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-rw-r--r--libtomcrypt/src/mac/poly1305/poly1305.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/libtomcrypt/src/mac/poly1305/poly1305.c b/libtomcrypt/src/mac/poly1305/poly1305.c
new file mode 100644
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+++ b/libtomcrypt/src/mac/poly1305/poly1305.c
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+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+
+/* The implementation is based on:
+ * Public Domain poly1305 from Andrew Moon
+ * https://github.com/floodyberry/poly1305-donna
+ */
+
+#include "tomcrypt.h"
+
+#ifdef LTC_POLY1305
+
+/* internal only */
+static void _poly1305_block(poly1305_state *st, const unsigned char *in, unsigned long inlen)
+{
+ const unsigned long hibit = (st->final) ? 0 : (1UL << 24); /* 1 << 128 */
+ ulong32 r0,r1,r2,r3,r4;
+ ulong32 s1,s2,s3,s4;
+ ulong32 h0,h1,h2,h3,h4;
+ ulong32 tmp;
+ ulong64 d0,d1,d2,d3,d4;
+ ulong32 c;
+
+ r0 = st->r[0];
+ r1 = st->r[1];
+ r2 = st->r[2];
+ r3 = st->r[3];
+ r4 = st->r[4];
+
+ s1 = r1 * 5;
+ s2 = r2 * 5;
+ s3 = r3 * 5;
+ s4 = r4 * 5;
+
+ h0 = st->h[0];
+ h1 = st->h[1];
+ h2 = st->h[2];
+ h3 = st->h[3];
+ h4 = st->h[4];
+
+ while (inlen >= 16) {
+ /* h += in[i] */
+ LOAD32L(tmp, in+ 0); h0 += (tmp ) & 0x3ffffff;
+ LOAD32L(tmp, in+ 3); h1 += (tmp >> 2) & 0x3ffffff;
+ LOAD32L(tmp, in+ 6); h2 += (tmp >> 4) & 0x3ffffff;
+ LOAD32L(tmp, in+ 9); h3 += (tmp >> 6) & 0x3ffffff;
+ LOAD32L(tmp, in+12); h4 += (tmp >> 8) | hibit;
+
+ /* h *= r */
+ d0 = ((ulong64)h0 * r0) + ((ulong64)h1 * s4) + ((ulong64)h2 * s3) + ((ulong64)h3 * s2) + ((ulong64)h4 * s1);
+ d1 = ((ulong64)h0 * r1) + ((ulong64)h1 * r0) + ((ulong64)h2 * s4) + ((ulong64)h3 * s3) + ((ulong64)h4 * s2);
+ d2 = ((ulong64)h0 * r2) + ((ulong64)h1 * r1) + ((ulong64)h2 * r0) + ((ulong64)h3 * s4) + ((ulong64)h4 * s3);
+ d3 = ((ulong64)h0 * r3) + ((ulong64)h1 * r2) + ((ulong64)h2 * r1) + ((ulong64)h3 * r0) + ((ulong64)h4 * s4);
+ d4 = ((ulong64)h0 * r4) + ((ulong64)h1 * r3) + ((ulong64)h2 * r2) + ((ulong64)h3 * r1) + ((ulong64)h4 * r0);
+
+ /* (partial) h %= p */
+ c = (ulong32)(d0 >> 26); h0 = (ulong32)d0 & 0x3ffffff;
+ d1 += c; c = (ulong32)(d1 >> 26); h1 = (ulong32)d1 & 0x3ffffff;
+ d2 += c; c = (ulong32)(d2 >> 26); h2 = (ulong32)d2 & 0x3ffffff;
+ d3 += c; c = (ulong32)(d3 >> 26); h3 = (ulong32)d3 & 0x3ffffff;
+ d4 += c; c = (ulong32)(d4 >> 26); h4 = (ulong32)d4 & 0x3ffffff;
+ h0 += c * 5; c = (h0 >> 26); h0 = h0 & 0x3ffffff;
+ h1 += c;
+
+ in += 16;
+ inlen -= 16;
+ }
+
+ st->h[0] = h0;
+ st->h[1] = h1;
+ st->h[2] = h2;
+ st->h[3] = h3;
+ st->h[4] = h4;
+}
+
+/**
+ Initialize an POLY1305 context.
