diff --git a/ChangeLog b/ChangeLog
index 2fa6789f9b..dfb4a7cb6c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Sep 27 02:25:14 2002  Akinori MUSHA  <knu@iDaemons.org>
+
+	* ext/digest/rmd160: Use OpenSSL's RMD160 engine if available.  It
+	  is much faster than what we have now (rmd160.[ch]).  Add a knob
+	  (--with-bundled-rmd160) to extconf.rb which makes it use the
+	  bundled one anyway.
+
 Fri Sep 27 01:23:39 2002  Akinori MUSHA  <knu@iDaemons.org>
 
 	* ext/digest/md5: Use OpenSSL's MD5 engine if available.  It is
diff --git a/ext/digest/rmd160/depend b/ext/digest/rmd160/depend
index 7cf1d5e639..0ca79c5f40 100644
--- a/ext/digest/rmd160/depend
+++ b/ext/digest/rmd160/depend
@@ -5,3 +5,4 @@ rmd160hl.o: rmd160hl.c rmd160.h $(srcdir)/../defs.h $(hdrdir)/ruby.h \
 rmd160init.o: rmd160init.c $(srcdir)/../digest.h $(hdrdir)/ruby.h \
   $(topdir)/config.h $(hdrdir)/defines.h $(hdrdir)/intern.h \
   rmd160.h $(srcdir)/../defs.h
+rmd160ossl.o: rmd160ossl.h $(srcdir)/../defs.h
diff --git a/ext/digest/rmd160/extconf.rb b/ext/digest/rmd160/extconf.rb
index ce53c77b55..3f6a88e756 100644
--- a/ext/digest/rmd160/extconf.rb
+++ b/ext/digest/rmd160/extconf.rb
@@ -5,11 +5,17 @@ require "mkmf"
 
 $CFLAGS << " -DHAVE_CONFIG_H -I#{File.dirname(__FILE__)}/.."
 
-$objs = [
-  "rmd160.#{$OBJEXT}",
-  "rmd160hl.#{$OBJEXT}",
-  "rmd160init.#{$OBJEXT}",
-]
+$objs = [ "rmd160init.#{$OBJEXT}" ]
+
+dir_config("openssl")
+
+if !with_config("bundled-rmd160") &&
+    have_library("crypto") && have_header("openssl/ripemd.h")
+  $objs << "rmd160ossl.#{$OBJEXT}"
+  $libs << " -lcrypto"
+else
+  $objs << "rmd160.#{$OBJEXT}" << "rmd160hl.#{$OBJEXT}"
+end
 
 have_header("sys/cdefs.h")
 
diff --git a/ext/digest/rmd160/rmd160init.c b/ext/digest/rmd160/rmd160init.c
index 6955c2b64b..b16cdbbed8 100644
--- a/ext/digest/rmd160/rmd160init.c
+++ b/ext/digest/rmd160/rmd160init.c
@@ -2,7 +2,11 @@
 /* $Id$ */
 
 #include "digest.h"
+#if defined(HAVE_OPENSSL_RIPEMD_H)
+#include "rmd160ossl.h"
+#else
 #include "rmd160.h"
+#endif
 
 static algo_t rmd160 = {
     RMD160_DIGEST_LENGTH,
diff --git a/ext/digest/rmd160/rmd160ossl.c b/ext/digest/rmd160/rmd160ossl.c
new file mode 100644
index 0000000000..be66d81ff9
--- /dev/null
+++ b/ext/digest/rmd160/rmd160ossl.c
@@ -0,0 +1,45 @@
+/* $Id$ */
+
+#include "rmd160ossl.h"
+#include "defs.h"
+#include <assert.h>
+#include <stdlib.h>
+
+#ifndef _DIAGASSERT
+#define _DIAGASSERT(cond)	assert(cond)
+#endif
+
+char *
+RMD160_End(RMD160_CTX *ctx, char *buf)
+{
+    size_t i;
+    char *p = buf;
+    uint8_t digest[20];
+    static const char hex[]="0123456789abcdef";
+
+    _DIAGASSERT(ctx != NULL);
+    /* buf may be NULL */
+
+    if (p == NULL && (p = malloc(41)) == NULL)
+	return 0;
+
+    RMD160_Final(digest,ctx);
+    for (i = 0; i < 20; i++) {
+	p[i + i] = hex[(uint32_t)digest[i] >> 4];
+	p[i + i + 1] = hex[digest[i] & 0x0f];
+    }
+    p[i + i] = '\0';
+    return(p);
+}
+
+int RMD160_Equal(RMD160_CTX* pctx1, RMD160_CTX* pctx2) {
+	return pctx1->num == pctx2->num
+	  && pctx1->A == pctx2->A
+	  && pctx1->B == pctx2->B
+	  && pctx1->C == pctx2->C
+	  && pctx1->D == pctx2->D
+	  && pctx1->E == pctx2->E
+	  && pctx1->Nl == pctx2->Nl
+	  && pctx1->Nh == pctx2->Nh
+	  && memcmp(pctx1->data, pctx2->data, sizeof(pctx1->data)) == 0;
+}
diff --git a/ext/digest/rmd160/rmd160ossl.h b/ext/digest/rmd160/rmd160ossl.h
new file mode 100644
index 0000000000..824a1bf32f
--- /dev/null
+++ b/ext/digest/rmd160/rmd160ossl.h
@@ -0,0 +1,20 @@
+/* $Id$ */
+
+#ifndef RMD160OSSL_H_INCLUDED
+#define RMD160OSSL_H_INCLUDED
+
+#include <openssl/ripemd.h>
+
+#define RMD160_CTX	RIPEMD160_CTX
+
+#define RMD160_Init	RIPEMD160_Init
+#define RMD160_Update	RIPEMD160_Update
+#define RMD160_Final	RIPEMD160_Final
+
+#define RMD160_BLOCK_LENGTH		RIPEMD160_CBLOCK
+#define RMD160_DIGEST_LENGTH		RIPEMD160_DIGEST_LENGTH
+
+char *RMD160_End(RMD160_CTX *ctx, char *buf);
+int RMD160_Equal(RMD160_CTX *pctx1, RMD160_CTX *pctx2);
+
+#endif