Add support for X25519.

This brings in code from BoringSSL, which is mostly taken from SUPERCOP.

ok beck@ bcook@

1 files changed, 102 insertions, 0 deletions

diff --git a/src/lib/libcrypto/curve25519/curve25519_internal.h b/src/lib/libcrypto/curve25519/curve25519_internal.h
new file mode 100644
index 0000000000..09306b9ce8
--- /dev/null
+++ b/src/lib/libcrypto/curve25519/curve25519_internal.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef HEADER_CURVE25519_INTERNAL_H
+#define HEADER_CURVE25519_INTERNAL_H
+
+#include <stdint.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/* fe means field element. Here the field is \Z/(2^255-19). An element t,
+ * entries t[0]...t[9], represents the integer t[0]+2^26 t[1]+2^51 t[2]+2^77
+ * t[3]+2^102 t[4]+...+2^230 t[9]. Bounds on each t[i] vary depending on
+ * context.  */
+typedef int32_t fe[10];
+
+/* ge means group element.
+
+ * Here the group is the set of pairs (x,y) of field elements (see fe.h)
+ * satisfying -x^2 + y^2 = 1 + d x^2y^2
+ * where d = -121665/121666.
+ *
+ * Representations:
+ *   ge_p2 (projective): (X:Y:Z) satisfying x=X/Z, y=Y/Z
+ *   ge_p3 (extended): (X:Y:Z:T) satisfying x=X/Z, y=Y/Z, XY=ZT
+ *   ge_p1p1 (completed): ((X:Z),(Y:T)) satisfying x=X/Z, y=Y/T
+ *   ge_precomp (Duif): (y+x,y-x,2dxy) */
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+} ge_p2;
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+  fe T;
+} ge_p3;
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+  fe T;
+} ge_p1p1;
+
+typedef struct {
+  fe yplusx;
+  fe yminusx;
+  fe xy2d;
+} ge_precomp;
+
+typedef struct {
+  fe YplusX;
+  fe YminusX;
+  fe Z;
+  fe T2d;
+} ge_cached;
+
+void x25519_ge_tobytes(uint8_t *s, const ge_p2 *h);
+int x25519_ge_frombytes_vartime(ge_p3 *h, const uint8_t *s);
+void x25519_ge_p3_to_cached(ge_cached *r, const ge_p3 *p);
+void x25519_ge_p1p1_to_p2(ge_p2 *r, const ge_p1p1 *p);
+void x25519_ge_p1p1_to_p3(ge_p3 *r, const ge_p1p1 *p);
+void x25519_ge_add(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
+void x25519_ge_sub(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
+void x25519_ge_scalarmult_small_precomp(ge_p3 *h, const uint8_t a[32],
+    const uint8_t precomp_table[15 * 2 * 32]);
+void x25519_ge_scalarmult_base(ge_p3 *h, const uint8_t a[32]);
+void x25519_ge_scalarmult(ge_p2 *r, const uint8_t *scalar, const ge_p3 *A);
+void x25519_sc_reduce(uint8_t *s);
+
+void x25519_public_from_private(uint8_t out_public_value[32],
+    const uint8_t private_key[32]);
+
+void x25519_scalar_mult(uint8_t out[32], const uint8_t scalar[32],
+    const uint8_t point[32]);
+void x25519_scalar_mult_generic(uint8_t out[32], const uint8_t scalar[32],
+    const uint8_t point[32]);
+
+#if defined(__cplusplus)
+}  /* extern C */
+#endif
+
+#endif  /* HEADER_CURVE25519_INTERNAL_H */