diff --git a/include/libsec.h b/include/libsec.h
index 96d4811..12a1cec 100644
--- a/include/libsec.h
+++ b/include/libsec.h
@@ -104,13 +104,18 @@ struct Chachastate
 		};
 	};
 	int	rounds;
+	int	ivwords;
 };
 
-void	setupChachastate(Chachastate*, uchar*, usize, uchar*, int);
-void	chacha_setblock(Chachastate*, u32int);
+void	setupChachastate(Chachastate*, uchar*, usize, uchar*, ulong, int);
+void	chacha_setiv(Chachastate *, uchar*);
+void	chacha_setblock(Chachastate*, u64int);
 void	chacha_encrypt(uchar*, usize, Chachastate*);
 void	chacha_encrypt2(uchar*, uchar*, usize, Chachastate*);
 
+void	ccpoly_encrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs);
+int	ccpoly_decrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs);
+
 /*
  * DES definitions
  */
@@ -183,6 +188,7 @@ enum
 	MD4dlen=	16,	/* MD4 digest length */
 	MD5dlen=	16,	/* MD5 digest length */
 	AESdlen=	16,	/* TODO: see rfc */
+	Poly1305dlen=	16,	/* Poly1305 digest length */
 
 	Hmacblksz	= 64,	/* in bytes; from rfc2104 */
 };
@@ -192,7 +198,7 @@ struct DigestState
 {
 	uvlong	len;
 	union {
-		u32int	state[8];
+		u32int	state[16];
 		u64int	bstate[8];
 	};
 	uchar	buf[256];
@@ -234,6 +240,8 @@ MD5state*	md5unpickle(char*);
 char*		sha1pickle(SHA1state*);
 SHA1state*	sha1unpickle(char*);
 
+DigestState*	poly1305(uchar*, ulong, uchar*, ulong, uchar*, DigestState*);
+
 /*
  * random number generation
  */
@@ -440,3 +448,14 @@ int	okThumbprint(uchar *sha1, Thumbprint *ok);
 /* readcert.c */
 uchar	*readcert(char *filename, int *pcertlen);
 PEMChain*readcertchain(char *filename);
+
+/* password-based key derivation function 2 (rfc2898) */
+void pbkdf2_x(uchar *p, ulong plen, uchar *s, ulong slen, ulong rounds, uchar *d, ulong dlen,
+	DigestState* (*x)(uchar*, ulong, uchar*, ulong, uchar*, DigestState*), int xlen);
+
+/* hmac-based key derivation function (rfc5869) */
+void hkdf_x(uchar *salt, ulong nsalt, uchar *info, ulong ninfo, uchar *key, ulong nkey, uchar *d, ulong dlen,
+	DigestState* (*x)(uchar*, ulong, uchar*, ulong, uchar*, DigestState*), int xlen);
+
+/* timing safe memcmp() */
+int tsmemcmp(void*, void*, ulong);
diff --git a/libsec/Makefile b/libsec/Makefile
index 7ba537d..53cd976 100644
--- a/libsec/Makefile
+++ b/libsec/Makefile
@@ -52,6 +52,11 @@ OFILES=\
 	sha2_128.$O\
 	sha2block128.$O\
 	smallprimes.$O\
+	pbkdf2.$O\
+	hkdf.$O\
+	poly1305.$O\
+	ccpoly.$O\
+	tsmemcmp.$O\
 
