diff --git a/auth/credentials/credentials_ntlm.c b/auth/credentials/credentials_ntlm.c
index 2d6d6f6..8f143bf 100644
--- a/auth/credentials/credentials_ntlm.c
+++ b/auth/credentials/credentials_ntlm.c
@@ -110,7 +110,7 @@ _PUBLIC_ NTSTATUS cli_credentials_get_ntlm_response(struct cli_credentials *cred
 		/* LM Key is incompatible... */
 		*flags &= ~CLI_CRED_LANMAN_AUTH;
 	} else if (*flags & CLI_CRED_NTLM2) {
-		struct MD5Context md5_session_nonce_ctx;
+		MD5_CTX md5_session_nonce_ctx;
 		uint8_t session_nonce[16];
 		uint8_t session_nonce_hash[16];
 		uint8_t user_session_key[16];
diff --git a/auth/ntlmssp/ntlmssp_server.c b/auth/ntlmssp/ntlmssp_server.c
index d9bea1c..4060428 100644
--- a/auth/ntlmssp/ntlmssp_server.c
+++ b/auth/ntlmssp/ntlmssp_server.c
@@ -369,7 +369,7 @@ static NTSTATUS ntlmssp_server_preauth(struct gensec_security *gensec_security,
 	*/
 	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 		if (ntlmssp_state->nt_resp.length == 24 && ntlmssp_state->lm_resp.length == 24) {
-			struct MD5Context md5_session_nonce_ctx;
+			MD5_CTX md5_session_nonce_ctx;
 			state->doing_ntlm2 = true;
 
 			memcpy(state->session_nonce, ntlmssp_state->internal_chal.data, 8);
diff --git a/auth/ntlmssp/ntlmssp_sign.c b/auth/ntlmssp/ntlmssp_sign.c
index 4d07a81..c0be914 100644
--- a/auth/ntlmssp/ntlmssp_sign.c
+++ b/auth/ntlmssp/ntlmssp_sign.c
@@ -51,7 +51,7 @@ static void calc_ntlmv2_key(uint8_t subkey[16],
 			    DATA_BLOB session_key,
 			    const char *constant)
 {
-	struct MD5Context ctx3;
+	MD5_CTX ctx3;
 	MD5Init(&ctx3);
 	MD5Update(&ctx3, session_key.data, session_key.length);
 	MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1);
diff --git a/lib/crypto/hmacmd5.c b/lib/crypto/hmacmd5.c
index cfbd428..2419bdb 100644
--- a/lib/crypto/hmacmd5.c
+++ b/lib/crypto/hmacmd5.c
@@ -36,7 +36,7 @@ _PUBLIC_ void hmac_md5_init_rfc2104(const uint8_t *key, int key_len, HMACMD5Cont
         /* if key is longer than 64 bytes reset it to key=MD5(key) */
         if (key_len > 64)
 	{
-                struct MD5Context tctx;
+		MD5_CTX tctx;
 
                 MD5Init(&tctx);
                 MD5Update(&tctx, key, key_len);
@@ -91,7 +91,7 @@ _PUBLIC_ void hmac_md5_update(const uint8_t *text, int text_len, HMACMD5Context
 ***********************************************************************/
 _PUBLIC_ void hmac_md5_final(uint8_t *digest, HMACMD5Context *ctx)
 {
-        struct MD5Context ctx_o;
+	MD5_CTX ctx_o;
 
         MD5Final(digest, &ctx->ctx);          
 
diff --git a/lib/crypto/hmacmd5.h b/lib/crypto/hmacmd5.h
index 91b8ca5..1fc2750 100644
--- a/lib/crypto/hmacmd5.h
+++ b/lib/crypto/hmacmd5.h
@@ -25,7 +25,7 @@
 
 typedef struct 
 {
-        struct MD5Context ctx;
+	MD5_CTX ctx;
         uint8_t k_ipad[65];    
         uint8_t k_opad[65];
 
diff --git a/lib/crypto/md5.h b/lib/crypto/md5.h
index 388cdf8..4467a34 100644
--- a/lib/crypto/md5.h
+++ b/lib/crypto/md5.h
@@ -6,6 +6,14 @@
 #define HEADER_MD5_H 
 #endif
 
