diff -r c7c34916027a -r 177826044cd9 wp/wp-includes/sodium_compat/src/Core/X25519.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/sodium_compat/src/Core/X25519.php	Mon Oct 14 18:28:13 2019 +0200
@@ -0,0 +1,327 @@
+<?php
+
+if (class_exists('ParagonIE_Sodium_Core_X25519', false)) {
+    return;
+}
+
+/**
+ * Class ParagonIE_Sodium_Core_X25519
+ */
+abstract class ParagonIE_Sodium_Core_X25519 extends ParagonIE_Sodium_Core_Curve25519
+{
+    /**
+     * Alters the objects passed to this method in place.
+     *
+     * @internal You should not use this directly from another application
+     *
+     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
+     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
+     * @param int $b
+     * @return void
+     * @psalm-suppress MixedAssignment
+     */
+    public static function fe_cswap(
+        ParagonIE_Sodium_Core_Curve25519_Fe $f,
+        ParagonIE_Sodium_Core_Curve25519_Fe $g,
+        $b = 0
+    ) {
+        $f0 = (int) $f[0];
+        $f1 = (int) $f[1];
+        $f2 = (int) $f[2];
+        $f3 = (int) $f[3];
+        $f4 = (int) $f[4];
+        $f5 = (int) $f[5];
+        $f6 = (int) $f[6];
+        $f7 = (int) $f[7];
+        $f8 = (int) $f[8];
+        $f9 = (int) $f[9];
+        $g0 = (int) $g[0];
+        $g1 = (int) $g[1];
+        $g2 = (int) $g[2];
+        $g3 = (int) $g[3];
+        $g4 = (int) $g[4];
+        $g5 = (int) $g[5];
+        $g6 = (int) $g[6];
+        $g7 = (int) $g[7];
+        $g8 = (int) $g[8];
+        $g9 = (int) $g[9];
+        $b = -$b;
+        $x0 = ($f0 ^ $g0) & $b;
+        $x1 = ($f1 ^ $g1) & $b;
+        $x2 = ($f2 ^ $g2) & $b;
+        $x3 = ($f3 ^ $g3) & $b;
+        $x4 = ($f4 ^ $g4) & $b;
+        $x5 = ($f5 ^ $g5) & $b;
+        $x6 = ($f6 ^ $g6) & $b;
+        $x7 = ($f7 ^ $g7) & $b;
+        $x8 = ($f8 ^ $g8) & $b;
+        $x9 = ($f9 ^ $g9) & $b;
+        $f[0] = $f0 ^ $x0;
+        $f[1] = $f1 ^ $x1;
+        $f[2] = $f2 ^ $x2;
+        $f[3] = $f3 ^ $x3;
+        $f[4] = $f4 ^ $x4;
+        $f[5] = $f5 ^ $x5;
+        $f[6] = $f6 ^ $x6;
+        $f[7] = $f7 ^ $x7;
+        $f[8] = $f8 ^ $x8;
+        $f[9] = $f9 ^ $x9;
+        $g[0] = $g0 ^ $x0;
+        $g[1] = $g1 ^ $x1;
+        $g[2] = $g2 ^ $x2;
+        $g[3] = $g3 ^ $x3;
+        $g[4] = $g4 ^ $x4;
+        $g[5] = $g5 ^ $x5;
+        $g[6] = $g6 ^ $x6;
+        $g[7] = $g7 ^ $x7;
+        $g[8] = $g8 ^ $x8;
+        $g[9] = $g9 ^ $x9;
+    }
+
+    /**
+     * @internal You should not use this directly from another application
+     *
+     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
+     * @return ParagonIE_Sodium_Core_Curve25519_Fe
+     */
+    public static function fe_mul121666(ParagonIE_Sodium_Core_Curve25519_Fe $f)
+    {
+        $h = array(
+            self::mul((int) $f[0], 121666, 17),
+            self::mul((int) $f[1], 121666, 17),
+            self::mul((int) $f[2], 121666, 17),
+            self::mul((int) $f[3], 121666, 17),
+            self::mul((int) $f[4], 121666, 17),
+            self::mul((int) $f[5], 121666, 17),
+            self::mul((int) $f[6], 121666, 17),
+            self::mul((int) $f[7], 121666, 17),
+            self::mul((int) $f[8], 121666, 17),
+            self::mul((int) $f[9], 121666, 17)
+        );
+
+        /** @var int $carry9 */
+        $carry9 = ($h[9] + (1 << 24)) >> 25;