 default: $(LIB)
 $(LIB): $(OFILES)
diff --git a/libsec/ccpoly.c b/libsec/ccpoly.c
new file mode 100644
index 0000000..14a8a9c
--- /dev/null
+++ b/libsec/ccpoly.c
@@ -0,0 +1,84 @@
+#include <u.h>
+#include <libc.h>
+#include <libsec.h>
+
+static void
+ccpolyotk(Chachastate *cs, DigestState *ds)
+{
+	uchar otk[ChachaBsize];
+
+	memset(ds, 0, sizeof(*ds));
+	memset(otk, 0, 32);
+	chacha_setblock(cs, 0);
+	chacha_encrypt(otk, ChachaBsize, cs);
+	poly1305(nil, 0, otk, 32, nil, ds);
+}
+
+static void
+ccpolymac(uchar *buf, ulong nbuf, DigestState *ds)
+{
+	static uchar zeros[16] = {0};
+	ulong npad;
+
+	if(nbuf == 0)
+		return;
+	poly1305(buf, nbuf, nil, 0, nil, ds);
+	npad = nbuf % 16;
+	if(npad == 0)
+		return;
+	poly1305(zeros, 16 - npad, nil, 0, nil, ds);
+}
+
+static void
+ccpolytag(ulong ndat, ulong naad, uchar tag[16], DigestState *ds)
+{
+	uchar info[16];
+
+	info[0] = naad;
+	info[1] = naad>>8;
+	info[2] = naad>>16;
+	info[3] = naad>>24;
+	info[4] = 0;
+	info[5] = 0;
+	info[6] = 0;
+	info[7] = 0;
+
+	info[8]  = ndat;
+	info[9]  = ndat>>8;
+	info[10] = ndat>>16;
+	info[11] = ndat>>24;
+	info[12] = 0;
+	info[13] = 0;
+	info[14] = 0;
+	info[15] = 0;
+
+	poly1305(info, 16, nil, 0, tag, ds);
+}
+
+void
+ccpoly_encrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs)
+{
+	DigestState ds;
+
+	ccpolyotk(cs, &ds);
+	ccpolymac(aad, naad, &ds);
+	chacha_encrypt(dat, ndat, cs);
+	ccpolymac(dat, ndat, &ds);
+	ccpolytag(ndat, naad, tag, &ds);
+}
+
+int
+ccpoly_decrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs)
+{
+	DigestState ds;
+	uchar tmp[16];
+
+	ccpolyotk(cs, &ds);
+	ccpolymac(aad, naad, &ds);
+	ccpolymac(dat, ndat, &ds);
+	ccpolytag(ndat, naad, tmp, &ds);
+	if(tsmemcmp(tag, tmp, 16) != 0)
+		return -1;
+	chacha_encrypt(dat, ndat, cs);
+	return 0;
+}
diff --git a/libsec/chacha.c b/libsec/chacha.c
index 3f7b9f5..bcf9468 100644
--- a/libsec/chacha.c
+++ b/libsec/chacha.c
@@ -54,10 +54,12 @@ load(u32int *d, uchar *s, int nw)
 }
 
 void
-setupChachastate(Chachastate *s, uchar *key, usize keylen, uchar *iv, int rounds)
+setupChachastate(Chachastate *s, uchar *key, usize keylen, uchar *iv, ulong ivlen, int rounds)
 {
 	if(keylen != 256/8 && keylen != 128/8)
 		sysfatal("invalid chacha key length");
+	if(ivlen != 96/8 && ivlen != 64/8)
+		sysfatal("invalid chacha iv length");
 	if(rounds == 0)
 		rounds = 20;
 	s->rounds = rounds;
@@ -69,19 +71,28 @@ setupChachastate(Chachastate *s, uchar *key, usize keylen, uchar *iv, int rounds
 		load(&s->input[4], key, 4);
 		load(&s->input[8], key, 4);
 	}
+	s->ivwords = ivlen/sizeof(u32int);
 	s->input[12] = 0;
+	s->input[13] = 0;
 	if(iv == nil){
-		s->input[13] = 0;
 		s->input[14] = 0;
 		s->input[15] = 0;
 	}else
-		load(&s->input[13], iv, 3);
+		chacha_setiv(s, iv);
 }
 
 void
-chacha_setblock(Chachastate *s, u32int blockno)
+chacha_setiv(Chachastate *s, uchar *iv)
+{
+	load(&s->input[16 - s->ivwords], iv, s->ivwords);
+}
+
+void
+chacha_setblock(Chachastate *s, u64int blockno)
 {
 	s->input[12] = blockno;
+	if(s->ivwords == 2)
+		s->input[13] = blockno>>32;
 }
 
 static void
@@ -148,7 +159,8 @@ encryptblock(Chachastate *s, uchar *src, uchar *dst)
 	}
 #endif
 
