unikernel/duniverse/kdf/scrypt/salsa-core.c

@@ -0,0 +1,65 @@
+#include <stdint.h>
+
+#define CAML_NAME_SPACE
+#include <caml/mlvalues.h>
+#include <caml/bigarray.h>
+
+static inline uint32_t r(uint32_t a, int b) {
+  int rs = 32 - b;
+  return (a << b) | (a >> rs);
+}
+
+static inline uint32_t combine(uint32_t y0, uint32_t y1, uint32_t y2, int shift) {
+  return r(y1 + y2, shift) ^ y0;
+}
+
+static inline void quarterround(uint32_t *x, int y0, int y1, int y2, int y3) {
+  x[y1] = combine(x[y1], x[y0], x[y3], 7);
+  x[y2] = combine(x[y2], x[y1], x[y0], 9);
+  x[y3] = combine(x[y3], x[y2], x[y1], 13);
+  x[y0] = combine(x[y0], x[y3], x[y2], 18);
+}
+
+static inline uint32_t get_u32_le(const uint8_t *input, int offset) {
+  return input[offset]
+    | (input[offset + 1] << 8)
+    | (input[offset + 2] << 16)
+    | (input[offset + 3] << 24);
+}
+
+static inline void set_u32_le(uint8_t *input, int offset, uint32_t value) {
+  input[offset] = (uint8_t) value;
+  input[offset + 1] = (uint8_t) (value >> 8);
+  input[offset + 2] = (uint8_t) (value >> 16);
+  input[offset + 3] = (uint8_t) (value >> 24);
+}
+
+static void salsa_core(int count, const uint8_t *src, uint8_t *dst) {
+  uint32_t x[16];
+  for (int i = 0; i < 16; i++) {
+    x[i] = get_u32_le(src, i * 4);
+  }
+  for (int i = 0; i < count; i++) {
+    quarterround(x, 0, 4, 8, 12);
+    quarterround(x, 5, 9, 13, 1);
+    quarterround(x, 10, 14, 2, 6);
+    quarterround(x, 15, 3, 7, 11);
+
+    quarterround(x, 0, 1, 2, 3);
+    quarterround(x, 5, 6, 7, 4);
+    quarterround(x, 10, 11, 8, 9);
+    quarterround(x, 15, 12, 13, 14);
+  }
+  for (int i = 0; i < 16; i++) {
+    uint32_t xi = x[i];
+    uint32_t hj = get_u32_le(src, i * 4);
+    set_u32_le(dst, i * 4, xi + hj);
+  }
+}
+
+CAMLprim value
+caml_salsa_core(value count, value src, value dst)
+{
+  salsa_core(Int_val(count), (const uint8_t*)(String_val(src)), Bytes_val(dst));
+  return Val_unit;
+}