+        $h[0] += self::mul($carry9, 19, 5);
+        $h[9] -= $carry9 << 25;
+        /** @var int $carry1 */
+        $carry1 = ($h[1] + (1 << 24)) >> 25;
+        $h[2] += $carry1;
+        $h[1] -= $carry1 << 25;
+        /** @var int $carry3 */
+        $carry3 = ($h[3] + (1 << 24)) >> 25;
+        $h[4] += $carry3;
+        $h[3] -= $carry3 << 25;
+        /** @var int $carry5 */
+        $carry5 = ($h[5] + (1 << 24)) >> 25;
+        $h[6] += $carry5;
+        $h[5] -= $carry5 << 25;
+        /** @var int $carry7 */
+        $carry7 = ($h[7] + (1 << 24)) >> 25;
+        $h[8] += $carry7;
+        $h[7] -= $carry7 << 25;
+
+        /** @var int $carry0 */
+        $carry0 = ($h[0] + (1 << 25)) >> 26;
+        $h[1] += $carry0;
+        $h[0] -= $carry0 << 26;
+        /** @var int $carry2 */
+        $carry2 = ($h[2] + (1 << 25)) >> 26;
+        $h[3] += $carry2;
+        $h[2] -= $carry2 << 26;
+        /** @var int $carry4 */
+        $carry4 = ($h[4] + (1 << 25)) >> 26;
+        $h[5] += $carry4;
+        $h[4] -= $carry4 << 26;
+        /** @var int $carry6 */
+        $carry6 = ($h[6] + (1 << 25)) >> 26;
+        $h[7] += $carry6;
+        $h[6] -= $carry6 << 26;
+        /** @var int $carry8 */
+        $carry8 = ($h[8] + (1 << 25)) >> 26;
+        $h[9] += $carry8;
+        $h[8] -= $carry8 << 26;
+
+        foreach ($h as $i => $value) {
+            $h[$i] = (int) $value;
+        }
+        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($h);
+    }
+
+    /**
+     * @internal You should not use this directly from another application
+     *
+     * Inline comments preceded by # are from libsodium's ref10 code.
+     *
+     * @param string $n
+     * @param string $p
+     * @return string
+     * @throws SodiumException
+     * @throws TypeError
+     */
+    public static function crypto_scalarmult_curve25519_ref10($n, $p)
+    {
+        # for (i = 0;i < 32;++i) e[i] = n[i];
+        $e = '' . $n;
+        # e[0] &= 248;
+        $e[0] = self::intToChr(
+            self::chrToInt($e[0]) & 248
+        );
+        # e[31] &= 127;
+        # e[31] |= 64;
+        $e[31] = self::intToChr(
+            (self::chrToInt($e[31]) & 127) | 64
+        );
+        # fe_frombytes(x1,p);
+        $x1 = self::fe_frombytes($p);
+        # fe_1(x2);
+        $x2 = self::fe_1();
+        # fe_0(z2);
+        $z2 = self::fe_0();
+        # fe_copy(x3,x1);
+        $x3 = self::fe_copy($x1);
+        # fe_1(z3);
+        $z3 = self::fe_1();
+
+        # swap = 0;
+        /** @var int $swap */
+        $swap = 0;
+
+        # for (pos = 254;pos >= 0;--pos) {
+        for ($pos = 254; $pos >= 0; --$pos) {
+            # b = e[pos / 8] >> (pos & 7);
+            /** @var int $b */
+            $b = self::chrToInt(
+                    $e[(int) floor($pos / 8)]
+                ) >> ($pos & 7);
+            # b &= 1;
+            $b &= 1;
+            # swap ^= b;
+            $swap ^= $b;
+            # fe_cswap(x2,x3,swap);
+            self::fe_cswap($x2, $x3, $swap);
+            # fe_cswap(z2,z3,swap);
+            self::fe_cswap($z2, $z3, $swap);
+            # swap = b;
+            $swap = $b;
+            # fe_sub(tmp0,x3,z3);
+            $tmp0 = self::fe_sub($x3, $z3);
+            # fe_sub(tmp1,x2,z2);
+            $tmp1 = self::fe_sub($x2, $z2);
+
+            # fe_add(x2,x2,z2);