-	s->input[12]++;
+	if(++s->input[12] == 0 && s->ivwords == 2)
+		s->input[13]++;
 }
 
 void
diff --git a/libsec/chachatest.c b/libsec/chachatest.c
index 7949c6f..c3d446b 100644
--- a/libsec/chachatest.c
+++ b/libsec/chachatest.c
@@ -31,7 +31,7 @@ u32int	rfccount = 1;
 char	rfctext[] = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, "
 	"sunscreen would be it.";
 uchar	rfcout[3*ChachaBsize];
-uchar	rfcref[3*ChachaBsize] = {
+uchar	rfcref[] = {
 	0x6e, 0x2e, 0x35, 0x9a, 0x25, 0x68, 0xf9, 0x80, 0x41, 0xba, 0x07, 0x28, 0xdd, 0x0d, 0x69, 0x81,
 	0xe9, 0x7e, 0x7a, 0xec, 0x1d, 0x43, 0x60, 0xc2, 0x0a, 0x27, 0xaf, 0xcc, 0xfd, 0x9f, 0xae, 0x0b,
 	0xf9, 0x1b, 0x65, 0xc5, 0x52, 0x47, 0x33, 0xab, 0x8f, 0x59, 0x3d, 0xab, 0xcd, 0x62, 0xb3, 0x57,
@@ -42,10 +42,26 @@ uchar	rfcref[3*ChachaBsize] = {
 	0x87, 0x4d
 };
 
+uchar	ccpaad[] = {
+	0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+};
+uchar	ccpkey[] = {
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+};
+uchar	ccpiv[] = {
+	0x07, 0x00, 0x00, 0x00,
+	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+};
+uchar	ccptag[] = {
+	0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60, 0x06, 0x91,
+};
+
 void
 main(int argc, char **argv)
 {
 	Chachastate s;
+	uchar tag[16];
 	int n;
 
