1 files changed, 359 insertions, 0 deletions
diff --git a/src/lib/pubkey/ed25519/sc_reduce.cpp b/src/lib/pubkey/ed25519/sc_reduce.cpp
new file mode 100644
index 000000000..93dcc6de8
--- /dev/null
+++ b/src/lib/pubkey/ed25519/sc_reduce.cpp
@@ -0,0 +1,359 @@
+/*
+* Ed25519
+* (C) 2017 Ribose Inc
+*
+* Based on the public domain code from SUPERCOP ref10 by
+* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/ed25519_internal.h>
+
+namespace Botan {
+
+/*
+Input:
+  s[0]+256*s[1]+...+256^63*s[63] = s
+
+Output:
+  s[0]+256*s[1]+...+256^31*s[31] = s mod l
+  where l = 2^252 + 27742317777372353535851937790883648493.
+  Overwrites s in place.
+*/
+
+void sc_reduce(uint8_t* s)
+   {
+   int64_t s0 = 2097151 & load_3(s);
+   int64_t s1 = 2097151 & (load_4(s + 2) >> 5);
+   int64_t s2 = 2097151 & (load_3(s + 5) >> 2);
+   int64_t s3 = 2097151 & (load_4(s + 7) >> 7);
+   int64_t s4 = 2097151 & (load_4(s + 10) >> 4);
+   int64_t s5 = 2097151 & (load_3(s + 13) >> 1);
+   int64_t s6 = 2097151 & (load_4(s + 15) >> 6);
+   int64_t s7 = 2097151 & (load_3(s + 18) >> 3);
+   int64_t s8 = 2097151 & load_3(s + 21);
+   int64_t s9 = 2097151 & (load_4(s + 23) >> 5);
+   int64_t s10 = 2097151 & (load_3(s + 26) >> 2);
+   int64_t s11 = 2097151 & (load_4(s + 28) >> 7);
+   int64_t s12 = 2097151 & (load_4(s + 31) >> 4);
+   int64_t s13 = 2097151 & (load_3(s + 34) >> 1);
+   int64_t s14 = 2097151 & (load_4(s + 36) >> 6);
+   int64_t s15 = 2097151 & (load_3(s + 39) >> 3);
+   int64_t s16 = 2097151 & load_3(s + 42);
+   int64_t s17 = 2097151 & (load_4(s + 44) >> 5);
+   int64_t s18 = 2097151 & (load_3(s + 47) >> 2);
+   int64_t s19 = 2097151 & (load_4(s + 49) >> 7);
+   int64_t s20 = 2097151 & (load_4(s + 52) >> 4);
+   int64_t s21 = 2097151 & (load_3(s + 55) >> 1);
+   int64_t s22 = 2097151 & (load_4(s + 57) >> 6);
+   int64_t s23 = (load_4(s + 60) >> 3);
+   int64_t carry0;
+   int64_t carry1;
+   int64_t carry2;
+   int64_t carry3;
+   int64_t carry4;
+   int64_t carry5;
+   int64_t carry6;
+   int64_t carry7;
+   int64_t carry8;
+   int64_t carry9;
+   int64_t carry10;
+   int64_t carry11;
+   int64_t carry12;
+   int64_t carry13;
+   int64_t carry14;
+   int64_t carry15;
+   int64_t carry16;
+
+   s11 += s23 * 666643;
+   s12 += s23 * 470296;
+   s13 += s23 * 654183;
+   s14 -= s23 * 997805;
+   s15 += s23 * 136657;
+   s16 -= s23 * 683901;
+   s23 = 0;
+
+   s10 += s22 * 666643;
+   s11 += s22 * 470296;
+   s12 += s22 * 654183;
+   s13 -= s22 * 997805;
+   s14 += s22 * 136657;
+   s15 -= s22 * 683901;
+   s22 = 0;
+
+   s9 += s21 * 666643;
+   s10 += s21 * 470296;
+   s11 += s21 * 654183;
+   s12 -= s21 * 997805;
+   s13 += s21 * 136657;
+   s14 -= s21 * 683901;
+   s21 = 0;
+
+   s8 += s20 * 666643;
+   s9 += s20 * 470296;
+   s10 += s20 * 654183;
+   s11 -= s20 * 997805;
+   s12 += s20 * 136657;
+   s13 -= s20 * 683901;
+   s20 = 0;
+
+   s7 += s19 * 666643;