+#ifdef HAVE_MD5_H
+/*
+ * Try to avoid clashes with Solaris MD5 implementation.
+ * ...where almost all implementations follows:
+ * Schneier's: "Cryptography Classics Library"
+ */
+#include <md5.h>
+#else /* !HAVE_MD5_H */
 #ifdef HAVE_BSD_MD5_H
 /* Try to avoid clashes with BSD MD5 implementation */
 #include <bsd/md5.h>
@@ -18,8 +26,9 @@
 #define MD5Update(c,d,l)			CC_MD5_Update(c,d,l)
 #define MD5Final(m, c)				CC_MD5_Final((unsigned char *)m,c)
 #define MD5Context CC_MD5state_st
+typedef struct MD5Context MD5_CTX;
 
-#else
+#else /* have nothing other, use Samba internal MD5 */
 typedef struct MD5Context {
 	uint32_t buf[4];
 	uint32_t bits[2];
@@ -32,8 +41,10 @@ void MD5Init(MD5_CTX *context);
 void MD5Update(MD5_CTX *context, const uint8_t *buf,
 	       size_t len);
 void MD5Final(uint8_t digest[MD5_DIGEST_LENGTH], MD5_CTX *context);
-#endif /* HAVE_COMMONCRYPTO_COMMONDIGEST_H */
+#endif /* have nothing other, use Samba internal MD5 */
 
 #endif /* HAVE_BSD_MD5_H */
 
+#endif /* HAVE_MD5_H */
+
 #endif /* !MD5_H */
diff --git a/lib/crypto/md5test.c b/lib/crypto/md5test.c
index 38626c3..f58e131 100644
--- a/lib/crypto/md5test.c
+++ b/lib/crypto/md5test.c
@@ -65,7 +65,7 @@ bool torture_local_crypto_md5(struct torture_context *torture)
 	};
 
 	for (i=0; i < ARRAY_SIZE(testarray); i++) {
-		struct MD5Context ctx;
+		MD5_CTX ctx;
 		uint8_t md5[16];
 		int e;
 
diff --git a/libcli/auth/credentials.c b/libcli/auth/credentials.c
index dfbfdb3..28b46db 100644
--- a/libcli/auth/credentials.c
+++ b/libcli/auth/credentials.c
@@ -79,7 +79,7 @@ static void netlogon_creds_init_128bit(struct netlogon_creds_CredentialState *cr
 {
 	unsigned char zero[4], tmp[16];
 	HMACMD5Context ctx;
-	struct MD5Context md5;
+	MD5_CTX md5;
 
 	ZERO_STRUCT(creds->session_key);
 
diff --git a/libcli/auth/smbencrypt.c b/libcli/auth/smbencrypt.c
index 37d5672..b1ca1ba 100644
--- a/libcli/auth/smbencrypt.c
+++ b/libcli/auth/smbencrypt.c
@@ -99,7 +99,7 @@ bool E_md4hash(const char *passwd, uint8_t p16[16])
 
 void E_md5hash(const uint8_t salt[16], const uint8_t nthash[16], uint8_t hash_out[16])
 {
-	struct MD5Context tctx;
+	MD5_CTX tctx;
 	MD5Init(&tctx);
 	MD5Update(&tctx, salt, 16);
 	MD5Update(&tctx, nthash, 16);
@@ -646,7 +646,7 @@ bool decode_pw_buffer(TALLOC_CTX *ctx,
 
 void encode_or_decode_arc4_passwd_buffer(unsigned char pw_buf[532], const DATA_BLOB *psession_key)
 {
-	struct MD5Context tctx;
+	MD5_CTX tctx;
 	unsigned char key_out[16];
 