 	ARGBEGIN{
@@ -54,17 +70,51 @@ main(int argc, char **argv)
 	print("key:\n");
 	printblock(rfckey, sizeof(rfckey));
 	n = strlen(rfctext);
-	setupChachastate(&s, rfckey, sizeof(rfckey), rfcnonce, 0);
+	setupChachastate(&s, rfckey, sizeof(rfckey), rfcnonce, sizeof(rfcnonce), 0);
 	chacha_setblock(&s, rfccount);
 	print("rfc in:\n");
 	printblock((uchar*)rfctext, n);
 	chacha_encrypt2((uchar*)rfctext, rfcout, n, &s);
 	print("rfc out:\n");
 	printblock(rfcout, n);
-	if(memcmp(rfcout, rfcref, sizeof(rfcout)) != 0){
+	if(memcmp(rfcout, rfcref, sizeof(rfcref)) != 0){
 		print("failure of vision\n");
 		exits("wrong");
 	}
+	print("\n");
+
+	print("ccpoly key:\n");
+	printblock(ccpkey, sizeof(ccpkey));
+
+	print("ccpoly iv:\n");
+	printblock(ccpiv, sizeof(ccpiv));
+
+	setupChachastate(&s, ccpkey, sizeof(ccpkey), ccpiv, sizeof(ccpiv), 20);
+
+	memmove(rfcout, rfctext, sizeof(rfctext)-1);
+	ccpoly_encrypt(rfcout, sizeof(rfctext)-1, ccpaad, sizeof(ccpaad), tag, &s);
+
+	print("ccpoly cipher:\n");
+	printblock(rfcout, sizeof(rfctext)-1);
+
+	print("ccpoly tag:\n");
+	printblock(tag, sizeof(tag));
+
+	if(memcmp(tag, ccptag, sizeof(tag)) != 0){
+		print("bad ccpoly tag\n");
+		exits("wrong");
+	}
+
+	if(ccpoly_decrypt(rfcout, sizeof(rfctext)-1, ccpaad, sizeof(ccpaad), tag, &s) != 0){
+		print("ccpoly decryption failed\n");
+		exits("wrong");
+	}
+
+	if(memcmp(rfcout, rfctext, sizeof(rfctext)-1) != 0){
+		print("ccpoly bad decryption\n");
+		exits("wrong");
+	}
+
 	print("passed\n");
 	exits(nil);
 }
diff --git a/libsec/hkdf.c b/libsec/hkdf.c
new file mode 100644
index 0000000..5e3f27b
--- /dev/null
+++ b/libsec/hkdf.c
@@ -0,0 +1,36 @@
+#include "os.h"
+#include <libsec.h>
+
+/* rfc5869 */
+void
+hkdf_x(uchar *salt, ulong nsalt, uchar *info, ulong ninfo,
+	uchar *key, ulong nkey, uchar *d, ulong dlen,
+	DigestState* (*x)(uchar*, ulong, uchar*, ulong, uchar*, DigestState*), int xlen)
+{
+	uchar prk[256], tmp[256], cnt;
+	DigestState *ds;
+
+	assert(xlen <= sizeof(tmp));
+
+	memset(tmp, 0, xlen);
+	if(nsalt == 0){
+		salt = tmp;
+		nsalt = xlen;
+	}
+	/* note that salt and key are swapped in this case */
+	(*x)(key, nkey, salt, nsalt, prk, nil);
+	ds = nil;
+	for(cnt=1;; cnt++) {
+		if(ninfo > 0)
+			ds = (*x)(info, ninfo, prk, xlen, nil, ds);
+		(*x)(&cnt, 1, prk, xlen, tmp, ds);
+		if(dlen <= xlen){
+			memmove(d, tmp, dlen);
+			break;
+		}
+		memmove(d, tmp, xlen);
+		dlen -= xlen;
+		d += xlen;
+		ds = (*x)(tmp, xlen, prk, xlen, nil, nil);
+	}
+}
diff --git a/libsec/pbkdf2.c b/libsec/pbkdf2.c
new file mode 100644
index 0000000..da3a646
--- /dev/null
+++ b/libsec/pbkdf2.c
@@ -0,0 +1,34 @@
+#include "os.h"
+#include <libsec.h>
+
+/* rfc2898 */
+void
+pbkdf2_x(p, plen, s, slen, rounds, d, dlen, x, xlen)
+	uchar *p, *s, *d;
+	ulong plen, slen, dlen, rounds;
+	DigestState* (*x)(uchar*, ulong, uchar*, ulong, uchar*, DigestState*);
+	int xlen;
+{
+	uchar block[256], tmp[256];
+	ulong i, j, k, n;
+	DigestState *ds;
+
+	assert(xlen <= sizeof(tmp));
+
+	for(i = 1; dlen > 0; i++, d += n, dlen -= n){
+		tmp[3] = i;
+		tmp[2] = i >> 8;
