diff --git a/src/libsec/port/rsatest.c b/src/libsec/port/rsatest.c
new file mode 100644
index 0000000..9ff66b5
--- /dev/null
+++ b/src/libsec/port/rsatest.c
@@ -0,0 +1,57 @@
+#include "os.h"
+#include <mp.h>
+#include <libsec.h>
+#include <bio.h>
+
+void
+main(void)
+{
+	RSApriv *rsa;
+	Biobuf b;
+	char *p;
+	int n;
+	mpint *clr, *enc, *clr2;
+	uchar buf[4096];
+	uchar *e;
+	vlong start;
+
+	fmtinstall('B', mpconv);
+
+	rsa = rsagen(1024, 16, 0);
+	if(rsa == nil)
+		sysfatal("rsagen");
+	Binit(&b, 0, OREAD);
+	clr = mpnew(0);
+	clr2 = mpnew(0);
+	enc = mpnew(0);
+
+	strtomp("123456789abcdef123456789abcdef123456789abcdef123456789abcdef", nil, 16, clr);
+	rsaencrypt(&rsa->pub, clr, enc);
+	
+	start = nsec();
+	for(n = 0; n < 10; n++)
+		rsadecrypt(rsa, enc, clr);
+	print("%lld\n", nsec()-start);
+
+	start = nsec();
+	for(n = 0; n < 10; n++)
+		mpexp(enc, rsa->dk, rsa->pub.n, clr2);
+	print("%lld\n", nsec()-start);
+
+	if(mpcmp(clr, clr2) != 0)
+		print("%B != %B\n", clr, clr2);
+	
+	print("> ");
+	while(p = Brdline(&b, '\n')){
+		n = Blinelen(&b);
+		letomp((uchar*)p, n, clr);
+		print("clr %B\n", clr);
+		rsaencrypt(&rsa->pub, clr, enc);
+		print("enc %B\n", enc);
+		rsadecrypt(rsa, enc, clr);
+		print("clr %B\n", clr);
+		n = mptole(clr, buf, sizeof(buf), nil);
+		write(1, buf, n);
+		print("> ");
+	}
+}