 	/* Confounder is last 16 bytes. */
@@ -726,7 +726,7 @@ void encode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
 					struct wkssvc_PasswordBuffer **pwd_buf)
 {
 	uint8_t buffer[516];
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	struct wkssvc_PasswordBuffer *my_pwd_buf = NULL;
 	DATA_BLOB confounded_session_key;
 	int confounder_len = 8;
@@ -764,7 +764,7 @@ WERROR decode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
 					  char **pwd)
 {
 	uint8_t buffer[516];
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	size_t pwd_len;
 
 	DATA_BLOB confounded_session_key;
diff --git a/libcli/drsuapi/repl_decrypt.c b/libcli/drsuapi/repl_decrypt.c
index 6fff2fe..00b8db8 100644
--- a/libcli/drsuapi/repl_decrypt.c
+++ b/libcli/drsuapi/repl_decrypt.c
@@ -39,7 +39,7 @@ WERROR drsuapi_decrypt_attribute_value(TALLOC_CTX *mem_ctx,
 	DATA_BLOB confounder;
 	DATA_BLOB enc_buffer;
 
-	struct MD5Context md5;
+	MD5_CTX md5;
 	uint8_t _enc_key[16];
 	DATA_BLOB enc_key;
 
@@ -198,7 +198,7 @@ static WERROR drsuapi_encrypt_attribute_value(TALLOC_CTX *mem_ctx,
 	DATA_BLOB rid_crypt_out = data_blob(NULL, 0);
 	DATA_BLOB confounder;
 
-	struct MD5Context md5;
+	MD5_CTX md5;
 	uint8_t _enc_key[16];
 	DATA_BLOB enc_key;
 
diff --git a/libcli/smb/smb_signing.c b/libcli/smb/smb_signing.c
index a72760b..134b759 100644
--- a/libcli/smb/smb_signing.c
+++ b/libcli/smb/smb_signing.c
@@ -145,7 +145,7 @@ static void smb_signing_md5(const DATA_BLOB *mac_key,
 {
 	const size_t offset_end_of_sig = (NBT_HDR_SIZE + HDR_SS_FIELD + 8);
 	uint8_t sequence_buf[8];
-	struct MD5Context md5_ctx;
+	MD5_CTX md5_ctx;
 
 	/*
 	 * Firstly put the sequence number into the first 4 bytes.
diff --git a/source3/configure.in b/source3/configure.in
index bd21db9..afd1f32 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -611,20 +611,38 @@ AC_CHECK_HEADERS(langinfo.h locale.h)
 AC_CHECK_HEADERS(xfs/libxfs.h)
 AC_CHECK_HEADERS(netgroup.h)
 AC_CHECK_HEADERS(linux/falloc.h)
+AC_CHECK_HEADERS(md5.h)
 AC_CHECK_HEADERS(CommonCrypto/CommonDigest.h)
 
-AC_CHECK_HEADERS(rpcsvc/yp_prot.h,,,[[
-#if HAVE_RPC_RPC_H
-#include <rpc/rpc.h>
-#endif
-]])
-CRYPTO_MD5_OBJ=
 if test "x$ac_cv_header_CommonCrypto_CommonDigest_h" != "xyes"
+    dnl CommonCrypto/CommonDigest.h on MacOS
+    CRYPTO_MD5_OBJ=
 then
+    dnl check for OS implementation of md5 conformant to rfc1321
+    if test x"$ac_cv_header_md5_h" = x"yes"; then
+	AC_DEFINE(HAVE_MD5_H, 1,
+		[Whether md5.h is available.])
+	AC_CHECK_LIB(md5, MD5Update,
+	    [
+		LIBS="${LIBS} -lmd5"
+		CRYPTO_MD5_OBJ=
+		AC_DEFINE(HAVE_LIBMD5, 1,
+		    [Whether libmd5 conformant to rfc1321 is available.])],
+	    [
+	CRYPTO_MD5_OBJ="../lib/crypto/md5.o"])
+    else
+	dnl There is no rfc1321 md5.h nor CommonDigest.h library so we make the Samba one
 	CRYPTO_MD5_OBJ="../lib/crypto/md5.o"
+    fi
 fi
 AC_SUBST(CRYPTO_MD5_OBJ)
 