+		tmp[1] = i >> 16;
+		tmp[0] = i >> 24;
+		ds = (*x)(s, slen, p, plen, nil, nil);
+		(*x)(tmp, 4, p, plen, block, ds);
+		memmove(tmp, block, xlen);
+		for(j = 1; j < rounds; j++){
+			(*x)(tmp, xlen, p, plen, tmp, nil);
+			for(k=0; k<xlen; k++)
+				block[k] ^= tmp[k];
+		}
+		n = dlen > xlen ? xlen : dlen;
+		memmove(d, block, n); 
+	}
+}
diff --git a/libsec/poly1305.c b/libsec/poly1305.c
new file mode 100644
index 0000000..42f9ac4
--- /dev/null
+++ b/libsec/poly1305.c
@@ -0,0 +1,192 @@
+#include <u.h>
+#include <libc.h>
+#include <libsec.h>
+
+/*
+	poly1305 implementation using 32 bit * 32 bit = 64 bit multiplication and 64 bit addition
+
+	derived from http://github.com/floodberry/poly1305-donna
+*/
+
+#define U8TO32(p)	((u32int)(p)[0] | (u32int)(p)[1]<<8 | (u32int)(p)[2]<<16 | (u32int)(p)[3]<<24)
+#define U32TO8(p, v)	(p)[0]=(v), (p)[1]=(v)>>8, (p)[2]=(v)>>16, (p)[3]=(v)>>24
+
+/* (r,s) = (key[0:15],key[16:31]), the one time key */
+DigestState*
+poly1305(uchar *m, ulong len, uchar *key, ulong klen, uchar *digest, DigestState *s)
+{
+	u32int r0,r1,r2,r3,r4, s1,s2,s3,s4, h0,h1,h2,h3,h4, g0,g1,g2,g3,g4;
+	u64int d0,d1,d2,d3,d4, f;
+	u32int hibit, mask, c;
+
+	if(s == nil){
+		s = malloc(sizeof(*s));
+		if(s == nil)
+			return nil;
+		memset(s, 0, sizeof(*s));
+		s->malloced = 1;
+	}
+
+	if(s->seeded == 0){
+		assert(klen == 32);
+
+		/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+		s->state[0] = (U8TO32(&key[ 0])     ) & 0x3ffffff;
+		s->state[1] = (U8TO32(&key[ 3]) >> 2) & 0x3ffff03;
+		s->state[2] = (U8TO32(&key[ 6]) >> 4) & 0x3ffc0ff;
+		s->state[3] = (U8TO32(&key[ 9]) >> 6) & 0x3f03fff;
+		s->state[4] = (U8TO32(&key[12]) >> 8) & 0x00fffff;
+
+		/* h = 0 */
+		s->state[5] = 0;
+		s->state[6] = 0;
+		s->state[7] = 0;
+		s->state[8] = 0;
+		s->state[9] = 0;
+
+		/* save pad for later */
+		s->state[10] = U8TO32(&key[16]);
+		s->state[11] = U8TO32(&key[20]);
+		s->state[12] = U8TO32(&key[24]);
+		s->state[13] = U8TO32(&key[28]);
+
+		s->seeded = 1;
+	}
+
+	if(s->blen){
+		c = 16 - s->blen;
+		if(c > len)
+			c = len;
+		memmove(s->buf + s->blen, m, c);
+		len -= c, m += c;
+		s->blen += c;
+		if(s->blen == 16){
+			s->blen = 0;
+			poly1305(s->buf, 16, key, klen, nil, s);
+		}
+	}
+
+	r0 = s->state[0];
+	r1 = s->state[1];
+	r2 = s->state[2];
+	r3 = s->state[3];
+	r4 = s->state[4];
+
+	h0 = s->state[5];
+	h1 = s->state[6];
+	h2 = s->state[7];
+	h3 = s->state[8];
+	h4 = s->state[9];
+
+	s1 = r1 * 5;
+	s2 = r2 * 5;
+	s3 = r3 * 5;
+	s4 = r4 * 5;
+
+	hibit = 1<<24;	/* 1<<128 */
+
+	while(len >= 16){
+Block:
+		/* h += m[i] */
+		h0 += (U8TO32(&m[0])     ) & 0x3ffffff;
+		h1 += (U8TO32(&m[3]) >> 2) & 0x3ffffff;
+		h2 += (U8TO32(&m[6]) >> 4) & 0x3ffffff;
+		h3 += (U8TO32(&m[9]) >> 6) & 0x3ffffff;
+		h4 += (U8TO32(&m[12])>> 8) | hibit;
+
+		/* h *= r */
+		d0 = ((u64int)h0 * r0) + ((u64int)h1 * s4) + ((u64int)h2 * s3) + ((u64int)h3 * s2) + ((u64int)h4 * s1);
+		d1 = ((u64int)h0 * r1) + ((u64int)h1 * r0) + ((u64int)h2 * s4) + ((u64int)h3 * s3) + ((u64int)h4 * s2);
