1 files changed, 73 insertions, 0 deletions
diff --git a/lib/liboqs/src/common/rand/rand.h b/lib/liboqs/src/common/rand/rand.h
new file mode 100644
index 000000000..3499c2593
--- /dev/null
+++ b/lib/liboqs/src/common/rand/rand.h
@@ -0,0 +1,73 @@
+/**
+ * \file rand.h
+ * \brief Random number generator.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef OQS_RANDOM_H
+#define OQS_RANDOM_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include <oqs/common.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/** Algorithm identifier for system PRNG. */
+#define OQS_RAND_alg_system "system"
+/** Algorithm identifier for NIST deterministic RNG for KATs. */
+#define OQS_RAND_alg_nist_kat "NIST-KAT"
+/** Algorithm identifier for using OpenSSL's PRNG. */
+#define OQS_RAND_alg_openssl "OpenSSL"
+
+/**
+ * Switches OQS_randombytes to use the specified algorithm.
+ *
+ * @param[in] algorithm The name of the algorithm to use.
+ * @return OQS_SUCCESS if `algorithm` is a supported algorithm name, OQS_ERROR otherwise.
+ */
+OQS_API OQS_STATUS OQS_randombytes_switch_algorithm(const char *algorithm);
+
+/**
+ * Switches OQS_randombytes to use the given function.
+ *
+ * This allows additional custom RNGs besides the provided ones.  The provided RNG
+ * function must have the same signature as `OQS_randombytes`.
+ *
+ * @param[in] algorithm_ptr Pointer to the RNG function to use.
+ */
+OQS_API void OQS_randombytes_custom_algorithm(void (*algorithm_ptr)(uint8_t *, size_t));
+
+/**
+ * Fills the given memory with the requested number of (pseudo)random bytes.
+ *
+ * This implementation uses whichever algorithm has been selected by
+ * OQS_randombytes_switch_algorithm. The default is OQS_randombytes_system, which
+ * reads bytes directly from `/dev/urandom`.
+ *
+ * The caller is responsible for providing a buffer allocated with sufficient room.
+ *
+ * @param[out] random_array Pointer to the memory to fill with (pseudo)random bytes
+ * @param[in] bytes_to_read The number of random bytes to read into memory
+ */
+OQS_API void OQS_randombytes(uint8_t *random_array, size_t bytes_to_read);
+
+/**
+ * Initializes the NIST DRBG with a given seed and with 256-bit security.
+ *
+ * @param[in] entropy_input The seed; must be exactly 48 bytes
+ * @param[in] personalization_string An optional personalization string;
+ * may be NULL; if not NULL, must be at least 48 bytes long
+ */
+OQS_API void OQS_randombytes_nist_kat_init_256bit(const uint8_t *entropy_input, const uint8_t *personalization_string);
+
+#if defined(__cplusplus)
+} // extern "C"
+#endif
+
+#endif // OQS_RANDOM_H