- djm@cvs.openbsd.org 2013/11/21 00:45:44

     [Makefile.in PROTOCOL PROTOCOL.chacha20poly1305 authfile.c chacha.c]
     [chacha.h cipher-chachapoly.c cipher-chachapoly.h cipher.c cipher.h]
     [dh.c myproposal.h packet.c poly1305.c poly1305.h servconf.c ssh.1]
     [ssh.c ssh_config.5 sshd_config.5] Add a new protocol 2 transport
     cipher "chacha20-poly1305@openssh.com" that combines Daniel
     Bernstein's ChaCha20 stream cipher and Poly1305 MAC to build an
     authenticated encryption mode.

     Inspired by and similar to Adam Langley's proposal for TLS:
     http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-03
     but differs in layout used for the MAC calculation and the use of a
     second ChaCha20 instance to separately encrypt packet lengths.
     Details are in the PROTOCOL.chacha20poly1305 file.

     Feedback markus@, naddy@; manpage bits Loganden Velvindron @ AfriNIC
     ok markus@ naddy@

1 files changed, 158 insertions, 0 deletions

diff --git a/poly1305.c b/poly1305.c
new file mode 100644
index 000000000..059cc60f7
--- /dev/null
+++ b/poly1305.c
@@ -0,0 +1,158 @@
+/* 
+ * Public Domain poly1305 from Andrew M.
+ * poly1305-donna-unrolled.c from https://github.com/floodyberry/poly1305-donna
+ */
+
+/* $OpenBSD: poly1305.c,v 1.2 2013/11/21 02:50:00 djm Exp $ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <stdint.h>
+
+#include "poly1305.h"
+
+#define mul32x32_64(a,b) ((uint64_t)(a) * (b))
+
+#define U8TO32_LE(p) \
+        (((uint32_t)((p)[0])) | \
+         ((uint32_t)((p)[1]) <<  8) | \
+         ((uint32_t)((p)[2]) << 16) | \
+         ((uint32_t)((p)[3]) << 24))
+
+#define U32TO8_LE(p, v) \
+        do { \
+                (p)[0] = (uint8_t)((v)); \
+                (p)[1] = (uint8_t)((v) >>  8); \
+                (p)[2] = (uint8_t)((v) >> 16); \
+                (p)[3] = (uint8_t)((v) >> 24); \
+        } while (0)
+
+void
+poly1305_auth(unsigned char out[POLY1305_TAGLEN], const unsigned char *m, size_t inlen, const unsigned char key[POLY1305_KEYLEN]) {
+        uint32_t t0,t1,t2,t3;
+        uint32_t h0,h1,h2,h3,h4;
+        uint32_t r0,r1,r2,r3,r4;
+        uint32_t s1,s2,s3,s4;
+        uint32_t b, nb;
+        size_t j;
+        uint64_t t[5];
+        uint64_t f0,f1,f2,f3;
+        uint32_t g0,g1,g2,g3,g4;
+        uint64_t c;
+        unsigned char mp[16];
+
+        /* clamp key */
+        t0 = U8TO32_LE(key+0);
+        t1 = U8TO32_LE(key+4);
+        t2 = U8TO32_LE(key+8);
+        t3 = U8TO32_LE(key+12);
+
+        /* precompute multipliers */
+        r0 = t0 & 0x3ffffff; t0 >>= 26; t0 |= t1 << 6;
+        r1 = t0 & 0x3ffff03; t1 >>= 20; t1 |= t2 << 12;
+        r2 = t1 & 0x3ffc0ff; t2 >>= 14; t2 |= t3 << 18;
+        r3 = t2 & 0x3f03fff; t3 >>= 8;
+        r4 = t3 & 0x00fffff;
+
+        s1 = r1 * 5;
+        s2 = r2 * 5;
+        s3 = r3 * 5;
+        s4 = r4 * 5;
+
+        /* init state */
+        h0 = 0;
+        h1 = 0;
+        h2 = 0;
+        h3 = 0;
+        h4 = 0;
+
+        /* full blocks */
+        if (inlen < 16) goto poly1305_donna_atmost15bytes;
+poly1305_donna_16bytes:
+        m += 16;
+        inlen -= 16;
+
+        t0 = U8TO32_LE(m-16);
+        t1 = U8TO32_LE(m-12);
+        t2 = U8TO32_LE(m-8);
+        t3 = U8TO32_LE(m-4);
+
+        h0 += t0 & 0x3ffffff;
+        h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