+   s8 += s19 * 470296;
+   s9 += s19 * 654183;
+   s10 -= s19 * 997805;
+   s11 += s19 * 136657;
+   s12 -= s19 * 683901;
+   s19 = 0;
+
+   s6 += s18 * 666643;
+   s7 += s18 * 470296;
+   s8 += s18 * 654183;
+   s9 -= s18 * 997805;
+   s10 += s18 * 136657;
+   s11 -= s18 * 683901;
+   s18 = 0;
+
+   carry6 = (s6 + (1<<20)) >> 21;
+   s7 += carry6;
+   s6 -= carry6 << 21;
+   carry8 = (s8 + (1<<20)) >> 21;
+   s9 += carry8;
+   s8 -= carry8 << 21;
+   carry10 = (s10 + (1<<20)) >> 21;
+   s11 += carry10;
+   s10 -= carry10 << 21;
+   carry12 = (s12 + (1<<20)) >> 21;
+   s13 += carry12;
+   s12 -= carry12 << 21;
+   carry14 = (s14 + (1<<20)) >> 21;
+   s15 += carry14;
+   s14 -= carry14 << 21;
+   carry16 = (s16 + (1<<20)) >> 21;
+   s17 += carry16;
+   s16 -= carry16 << 21;
+
+   carry7 = (s7 + (1<<20)) >> 21;
+   s8 += carry7;
+   s7 -= carry7 << 21;
+   carry9 = (s9 + (1<<20)) >> 21;
+   s10 += carry9;
+   s9 -= carry9 << 21;
+   carry11 = (s11 + (1<<20)) >> 21;
+   s12 += carry11;
+   s11 -= carry11 << 21;
+   carry13 = (s13 + (1<<20)) >> 21;
+   s14 += carry13;
+   s13 -= carry13 << 21;
+   carry15 = (s15 + (1<<20)) >> 21;
+   s16 += carry15;
+   s15 -= carry15 << 21;
+
+   s5 += s17 * 666643;
+   s6 += s17 * 470296;
+   s7 += s17 * 654183;
+   s8 -= s17 * 997805;
+   s9 += s17 * 136657;
+   s10 -= s17 * 683901;
+   s17 = 0;
+
+   s4 += s16 * 666643;
+   s5 += s16 * 470296;
+   s6 += s16 * 654183;
+   s7 -= s16 * 997805;
+   s8 += s16 * 136657;
+   s9 -= s16 * 683901;
+   s16 = 0;
+
+   s3 += s15 * 666643;
+   s4 += s15 * 470296;
+   s5 += s15 * 654183;
+   s6 -= s15 * 997805;
+   s7 += s15 * 136657;
+   s8 -= s15 * 683901;
+   s15 = 0;
+
+   s2 += s14 * 666643;
+   s3 += s14 * 470296;
+   s4 += s14 * 654183;
+   s5 -= s14 * 997805;
+   s6 += s14 * 136657;
+   s7 -= s14 * 683901;
+   s14 = 0;
+
+   s1 += s13 * 666643;
+   s2 += s13 * 470296;
+   s3 += s13 * 654183;
+   s4 -= s13 * 997805;
+   s5 += s13 * 136657;
+   s6 -= s13 * 683901;
+   s13 = 0;
+
+   s0 += s12 * 666643;
+   s1 += s12 * 470296;
+   s2 += s12 * 654183;
+   s3 -= s12 * 997805;
+   s4 += s12 * 136657;
+   s5 -= s12 * 683901;
+   s12 = 0;
+
+   carry0 = (s0 + (1<<20)) >> 21;
+   s1 += carry0;
+   s0 -= carry0 << 21;
+   carry2 = (s2 + (1<<20)) >> 21;
+   s3 += carry2;
+   s2 -= carry2 << 21;
+   carry4 = (s4 + (1<<20)) >> 21;
+   s5 += carry4;
+   s4 -= carry4 << 21;
+   carry6 = (s6 + (1<<20)) >> 21;
+   s7 += carry6;
+   s6 -= carry6 << 21;
+   carry8 = (s8 + (1<<20)) >> 21;
+   s9 += carry8;
+   s8 -= carry8 << 21;
+   carry10 = (s10 + (1<<20)) >> 21;
+   s11 += carry10;
+   s10 -= carry10 << 21;
+
+   carry1 = (s1 + (1<<20)) >> 21;
+   s2 += carry1;
+   s1 -= carry1 << 21;
+   carry3 = (s3 + (1<<20)) >> 21;
+   s4 += carry3;
+   s3 -= carry3 << 21;
+   carry5 = (s5 + (1<<20)) >> 21;
+   s6 += carry5;
+   s5 -= carry5 << 21;
+   carry7 = (s7 + (1<<20)) >> 21;