+		d2 = ((u64int)h0 * r2) + ((u64int)h1 * r1) + ((u64int)h2 * r0) + ((u64int)h3 * s4) + ((u64int)h4 * s3);
+		d3 = ((u64int)h0 * r3) + ((u64int)h1 * r2) + ((u64int)h2 * r1) + ((u64int)h3 * r0) + ((u64int)h4 * s4);
+		d4 = ((u64int)h0 * r4) + ((u64int)h1 * r3) + ((u64int)h2 * r2) + ((u64int)h3 * r1) + ((u64int)h4 * r0);
+
+		/* (partial) h %= p */
+		              c = (u32int)(d0 >> 26); h0 = (u32int)d0 & 0x3ffffff;
+		d1 += c;      c = (u32int)(d1 >> 26); h1 = (u32int)d1 & 0x3ffffff;
+		d2 += c;      c = (u32int)(d2 >> 26); h2 = (u32int)d2 & 0x3ffffff;
+		d3 += c;      c = (u32int)(d3 >> 26); h3 = (u32int)d3 & 0x3ffffff;
+		d4 += c;      c = (u32int)(d4 >> 26); h4 = (u32int)d4 & 0x3ffffff;
+		h0 += c * 5;  c = (h0 >> 26); h0 = h0 & 0x3ffffff;
+		h1 += c;
+
+		len -= 16, m += 16;
+	}
+
+	if(len){
+		s->blen = len;
+		memmove(s->buf, m, len);
+	}
+
+	if(digest == nil){
+		s->state[5] = h0;
+		s->state[6] = h1;
+		s->state[7] = h2;
+		s->state[8] = h3;
+		s->state[9] = h4;
+		return s;
+	}
+
+	if(len){
+		m = s->buf;
+		m[len++] = 1;
+		while(len < 16)
+			m[len++] = 0;
+		hibit = 0;
+		goto Block;
+	}
+
+	             c = h1 >> 26; h1 = h1 & 0x3ffffff;
+	h2 +=     c; c = h2 >> 26; h2 = h2 & 0x3ffffff;
+	h3 +=     c; c = h3 >> 26; h3 = h3 & 0x3ffffff;
+	h4 +=     c; c = h4 >> 26; h4 = h4 & 0x3ffffff;
+	h0 += c * 5; c = h0 >> 26; h0 = h0 & 0x3ffffff;
+	h1 +=     c;
+
+	/* compute h + -p */
+	g0 = h0 + 5; c = g0 >> 26; g0 &= 0x3ffffff;
+	g1 = h1 + c; c = g1 >> 26; g1 &= 0x3ffffff;
+	g2 = h2 + c; c = g2 >> 26; g2 &= 0x3ffffff;
+	g3 = h3 + c; c = g3 >> 26; g3 &= 0x3ffffff;
+	g4 = h4 + c - (1 << 26);
+
+	/* select h if h < p, or h + -p if h >= p */
+	mask = (g4 >> 31) - 1;
+	g0 &= mask;
+	g1 &= mask;
+	g2 &= mask;
+	g3 &= mask;
+	g4 &= mask;
+	mask = ~mask;
+	h0 = (h0 & mask) | g0;
+	h1 = (h1 & mask) | g1;
+	h2 = (h2 & mask) | g2;
+	h3 = (h3 & mask) | g3;
+	h4 = (h4 & mask) | g4;
+
+	/* h = h % (2^128) */
+	h0 = (h0      ) | (h1 << 26);
+	h1 = (h1 >>  6) | (h2 << 20);
+	h2 = (h2 >> 12) | (h3 << 14);
+	h3 = (h3 >> 18) | (h4 <<  8);
+
+	/* digest = (h + pad) % (2^128) */
+	f = (u64int)h0 + s->state[10]            ; h0 = (u32int)f;
+	f = (u64int)h1 + s->state[11] + (f >> 32); h1 = (u32int)f;
+	f = (u64int)h2 + s->state[12] + (f >> 32); h2 = (u32int)f;
+	f = (u64int)h3 + s->state[13] + (f >> 32); h3 = (u32int)f;
+
+	U32TO8(&digest[0], h0);
+	U32TO8(&digest[4], h1);
+	U32TO8(&digest[8], h2);
+	U32TO8(&digest[12], h3);
+
+	if(s->malloced){
+		memset(s, 0, sizeof(*s));
+		free(s);
+		return nil;
+	}
+
+	memset(s, 0, sizeof(*s));
+	return nil;
+}
diff --git a/libsec/tsmemcmp.c b/libsec/tsmemcmp.c
new file mode 100644
index 0000000..6cc7537
--- /dev/null
+++ b/libsec/tsmemcmp.c
@@ -0,0 +1,26 @@
+#include <u.h>
+#include <libc.h>
+#include <libsec.h>
+
+/*
+ * timing safe memcmp()
+ */
+int
+tsmemcmp(void *a1, void *a2, ulong n)
+{
+	int lt, gt, c1, c2, r, m;
+	uchar *s1, *s2;
+
+	r = m = 0;
+	s1 = a1;
+	s2 = a2;
+	while(n--){
+		c1 = *s1++;
+		c2 = *s2++;
+		lt = (c1 - c2) >> 8;
+		gt = (c2 - c1) >> 8;
+		r |= (lt - gt) & ~m;
+		m |= lt | gt;
+	}
+	return r;
+}