diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 4511109..a415631 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -668,7 +668,14 @@
 endif
 
 ifeq ($(SODIUM),yes)
+ ifndef DYNAMIC_SODIUM
+DYNAMIC_SODIUM=yes
+ endif
+ ifeq ($(DYNAMIC_SODIUM),yes)
+DEFINES += -DDYNAMIC_SODIUM
+ else
 SODIUMLIB = -lsodium
+ endif
 endif
 
 # Only allow XPM for a GUI build.
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index b33d24b..6889a91 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -42,10 +42,10 @@
 #	Sound support: SOUND=yes (default is yes)
 #
 #	Sodium support: SODIUM=[Path to Sodium directory]
-#	 Dynamic built with libsodium
-#	 You need to install the msvc package from
-#	 https://download.libsodium.org/libsodium/releases/
-#	 and package the libsodium.dll with Vim
+#	  DYNAMIC_SODIUM=yes (to load the Sodium DLL dynamically)
+#	  You need to install the msvc package from
+#	  https://download.libsodium.org/libsodium/releases/
+#	  and package the libsodium.dll with Vim
 #
 #
 #	DLL support (EXPERIMENTAL): VIMDLL=yes (default is no)
@@ -384,6 +384,9 @@
 !ifndef SODIUM
 SODIUM = no
 !endif
+!ifndef DYNAMIC_SODIUM
+DYNAMIC_SODIUM = yes
+!endif
 
 !if "$(SODIUM)" != "no"
 ! if "$(CPU)" == "AMD64"
@@ -397,8 +400,13 @@
 
 !if "$(SODIUM)" != "no"
 SOD_INC		= /I "$(SODIUM)\include"
+! if "$(DYNAMIC_SODIUM)" == "yes"
+SOD_DEFS	= -DHAVE_SODIUM -DDYNAMIC_SODIUM
+SOD_LIB		=
+! else
 SOD_DEFS	= -DHAVE_SODIUM
 SOD_LIB		= $(SOD_LIB)\libsodium.lib
+! endif
 !endif
 
