mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-19 13:07:55 +00:00
126 lines
2.8 KiB
C++
126 lines
2.8 KiB
C++
/*
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20080912
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D. J. Bernstein
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Public domain.
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*/
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#include "Constants.hpp"
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#include "Poly1305.hpp"
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#ifdef __WINDOWS__
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#pragma warning(disable: 4146)
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#endif
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namespace ZeroTier {
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//////////////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////////////
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static void add(unsigned int h[17],const unsigned int c[17])
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{
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j < 17;++j) { u += h[j] + c[j]; h[j] = u & 255; u >>= 8; }
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}
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static void squeeze(unsigned int h[17])
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{
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j < 16;++j) { u += h[j]; h[j] = u & 255; u >>= 8; }
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u += h[16]; h[16] = u & 3;
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u = 5 * (u >> 2);
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for (j = 0;j < 16;++j) { u += h[j]; h[j] = u & 255; u >>= 8; }
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u += h[16]; h[16] = u;
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}
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static const unsigned int minusp[17] = {
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5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 252
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} ;
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static void freeze(unsigned int h[17])
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{
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unsigned int horig[17];
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unsigned int j;
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unsigned int negative;
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for (j = 0;j < 17;++j) horig[j] = h[j];
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add(h,minusp);
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negative = -(h[16] >> 7);
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for (j = 0;j < 17;++j) h[j] ^= negative & (horig[j] ^ h[j]);
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}
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static void mulmod(unsigned int h[17],const unsigned int r[17])
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{
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unsigned int hr[17];
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unsigned int i;
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unsigned int j;
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unsigned int u;
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for (i = 0;i < 17;++i) {
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u = 0;
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for (j = 0;j <= i;++j) u += h[j] * r[i - j];
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for (j = i + 1;j < 17;++j) u += 320 * h[j] * r[i + 17 - j];
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hr[i] = u;
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}
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for (i = 0;i < 17;++i) h[i] = hr[i];
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squeeze(h);
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}
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static inline int crypto_onetimeauth(unsigned char *out,const unsigned char *in,unsigned long long inlen,const unsigned char *k)
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{
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unsigned int j;
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unsigned int r[17];
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unsigned int h[17];
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unsigned int c[17];
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r[0] = k[0];
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r[1] = k[1];
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r[2] = k[2];
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r[3] = k[3] & 15;
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r[4] = k[4] & 252;
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r[5] = k[5];
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r[6] = k[6];
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r[7] = k[7] & 15;
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r[8] = k[8] & 252;
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r[9] = k[9];
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r[10] = k[10];
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r[11] = k[11] & 15;
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r[12] = k[12] & 252;
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r[13] = k[13];
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r[14] = k[14];
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r[15] = k[15] & 15;
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r[16] = 0;
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for (j = 0;j < 17;++j) h[j] = 0;
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while (inlen > 0) {
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for (j = 0;j < 17;++j) c[j] = 0;
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for (j = 0;(j < 16) && (j < inlen);++j) c[j] = in[j];
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c[j] = 1;
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in += j; inlen -= j;
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add(h,c);
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mulmod(h,r);
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}
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freeze(h);
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for (j = 0;j < 16;++j) c[j] = k[j + 16];
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c[16] = 0;
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add(h,c);
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for (j = 0;j < 16;++j) out[j] = h[j];
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return 0;
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}
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//////////////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////////////
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void Poly1305::compute(void *auth,const void *data,unsigned int len,const void *key)
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throw()
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{
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crypto_onetimeauth((unsigned char *)auth,(const unsigned char *)data,len,(const unsigned char *)key);
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}
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} // namespace ZeroTier
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