/*----- Data formatting ---------------------------------------------------*/
+/* EC2OSP/OS2ECP bit mask. */
+#define EC_YBIT 1u /* The compressed @y@-coordinate */
+#define EC_XONLY 1u /* The @y@-coordinate is absent */
+#define EC_CMPR 2u /* Compressed @y@-coordinate */
+#define EC_LSB 2u /* Use `lsb' compression */
+#define EC_EXPLY 4u /* Explicit @y@-coordinate */
+#define EC_SORT 8u /* Use `sort' rather than `lsb' */
+
+/* --- @ec_ec2osp@ --- *
+ *
+ * Arguments: @ec_curve *c@ = elliptic curve
+ * @unsigned f@ = format flags for output
+ * @buf *b@ = pointer to a buffer
+ * @const ec *p@ = an elliptic curve point
+ *
+ * Returns: Zero on success, nonzero on failure.
+ *
+ * Use: Puts an elliptic curve point to the given buffer using the
+ * standard uncompressed format described in P1363 and SEC1.
+ * This requires at most @1 + 2 * c->f->noctets@ space in the
+ * buffer.
+ *
+ * Point compression features are determined by @f@ as follows.
+ * If @EC_CMPR@ is set then point compression is performed and a
+ * compressed form of the %$y$%-coordinate is contained in the
+ * first output byte; if @EC_SORT@ is set then P1363a `SORT'
+ * compression is used, otherwise LSB compression. If
+ * @EC_EXPLY@ is set, then an explicit %$y$%-coordinate is
+ * output in full. Otherwise the %$y$%-coordinate is
+ * suppressed.
+ *
+ * Returns failure (@-1@) if the flags are invalid, or if there
+ * isn't enough space in the output buffer.
+ */
+
+extern int ec_ec2osp(ec_curve */*c*/, unsigned /*f*/,
+ buf */*b*/, const ec */*p*/);
+
+/* --- @ec_os2ecp@ --- *
+ *
+ * Arguments: @ec_curve *c = elliptic curve
+ * @unsigned f@ = format flags for input
+ * @buf *b@ = pointer to a buffer
+ * @ec *d@ = an elliptic curve point
+ *
+ * Returns: Zero on success, nonzero on failure.
+ *
+ * Use: Reads an elliptic curve point from the given buffer using the
+ * standard uncompressed format described in P1363 and SEC1.
+ *
+ * Point compression features are determined by @f@ as follows.
+ * If @EC_LSB@ is set, then accept an LSB-compressed %$y$%-
+ * coordinate; if @EC_SORT@ is set, then accept a SORT-
+ * compressed %$y$%-coordinate; if @EC_EXPLY@ is set, then
+ * accept an explicit %$y$%-coordinate; if @EC_XONLY@ is set
+ * then accept a bare %$x$%-coordinate (a correct
+ * %$y$%-coordinate is chosen arbitrarily). Hybrid forms are
+ * acceptable, and the input is checked to verify that the
+ * redundant representations are consistent. If no flags are
+ * set in @f@, then no input (other than the point at infinity)
+ * will be acceptable.
+ */
+
+extern int ec_os2ecp(ec_curve */*c*/, unsigned /*f*/, buf */*b*/, ec */*d*/);
+
/* --- @ec_putraw@ --- *
*
* Arguments: @ec_curve *c@ = elliptic curve