63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
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#include <stdint.h>
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void TEA_encrypt (uint32_t block[2], uint32_t key[4])
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{
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/* set up */
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uint32_t v0 = block[0];
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uint32_t v1 = block[1];
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uint32_t sum = 0;
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uint32_t i;
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/* a key schedule constant */
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uint32_t delta = 0x9e3779b9;
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/* cache key */
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uint32_t k0 = key[0];
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uint32_t k1 = key[1];
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uint32_t k2 = key[2];
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uint32_t k3 = key[3];
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/* basic cycle start */
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for (i = 0; i < 32; i++)
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{
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sum += delta;
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v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
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v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
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}
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/* end cycle */
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block[0] = v0;
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block[1] = v1;
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}
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void TEA_decrypt (uint32_t* block, uint32_t* key)
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{
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/* set up */
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uint32_t v0 = block[0];
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uint32_t v1 = block[1];
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uint32_t sum = 0xC6EF3720;
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uint32_t i;
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/* a key schedule constant */
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uint32_t delta = 0x9e3779b9;
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/* cache key */
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uint32_t k0 = key[0];
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uint32_t k1 = key[1];
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uint32_t k2 = key[2];
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uint32_t k3 = key[3];
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/* basic cycle start */
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for (i = 0; i < 32; i++)
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{
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v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
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v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
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sum -= delta;
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}
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/* end cycle */
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block[0] = v0;
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block[1] = v1;
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}
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