+        h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
+        h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
+        h4 += (t3 >> 8) | (1 << 24);
+
+
+poly1305_donna_mul:
+        t[0]  = mul32x32_64(h0,r0) + mul32x32_64(h1,s4) + mul32x32_64(h2,s3) + mul32x32_64(h3,s2) + mul32x32_64(h4,s1);
+        t[1]  = mul32x32_64(h0,r1) + mul32x32_64(h1,r0) + mul32x32_64(h2,s4) + mul32x32_64(h3,s3) + mul32x32_64(h4,s2);
+        t[2]  = mul32x32_64(h0,r2) + mul32x32_64(h1,r1) + mul32x32_64(h2,r0) + mul32x32_64(h3,s4) + mul32x32_64(h4,s3);
+        t[3]  = mul32x32_64(h0,r3) + mul32x32_64(h1,r2) + mul32x32_64(h2,r1) + mul32x32_64(h3,r0) + mul32x32_64(h4,s4);
+        t[4]  = mul32x32_64(h0,r4) + mul32x32_64(h1,r3) + mul32x32_64(h2,r2) + mul32x32_64(h3,r1) + mul32x32_64(h4,r0);
+
+                        h0 = (uint32_t)t[0] & 0x3ffffff; c =           (t[0] >> 26);
+        t[1] += c;      h1 = (uint32_t)t[1] & 0x3ffffff; b = (uint32_t)(t[1] >> 26);
+        t[2] += b;      h2 = (uint32_t)t[2] & 0x3ffffff; b = (uint32_t)(t[2] >> 26);
+        t[3] += b;      h3 = (uint32_t)t[3] & 0x3ffffff; b = (uint32_t)(t[3] >> 26);
+        t[4] += b;      h4 = (uint32_t)t[4] & 0x3ffffff; b = (uint32_t)(t[4] >> 26);
+        h0 += b * 5;
+
+        if (inlen >= 16) goto poly1305_donna_16bytes;
+
+        /* final bytes */
+poly1305_donna_atmost15bytes:
+        if (!inlen) goto poly1305_donna_finish;
+
+        for (j = 0; j < inlen; j++) mp[j] = m[j];
+        mp[j++] = 1;
+        for (; j < 16; j++)     mp[j] = 0;
+        inlen = 0;
+
+        t0 = U8TO32_LE(mp+0);
+        t1 = U8TO32_LE(mp+4);
+        t2 = U8TO32_LE(mp+8);
+        t3 = U8TO32_LE(mp+12);
+
+        h0 += t0 & 0x3ffffff;
+        h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
+        h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
+        h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
+        h4 += (t3 >> 8);
+
+        goto poly1305_donna_mul;
+
+poly1305_donna_finish:
+                     b = h0 >> 26; h0 = h0 & 0x3ffffff;
+        h1 +=     b; b = h1 >> 26; h1 = h1 & 0x3ffffff;
+        h2 +=     b; b = h2 >> 26; h2 = h2 & 0x3ffffff;
+        h3 +=     b; b = h3 >> 26; h3 = h3 & 0x3ffffff;
+        h4 +=     b; b = h4 >> 26; h4 = h4 & 0x3ffffff;
+        h0 += b * 5; b = h0 >> 26; h0 = h0 & 0x3ffffff;
+        h1 +=     b;
+
+        g0 = h0 + 5; b = g0 >> 26; g0 &= 0x3ffffff;
+        g1 = h1 + b; b = g1 >> 26; g1 &= 0x3ffffff;
+        g2 = h2 + b; b = g2 >> 26; g2 &= 0x3ffffff;
+        g3 = h3 + b; b = g3 >> 26; g3 &= 0x3ffffff;
+        g4 = h4 + b - (1 << 26);
+
+        b = (g4 >> 31) - 1;
+        nb = ~b;
+        h0 = (h0 & nb) | (g0 & b);
+        h1 = (h1 & nb) | (g1 & b);
+        h2 = (h2 & nb) | (g2 & b);
+        h3 = (h3 & nb) | (g3 & b);
+        h4 = (h4 & nb) | (g4 & b);
+
+        f0 = ((h0      ) | (h1 << 26)) + (uint64_t)U8TO32_LE(&key[16]);
+        f1 = ((h1 >>  6) | (h2 << 20)) + (uint64_t)U8TO32_LE(&key[20]);
+        f2 = ((h2 >> 12) | (h3 << 14)) + (uint64_t)U8TO32_LE(&key[24]);
+        f3 = ((h3 >> 18) | (h4 <<  8)) + (uint64_t)U8TO32_LE(&key[28]);
+
+        U32TO8_LE(&out[ 0], f0); f1 += (f0 >> 32);
+        U32TO8_LE(&out[ 4], f1); f2 += (f1 >> 32);
+        U32TO8_LE(&out[ 8], f2); f3 += (f2 >> 32);
+        U32TO8_LE(&out[12], f3);
+}