+AC_CHECK_HEADERS(rpcsvc/yp_prot.h,,,[[
+#if HAVE_RPC_RPC_H
+#include <rpc/rpc.h>
+#endif
+]])
+
 ## These fail to compile on IRIX so just check for their presence
 AC_CHECK_HEADERS(sys/mode.h,,,)
 
diff --git a/source3/libsmb/ntlmssp.c b/source3/libsmb/ntlmssp.c
index fb41c3c..9abd38f 100644
--- a/source3/libsmb/ntlmssp.c
+++ b/source3/libsmb/ntlmssp.c
@@ -537,7 +537,7 @@ noccache:
 			return NT_STATUS_NO_MEMORY;
 		}
 	} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
-		struct MD5Context md5_session_nonce_ctx;
+		MD5_CTX md5_session_nonce_ctx;
 		uint8_t session_nonce[16];
 		uint8_t session_nonce_hash[16];
 		uint8_t user_session_key[16];
diff --git a/source3/modules/vfs_streams_xattr.c b/source3/modules/vfs_streams_xattr.c
index 291531e..e5ddc17 100644
--- a/source3/modules/vfs_streams_xattr.c
+++ b/source3/modules/vfs_streams_xattr.c
@@ -39,7 +39,7 @@ struct stream_io {
 
 static SMB_INO_T stream_inode(const SMB_STRUCT_STAT *sbuf, const char *sname)
 {
-	struct MD5Context ctx;
+	MD5_CTX ctx;
         unsigned char hash[16];
 	SMB_INO_T result;
 	char *upper_sname;
diff --git a/source3/rpc_client/init_samr.c b/source3/rpc_client/init_samr.c
index e3bb301..7f1a229 100644
--- a/source3/rpc_client/init_samr.c
+++ b/source3/rpc_client/init_samr.c
@@ -34,7 +34,7 @@ void init_samr_CryptPasswordEx(const char *pwd,
 	/* samr_CryptPasswordEx */
 
 	uchar pwbuf[532];
-	struct MD5Context md5_ctx;
+	MD5_CTX md5_ctx;
 	uint8_t confounder[16];
 	DATA_BLOB confounded_session_key = data_blob(NULL, 16);
 
diff --git a/source3/web/swat.c b/source3/web/swat.c
index 90e4af9..d60eca8 100644
--- a/source3/web/swat.c
+++ b/source3/web/swat.c
@@ -153,7 +153,7 @@ static char *make_parm_name(const char *label)
 void get_xsrf_token(const char *username, const char *pass,
 		    const char *formname, time_t xsrf_time, char token_str[33])
 {
-	struct MD5Context md5_ctx;
+	MD5_CTX md5_ctx;
 	uint8_t token[16];
 	int i;
 
diff --git a/source4/dsdb/samdb/ldb_modules/password_hash.c b/source4/dsdb/samdb/ldb_modules/password_hash.c
index 620de75..3254e1e 100644
--- a/source4/dsdb/samdb/ldb_modules/password_hash.c
+++ b/source4/dsdb/samdb/ldb_modules/password_hash.c
@@ -1368,7 +1368,7 @@ static int setup_primary_wdigest(struct setup_password_fields_io *io,
 	}
 