+   s8 += carry7;
+   s7 -= carry7 << 21;
+   carry9 = (s9 + (1<<20)) >> 21;
+   s10 += carry9;
+   s9 -= carry9 << 21;
+   carry11 = (s11 + (1<<20)) >> 21;
+   s12 += carry11;
+   s11 -= carry11 << 21;
+
+   s0 += s12 * 666643;
+   s1 += s12 * 470296;
+   s2 += s12 * 654183;
+   s3 -= s12 * 997805;
+   s4 += s12 * 136657;
+   s5 -= s12 * 683901;
+   s12 = 0;
+
+   carry0 = s0 >> 21;
+   s1 += carry0;
+   s0 -= carry0 << 21;
+   carry1 = s1 >> 21;
+   s2 += carry1;
+   s1 -= carry1 << 21;
+   carry2 = s2 >> 21;
+   s3 += carry2;
+   s2 -= carry2 << 21;
+   carry3 = s3 >> 21;
+   s4 += carry3;
+   s3 -= carry3 << 21;
+   carry4 = s4 >> 21;
+   s5 += carry4;
+   s4 -= carry4 << 21;
+   carry5 = s5 >> 21;
+   s6 += carry5;
+   s5 -= carry5 << 21;
+   carry6 = s6 >> 21;
+   s7 += carry6;
+   s6 -= carry6 << 21;
+   carry7 = s7 >> 21;
+   s8 += carry7;
+   s7 -= carry7 << 21;
+   carry8 = s8 >> 21;
+   s9 += carry8;
+   s8 -= carry8 << 21;
+   carry9 = s9 >> 21;
+   s10 += carry9;
+   s9 -= carry9 << 21;
+   carry10 = s10 >> 21;
+   s11 += carry10;
+   s10 -= carry10 << 21;
+   carry11 = s11 >> 21;
+   s12 += carry11;
+   s11 -= carry11 << 21;
+
+   s0 += s12 * 666643;
+   s1 += s12 * 470296;
+   s2 += s12 * 654183;
+   s3 -= s12 * 997805;
+   s4 += s12 * 136657;
+   s5 -= s12 * 683901;
+   s12 = 0;
+
+   carry0 = s0 >> 21;
+   s1 += carry0;
+   s0 -= carry0 << 21;
+   carry1 = s1 >> 21;
+   s2 += carry1;
+   s1 -= carry1 << 21;
+   carry2 = s2 >> 21;
+   s3 += carry2;
+   s2 -= carry2 << 21;
+   carry3 = s3 >> 21;
+   s4 += carry3;
+   s3 -= carry3 << 21;
+   carry4 = s4 >> 21;
+   s5 += carry4;
+   s4 -= carry4 << 21;
+   carry5 = s5 >> 21;
+   s6 += carry5;
+   s5 -= carry5 << 21;
+   carry6 = s6 >> 21;
+   s7 += carry6;
+   s6 -= carry6 << 21;
+   carry7 = s7 >> 21;
+   s8 += carry7;
+   s7 -= carry7 << 21;
+   carry8 = s8 >> 21;
+   s9 += carry8;
+   s8 -= carry8 << 21;
+   carry9 = s9 >> 21;
+   s10 += carry9;
+   s9 -= carry9 << 21;
+   carry10 = s10 >> 21;
+   s11 += carry10;
+   s10 -= carry10 << 21;
+
+   s[0] = s0 >> 0;
+   s[1] = s0 >> 8;
+   s[2] = (s0 >> 16) | (s1 << 5);
+   s[3] = s1 >> 3;
+   s[4] = s1 >> 11;
+   s[5] = (s1 >> 19) | (s2 << 2);
+   s[6] = s2 >> 6;
+   s[7] = (s2 >> 14) | (s3 << 7);
+   s[8] = s3 >> 1;
+   s[9] = s3 >> 9;
+   s[10] = (s3 >> 17) | (s4 << 4);
+   s[11] = s4 >> 4;
+   s[12] = s4 >> 12;
+   s[13] = (s4 >> 20) | (s5 << 1);
+   s[14] = s5 >> 7;
+   s[15] = (s5 >> 15) | (s6 << 6);
+   s[16] = s6 >> 2;
+   s[17] = s6 >> 10;
+   s[18] = (s6 >> 18) | (s7 << 3);
+   s[19] = s7 >> 5;
+   s[20] = s7 >> 13;
+   s[21] = s8 >> 0;
+   s[22] = s8 >> 8;
+   s[23] = (s8 >> 16) | (s9 << 5);
+   s[24] = s9 >> 3;
+   s[25] = s9 >> 11;
+   s[26] = (s9 >> 19) | (s10 << 2);
+   s[27] = s10 >> 6;
+   s[28] = (s10 >> 14) | (s11 << 7);
+   s[29] = s11 >> 1;
+   s[30] = s11 >> 9;
+   s[31] = s11 >> 17;
+   }
+
+}