86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
#include <sodium.h>
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#include <erl_nif.h>
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#include "enacl.h"
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#include "enacl_ext.h"
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static void uint64_pack(unsigned char *y, ErlNifUInt64 x) {
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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x >>= 8;
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*y++ = x;
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}
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static ErlNifUInt64 uint64_unpack(const unsigned char *x) {
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ErlNifUInt64 result;
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result = x[7];
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result <<= 8;
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result |= x[6];
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result <<= 8;
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result |= x[5];
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result <<= 8;
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result |= x[4];
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result <<= 8;
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result |= x[3];
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result <<= 8;
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result |= x[2];
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result <<= 8;
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result |= x[1];
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result <<= 8;
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result |= x[0];
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return result;
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}
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static int crypto_block(unsigned char *out, const unsigned char *in,
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const unsigned char *k) {
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ErlNifUInt64 v0 = uint64_unpack(in + 0);
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ErlNifUInt64 v1 = uint64_unpack(in + 8);
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ErlNifUInt64 k0 = uint64_unpack(k + 0);
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ErlNifUInt64 k1 = uint64_unpack(k + 8);
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ErlNifUInt64 k2 = uint64_unpack(k + 16);
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ErlNifUInt64 k3 = uint64_unpack(k + 24);
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ErlNifUInt64 sum = 0;
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ErlNifUInt64 delta = 0x9e3779b97f4a7c15;
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int i;
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for (i = 0; i < 32; ++i) {
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sum += delta;
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v0 += ((v1 << 7) + k0) ^ (v1 + sum) ^ ((v1 >> 12) + k1);
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v1 += ((v0 << 16) + k2) ^ (v0 + sum) ^ ((v0 >> 8) + k3);
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}
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uint64_pack(out + 0, v0);
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uint64_pack(out + 8, v1);
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return 0;
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}
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ERL_NIF_TERM enif_scramble_block_16(ErlNifEnv *env, int argc,
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ERL_NIF_TERM const argv[]) {
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ErlNifBinary in, out, key;
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if ((argc != 2) || (!enif_inspect_binary(env, argv[0], &in)) ||
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(!enif_inspect_binary(env, argv[1], &key)) || (in.size != 16) ||
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(key.size != 32)) {
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return enif_make_badarg(env);
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}
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if (!enif_alloc_binary(in.size, &out)) {
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return enacl_internal_error(env);
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}
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crypto_block(out.data, in.data, key.data);
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return enif_make_binary(env, &out);
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} |