 	for (i=0; i < ARRAY_SIZE(wdigest); i++) {
-		struct MD5Context md5;
+		MD5_CTX md5;
 		MD5Init(&md5);
 		if (wdigest[i].nt4dom) {
 			MD5Update(&md5, wdigest[i].nt4dom->data, wdigest[i].nt4dom->length);
diff --git a/source4/libcli/raw/smb_signing.c b/source4/libcli/raw/smb_signing.c
index 5d2f928..405efab 100644
--- a/source4/libcli/raw/smb_signing.c
+++ b/source4/libcli/raw/smb_signing.c
@@ -81,7 +81,7 @@ bool signing_good(struct smb_signing_context *sign_info,
 void sign_outgoing_message(struct smb_request_buffer *out, DATA_BLOB *mac_key, unsigned int seq_num) 
 {
 	uint8_t calc_md5_mac[16];
-	struct MD5Context md5_ctx;
+	MD5_CTX md5_ctx;
 
 	/*
 	 * Firstly put the sequence number into the first 4 bytes.
@@ -116,7 +116,7 @@ bool check_signed_incoming_message(struct smb_request_buffer *in, DATA_BLOB *mac
 	uint8_t calc_md5_mac[16];
 	uint8_t *server_sent_mac;
 	uint8_t sequence_buf[8];
-	struct MD5Context md5_ctx;
+	MD5_CTX md5_ctx;
 	const size_t offset_end_of_sig = (HDR_SS_FIELD + 8);
 	int i;
 	const int sign_range = 0;
diff --git a/source4/libnet/libnet_passwd.c b/source4/libnet/libnet_passwd.c
index e1094f2..861d746 100644
--- a/source4/libnet/libnet_passwd.c
+++ b/source4/libnet/libnet_passwd.c
@@ -274,7 +274,7 @@ static NTSTATUS libnet_SetPassword_samr_handle_26(struct libnet_context *ctx, TA
 	DATA_BLOB session_key;
 	DATA_BLOB confounded_session_key = data_blob_talloc(mem_ctx, NULL, 16);
 	uint8_t confounder[16];	
-	struct MD5Context md5;
+	MD5_CTX md5;
 
 	if (r->samr_handle.in.info21) {
 		return NT_STATUS_INVALID_PARAMETER_MIX;
@@ -330,7 +330,7 @@ static NTSTATUS libnet_SetPassword_samr_handle_25(struct libnet_context *ctx, TA
 	DATA_BLOB session_key;
 	DATA_BLOB confounded_session_key = data_blob_talloc(mem_ctx, NULL, 16);
 	uint8_t confounder[16];	
-	struct MD5Context md5;
+	MD5_CTX md5;
 
 	if (!r->samr_handle.in.info21) {
 		return NT_STATUS_INVALID_PARAMETER_MIX;
diff --git a/source4/ntp_signd/ntp_signd.c b/source4/ntp_signd/ntp_signd.c
index c6d6056..0b994f3 100644
--- a/source4/ntp_signd/ntp_signd.c
+++ b/source4/ntp_signd/ntp_signd.c
@@ -109,7 +109,7 @@ static NTSTATUS ntp_signd_process(struct ntp_signd_connection *ntp_signd_conn,
 	enum ndr_err_code ndr_err;
 	struct ldb_result *res;
 	const char *attrs[] = { "unicodePwd", "userAccountControl", "cn", NULL };
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	struct samr_Password *nt_hash;
 	uint32_t user_account_control;
 	int ret;
diff --git a/source4/rpc_server/samr/samr_password.c b/source4/rpc_server/samr/samr_password.c
index 8963b04..379c75d 100644
--- a/source4/rpc_server/samr/samr_password.c
+++ b/source4/rpc_server/samr/samr_password.c
@@ -548,7 +548,7 @@ NTSTATUS samr_set_password_ex(struct dcesrv_call_state *dce_call,
 	DATA_BLOB new_password;
 	DATA_BLOB co_session_key;
 	DATA_BLOB session_key = data_blob(NULL, 0);
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 
 	nt_status = dcesrv_fetch_session_key(dce_call->conn, &session_key);
 	if (!NT_STATUS_IS_OK(nt_status)) {
diff --git a/source4/torture/ntp/ntp_signd.c b/source4/torture/ntp/ntp_signd.c
index ce49d4f..89eb1a0 100644
--- a/source4/torture/ntp/ntp_signd.c
+++ b/source4/torture/ntp/ntp_signd.c
@@ -78,7 +78,7 @@ static bool test_ntp_signd(struct torture_context *tctx,
 	char *unix_address;
 	int sys_errno;
 
