
+ */
+int randombytes(unsigned char *x, unsigned long long xlen);
+
+#endif /* rng_h */