+ @param st The POLY1305 state
+ @param key The secret key
+ @param keylen The length of the secret key (octets)
+ @return CRYPT_OK if successful
+*/
+int poly1305_init(poly1305_state *st, const unsigned char *key, unsigned long keylen)
+{
+ LTC_ARGCHK(st != NULL);
+ LTC_ARGCHK(key != NULL);
+ LTC_ARGCHK(keylen == 32);
+
+ /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+ LOAD32L(st->r[0], key + 0); st->r[0] = (st->r[0] ) & 0x3ffffff;
+ LOAD32L(st->r[1], key + 3); st->r[1] = (st->r[1] >> 2) & 0x3ffff03;
+ LOAD32L(st->r[2], key + 6); st->r[2] = (st->r[2] >> 4) & 0x3ffc0ff;
+ LOAD32L(st->r[3], key + 9); st->r[3] = (st->r[3] >> 6) & 0x3f03fff;
+ LOAD32L(st->r[4], key + 12); st->r[4] = (st->r[4] >> 8) & 0x00fffff;
+
+ /* h = 0 */
+ st->h[0] = 0;
+ st->h[1] = 0;
+ st->h[2] = 0;
+ st->h[3] = 0;
+ st->h[4] = 0;
+
+ /* save pad for later */
+ LOAD32L(st->pad[0], key + 16);
+ LOAD32L(st->pad[1], key + 20);
+ LOAD32L(st->pad[2], key + 24);
+ LOAD32L(st->pad[3], key + 28);
+
+ st->leftover = 0;
+ st->final = 0;
+ return CRYPT_OK;
+}
+
+/**
+ Process data through POLY1305
+ @param st The POLY1305 state
+ @param in The data to send through HMAC
+ @param inlen The length of the data to HMAC (octets)
+ @return CRYPT_OK if successful
+*/
+int poly1305_process(poly1305_state *st, const unsigned char *in, unsigned long inlen)
+{
+ unsigned long i;
+
+ if (inlen == 0) return CRYPT_OK; /* nothing to do */
+ LTC_ARGCHK(st != NULL);
+ LTC_ARGCHK(in != NULL);
+
+ /* handle leftover */
+ if (st->leftover) {
+ unsigned long want = (16 - st->leftover);
+ if (want > inlen) want = inlen;
+ for (i = 0; i < want; i++) st->buffer[st->leftover + i] = in[i];
+ inlen -= want;
+ in += want;
+ st->leftover += want;
+ if (st->leftover < 16) return CRYPT_OK;
+ _poly1305_block(st, st->buffer, 16);
+ st->leftover = 0;
+ }
+
+ /* process full blocks */
+ if (inlen >= 16) {
+ unsigned long want = (inlen & ~(16 - 1));
+ _poly1305_block(st, in, want);
+ in += want;
+ inlen -= want;
+ }
+
+ /* store leftover */
+ if (inlen) {
+ for (i = 0; i < inlen; i++) st->buffer[st->leftover + i] = in[i];
+ st->leftover += inlen;
+ }
+ return CRYPT_OK;
+}
+
+/**
+ Terminate a POLY1305 session
+ @param st The POLY1305 state
+ @param mac [out] The destination of the POLY1305 authentication tag
+ @param maclen [in/out] The max size and resulting size of the POLY1305 authentication tag
+ @return CRYPT_OK if successful
+*/
+int poly1305_done(poly1305_state *st, unsigned char *mac, unsigned long *maclen)
+{
+ ulong32 h0,h1,h2,h3,h4,c;
+ ulong32 g0,g1,g2,g3,g4;
+ ulong64 f;
+ ulong32 mask;
+
+ LTC_ARGCHK(st != NULL);
+ LTC_ARGCHK(mac != NULL);
+ LTC_ARGCHK(maclen != NULL);
+ LTC_ARGCHK(*maclen >= 16);
+
+ /* process the remaining block */
+ if (st->leftover) {
+ unsigned long i = st->leftover;
+ st->buffer[i++] = 1;
+ for (; i < 16; i++) st->buffer[i] = 0;
+ st->final = 1;
+ _poly1305_block(st, st->buffer, 16);
+ }
+
+ /* fully carry h */
+ h0 = st->h[0];
+ h1 = st->h[1];
+ h2 = st->h[2];
+ h3 = st->h[3];
+ h4 = st->h[4];
+
+ 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 - (1UL << 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)) & 0xffffffff;
+ h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;
+ h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
+ h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;
+
+ /* mac = (h + pad) % (2^128) */
+ f = (ulong64)h0 + st->pad[0] ; h0 = (ulong32)f;
+ f = (ulong64)h1 + st->pad[1] + (f >> 32); h1 = (ulong32)f;
+ f = (ulong64)h2 + st->pad[2] + (f >> 32); h2 = (ulong32)f;
+ f = (ulong64)h3 + st->pad[3] + (f >> 32); h3 = (ulong32)f;
+
+ STORE32L(h0, mac + 0);
+ STORE32L(h1, mac + 4);
+ STORE32L(h2, mac + 8);
+ STORE32L(h3, mac + 12);
+
+ /* zero out the state */
+ st->h[0] = 0;
+ st->h[1] = 0;
+ st->h[2] = 0;
+ st->h[3] = 0;
+ st->h[4] = 0;
+ st->r[0] = 0;
+ st->r[1] = 0;
+ st->r[2] = 0;
+ st->r[3] = 0;
+ st->r[4] = 0;
+ st->pad[0] = 0;
+ st->pad[1] = 0;
+ st->pad[2] = 0;
+ st->pad[3] = 0;
+
+ *maclen = 16;
+ return CRYPT_OK;
+}
+
+#endif
+
+/* ref: $Format:%D$ */
+/* git commit: $Format:%H$ */
+/* commit time: $Format:%ai$ */
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