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	uint8_t sig[16];
 	enum ndr_err_code ndr_err;
 	bool ok;
diff --git a/source4/torture/rpc/samba3rpc.c b/source4/torture/rpc/samba3rpc.c
index 2a905ea..8fd9c4e 100644
--- a/source4/torture/rpc/samba3rpc.c
+++ b/source4/torture/rpc/samba3rpc.c
@@ -777,7 +777,7 @@ static bool join3(struct torture_context *tctx,
 		DATA_BLOB session_key;
 		DATA_BLOB confounded_session_key = data_blob_talloc(
 			mem_ctx, NULL, 16);
-		struct MD5Context ctx;
+		MD5_CTX ctx;
 		uint8_t confounder[16];
 
 		ZERO_STRUCT(u_info);
diff --git a/source4/torture/rpc/samlogon.c b/source4/torture/rpc/samlogon.c
index 640bd6a..207224a 100644
--- a/source4/torture/rpc/samlogon.c
+++ b/source4/torture/rpc/samlogon.c
@@ -1077,7 +1077,7 @@ static bool test_ntlm2(struct samlogon_state *samlogon_state, char **error_strin
 	uint8_t session_nonce_hash[16];
 	uint8_t client_chall[8];
 
-	struct MD5Context md5_session_nonce_ctx;
+	MD5_CTX md5_session_nonce_ctx;
 	HMACMD5Context hmac_ctx;
 
 	ZERO_STRUCT(user_session_key);
diff --git a/source4/torture/rpc/samr.c b/source4/torture/rpc/samr.c
index a460211..fd372cf 100644
--- a/source4/torture/rpc/samr.c
+++ b/source4/torture/rpc/samr.c
@@ -772,7 +772,7 @@ static bool test_SetUserPassEx(struct dcerpc_pipe *p, struct torture_context *tc
 	uint8_t confounder[16];
 	char *newpass;
 	struct dcerpc_binding_handle *b = p->binding_handle;
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	struct samr_GetUserPwInfo pwp;
 	struct samr_PwInfo info;
 	int policy_min_pw_len = 0;
@@ -857,7 +857,7 @@ static bool test_SetUserPass_25(struct dcerpc_pipe *p, struct torture_context *t
 	bool ret = true;
 	DATA_BLOB session_key;
 	DATA_BLOB confounded_session_key = data_blob_talloc(tctx, NULL, 16);
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	uint8_t confounder[16];
 	char *newpass;
 	struct dcerpc_binding_handle *b = p->binding_handle;
@@ -1141,7 +1141,7 @@ static bool test_SetUserPass_level_ex(struct dcerpc_pipe *p,
 	bool ret = true;
 	DATA_BLOB session_key;
 	DATA_BLOB confounded_session_key = data_blob_talloc(tctx, NULL, 16);
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 	uint8_t confounder[16];
 	char *newpass;
 	struct dcerpc_binding_handle *b = p->binding_handle;
@@ -2459,7 +2459,7 @@ bool test_ChangePasswordRandomBytes(struct dcerpc_pipe *p, struct torture_contex
 	DATA_BLOB session_key;
 	DATA_BLOB confounded_session_key = data_blob_talloc(tctx, NULL, 16);
 	uint8_t confounder[16];
-	struct MD5Context ctx;
+	MD5_CTX ctx;
 
 	bool ret = true;
 	struct lsa_String server, account;