tiny_encryption_algorithm.h

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/*
Copyright (C) 2018 Christoph Schied
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
 
uvec2
encrypt_tea(uvec2 arg)
{
    const uint key[] = {
        0xa341316c, 0xc8013ea4, 0xad90777d, 0x7e95761e
    };
    uint v0 = arg[0], v1 = arg[1];
    uint sum = 0;
    uint delta = 0x9e3779b9;
 
    #pragma unroll
    for(int i = 0; i < 16; i++) {
    //for(int i = 0; i < 32; i++) {
        sum += delta;
        v0 += ((v1 << 4) + key[0]) ^ (v1 + sum) ^ ((v1 >> 5) + key[1]);
        v1 += ((v0 << 4) + key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + key[3]);
    }
    return uvec2(v0, v1);
}