 !ifndef NETBEANS
diff --git a/src/buffer.c b/src/buffer.c
index 08db0fc..18aa2a0 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2269,8 +2269,9 @@
 #endif
 #ifdef FEAT_CRYPT
 # ifdef FEAT_SODIUM
-    if (buf->b_p_key != NULL && (crypt_get_method_nr(buf) == CRYPT_M_SOD))
-	sodium_munlock(buf->b_p_key, STRLEN(buf->b_p_key));
+    if ((buf->b_p_key != NULL) && (*buf->b_p_key != NUL) &&
+				(crypt_get_method_nr(buf) == CRYPT_M_SOD))
+	crypt_sodium_munlock(buf->b_p_key, STRLEN(buf->b_p_key));
 # endif
     clear_string_option(&buf->b_p_key);
 #endif
diff --git a/src/crypt.c b/src/crypt.c
index 85ff33a..e5d0d91 100644
--- a/src/crypt.c
+++ b/src/crypt.c
@@ -159,6 +159,108 @@
     crypto_secretstream_xchacha20poly1305_state
 		    state;
 } sodium_state_T;
+
+
+# ifdef DYNAMIC_SODIUM
+#  define sodium_init	    load_sodium
+#  define sodium_free	    dll_sodium_free
+#  define sodium_malloc	    dll_sodium_malloc
+#  define sodium_memzero    dll_sodium_memzero
+#  define sodium_mlock	    dll_sodium_mlock
+#  define sodium_munlock    dll_sodium_munlock
+#  define crypto_secretstream_xchacha20poly1305_init_push \
+    dll_crypto_secretstream_xchacha20poly1305_init_push
+#  define crypto_secretstream_xchacha20poly1305_push \
+    dll_crypto_secretstream_xchacha20poly1305_push
+#  define crypto_secretstream_xchacha20poly1305_init_pull \
+    dll_crypto_secretstream_xchacha20poly1305_init_pull
+#  define crypto_secretstream_xchacha20poly1305_pull \
+    dll_crypto_secretstream_xchacha20poly1305_pull
+#  define crypto_pwhash	    dll_crypto_pwhash
+#  define randombytes_buf   dll_randombytes_buf
+
+static int (*dll_sodium_init)(void) = NULL;
+static void (*dll_sodium_free)(void *) = NULL;
+static void *(*dll_sodium_malloc)(const size_t) = NULL;
+static void (*dll_sodium_memzero)(void * const, const size_t) = NULL;
+static int (*dll_sodium_mlock)(void * const, const size_t) = NULL;
+static int (*dll_sodium_munlock)(void * const, const size_t) = NULL;
+static int (*dll_crypto_secretstream_xchacha20poly1305_init_push)
+   (crypto_secretstream_xchacha20poly1305_state *state,
+    unsigned char [],
+    const unsigned char []) = NULL;
+static int (*dll_crypto_secretstream_xchacha20poly1305_push)
+   (crypto_secretstream_xchacha20poly1305_state *state,
+    unsigned char *c, unsigned long long *clen_p,
+    const unsigned char *m, unsigned long long mlen,
+    const unsigned char *ad, unsigned long long adlen, unsigned char tag)
+    = NULL;
+static int (*dll_crypto_secretstream_xchacha20poly1305_init_pull)
+   (crypto_secretstream_xchacha20poly1305_state *state,
+    const unsigned char [],
+    const unsigned char []) = NULL;
+static int (*dll_crypto_secretstream_xchacha20poly1305_pull)
+   (crypto_secretstream_xchacha20poly1305_state *state,
+    unsigned char *m, unsigned long long *mlen_p, unsigned char *tag_p,
+    const unsigned char *c, unsigned long long clen,
+    const unsigned char *ad, unsigned long long adlen) = NULL;
+static int (*dll_crypto_pwhash)(unsigned char * const out,
+    unsigned long long outlen,
+    const char * const passwd, unsigned long long passwdlen,
+    const unsigned char * const salt,
+    unsigned long long opslimit, size_t memlimit, int alg)
+    = NULL;
+static void (*dll_randombytes_buf)(void * const buf, const size_t size);
+
+static struct {
+    const char *name;
+    FARPROC *ptr;
+} sodium_funcname_table[] = {
+    {"sodium_init", (FARPROC*)&dll_sodium_init},
+    {"sodium_free", (FARPROC*)&dll_sodium_free},
+    {"sodium_malloc", (FARPROC*)&dll_sodium_malloc},
+    {"sodium_memzero", (FARPROC*)&dll_sodium_memzero},
+    {"sodium_mlock", (FARPROC*)&dll_sodium_mlock},
+    {"sodium_munlock", (FARPROC*)&dll_sodium_munlock},
+    {"crypto_secretstream_xchacha20poly1305_init_push", (FARPROC*)&dll_crypto_secretstream_xchacha20poly1305_init_push},
+    {"crypto_secretstream_xchacha20poly1305_push", (FARPROC*)&dll_crypto_secretstream_xchacha20poly1305_push},
+    {"crypto_secretstream_xchacha20poly1305_init_pull", (FARPROC*)&dll_crypto_secretstream_xchacha20poly1305_init_pull},
+    {"crypto_secretstream_xchacha20poly1305_pull", (FARPROC*)&dll_crypto_secretstream_xchacha20poly1305_pull},
+    {"crypto_pwhash", (FARPROC*)&dll_crypto_pwhash},
+    {"randombytes_buf", (FARPROC*)&dll_randombytes_buf},
+    {NULL, NULL}
+};
+
+    static int
+load_sodium(void)
+{
+    static HANDLE hsodium = NULL;
+    int i;
+
+    if (hsodium != NULL)
+	return 0;
+
+    hsodium = vimLoadLib("libsodium.dll");
+    if (hsodium == NULL)
+    {
+	// TODO: Show error message.
+	return -1;
+    }
+
+    for (i = 0; sodium_funcname_table[i].ptr; ++i)
+    {
+	if ((*sodium_funcname_table[i].ptr = GetProcAddress(hsodium,
+			sodium_funcname_table[i].name)) == NULL)
+	{
+	    FreeLibrary(hsodium);
+	    hsodium = NULL;
+	    // TODO: Show error message.
+	    return -1;
+	}
+    }
+    return dll_sodium_init();
+}
+# endif
 #endif
 
 #define CRYPT_MAGIC_LEN	12	// cannot change
@@ -990,4 +1092,18 @@
 # endif
 }
 
+# if defined(FEAT_SODIUM) || defined(PROTO)
+    int
+crypt_sodium_munlock(void *const addr, const size_t len)
+{
+    return sodium_munlock(addr, len);
+}
+
+    void
+crypt_sodium_randombytes_buf(void *const buf, const size_t size)
+{
+    randombytes_buf(buf, size);
+}
+# endif
+
 #endif // FEAT_CRYPT
diff --git a/src/memline.c b/src/memline.c
index a42c5f1..56f6958 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -436,7 +436,8 @@
 	}
 #ifdef FEAT_SODIUM
 	else if (method_nr == CRYPT_M_SOD)
-	    randombytes_buf(buf->b_ml.ml_mfp->mf_seed, MF_SEED_LEN);
+	    crypt_sodium_randombytes_buf(buf->b_ml.ml_mfp->mf_seed,
+							    MF_SEED_LEN);
  #endif
     }
 }
diff --git a/src/proto/crypt.pro b/src/proto/crypt.pro
index 18382a7..682fe45 100644
--- a/src/proto/crypt.pro
+++ b/src/proto/crypt.pro
@@ -26,4 +26,6 @@
 int crypt_sodium_init(cryptstate_T *state, char_u *key, char_u *salt, int salt_len, char_u *seed, int seed_len);
 long crypt_sodium_buffer_encode(cryptstate_T *state, char_u *from, size_t len, char_u **buf_out, int last);
 long crypt_sodium_buffer_decode(cryptstate_T *state, char_u *from, size_t len, char_u **buf_out, int last);
+int crypt_sodium_munlock(void *const addr, const size_t len);
+void crypt_sodium_randombytes_buf(void *const buf, const size_t size);
 /* vim: set ft=c : */
diff --git a/src/version.c b/src/version.c
index 20a26d5..86a727f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4144,
+/**/
     4143,
 /**/
     4142,