+            $x2 = self::fe_add($x2, $z2);
+
+            # fe_add(z2,x3,z3);
+            $z2 = self::fe_add($x3, $z3);
+
+            # fe_mul(z3,tmp0,x2);
+            $z3 = self::fe_mul($tmp0, $x2);
+
+            # fe_mul(z2,z2,tmp1);
+            $z2 = self::fe_mul($z2, $tmp1);
+
+            # fe_sq(tmp0,tmp1);
+            $tmp0 = self::fe_sq($tmp1);
+
+            # fe_sq(tmp1,x2);
+            $tmp1 = self::fe_sq($x2);
+
+            # fe_add(x3,z3,z2);
+            $x3 = self::fe_add($z3, $z2);
+
+            # fe_sub(z2,z3,z2);
+            $z2 = self::fe_sub($z3, $z2);
+
+            # fe_mul(x2,tmp1,tmp0);
+            $x2 = self::fe_mul($tmp1, $tmp0);
+
+            # fe_sub(tmp1,tmp1,tmp0);
+            $tmp1 = self::fe_sub($tmp1, $tmp0);
+
+            # fe_sq(z2,z2);
+            $z2 = self::fe_sq($z2);
+
+            # fe_mul121666(z3,tmp1);
+            $z3 = self::fe_mul121666($tmp1);
+
+            # fe_sq(x3,x3);
+            $x3 = self::fe_sq($x3);
+
+            # fe_add(tmp0,tmp0,z3);
+            $tmp0 = self::fe_add($tmp0, $z3);
+
+            # fe_mul(z3,x1,z2);
+            $z3 = self::fe_mul($x1, $z2);
+
+            # fe_mul(z2,tmp1,tmp0);
+            $z2 = self::fe_mul($tmp1, $tmp0);
+        }
+
+        # fe_cswap(x2,x3,swap);
+        self::fe_cswap($x2, $x3, $swap);
+
+        # fe_cswap(z2,z3,swap);
+        self::fe_cswap($z2, $z3, $swap);
+
+        # fe_invert(z2,z2);
+        $z2 = self::fe_invert($z2);
+
+        # fe_mul(x2,x2,z2);
+        $x2 = self::fe_mul($x2, $z2);
+        # fe_tobytes(q,x2);
+        return self::fe_tobytes($x2);
+    }
+
+    /**
+     * @internal You should not use this directly from another application
+     *
+     * @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY
+     * @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
+     * @return ParagonIE_Sodium_Core_Curve25519_Fe
+     */
+    public static function edwards_to_montgomery(
+        ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY,
+        ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
+    ) {
+        $tempX = self::fe_add($edwardsZ, $edwardsY);
+        $tempZ = self::fe_sub($edwardsZ, $edwardsY);
+        $tempZ = self::fe_invert($tempZ);
+        return self::fe_mul($tempX, $tempZ);
+    }
+
+    /**
+     * @internal You should not use this directly from another application
+     *
+     * @param string $n
+     * @return string
+     * @throws SodiumException
+     * @throws TypeError
+     */
+    public static function crypto_scalarmult_curve25519_ref10_base($n)
+    {
+        # for (i = 0;i < 32;++i) e[i] = n[i];
+        $e = '' . $n;
+
+        # e[0] &= 248;
+        $e[0] = self::intToChr(
+            self::chrToInt($e[0]) & 248
+        );
+
+        # e[31] &= 127;
+        # e[31] |= 64;
+        $e[31] = self::intToChr(
+            (self::chrToInt($e[31]) & 127) | 64
+        );
+
+        $A = self::ge_scalarmult_base($e);
+        if (
+            !($A->Y instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
+                ||
+            !($A->Z instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
+        ) {
+            throw new TypeError('Null points encountered');
+        }
+        $pk = self::edwards_to_montgomery($A->Y, $A->Z);
+        return self::fe_tobytes($pk);
+    }
+}