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crypto: encrypt in-place where it suits

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This commit is contained in:
Danny Robson 2015-05-15 18:26:45 +10:00
parent 9a1a75d623
commit 7f0c7466e4
6 changed files with 44 additions and 53 deletions
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34
crypto/tea.cpp
View File

@ -37,16 +37,16 @@ TEA::TEA (key_t _key):
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
void void
TEA::encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count) TEA::encrypt (uint32_t *restrict data, size_t count)
{ {
if (count % 2) if (count % 2)
throw std::invalid_argument ("TEA requires even data count"); throw std::invalid_argument ("TEA requires even data count");
auto last = src + count; auto last = data + count;
while (src < last) { while (data < last) {
uint32_t sum = 0; uint32_t sum = 0;
uint32_t v0 = src[0]; uint32_t v0 = data[0];
uint32_t v1 = src[1]; uint32_t v1 = data[1];
for (unsigned i = 0; i < ITERATIONS; ++i) { for (unsigned i = 0; i < ITERATIONS; ++i) {
sum += MAGIC; sum += MAGIC;
@ -54,28 +54,25 @@ TEA::encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count
v1 += ((v0 << 4) + m_key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + m_key[3]); v1 += ((v0 << 4) + m_key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + m_key[3]);
} }
dst[0] = v0; *data++ = v0;
dst[1] = v1; *data++ = v1;
src += 2;
dst += 2;
} }
} }
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
void void
TEA::decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count) TEA::decrypt (uint32_t *restrict data, size_t count)
{ {
if (count % 2) if (count % 2)
throw std::invalid_argument ("TEA requires even data count"); throw std::invalid_argument ("TEA requires even data count");
auto last = src + count; auto last = data + count;
while (src < last) { while (data < last) {
uint32_t sum = MAGIC << 5; uint32_t sum = MAGIC << 5;
uint32_t v0 = src[0]; uint32_t v0 = data[0];
uint32_t v1 = src[1]; uint32_t v1 = data[1];
for (unsigned i = 0; i < ITERATIONS; ++i) { for (unsigned i = 0; i < ITERATIONS; ++i) {
v1 -= ((v0 << 4) + m_key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + m_key[3]); v1 -= ((v0 << 4) + m_key[2]) ^ (v0 + sum) ^ ((v0 >> 5) + m_key[3]);
@ -83,10 +80,7 @@ TEA::decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count
sum -= MAGIC; sum -= MAGIC;
} }
dst[0] = v0; *data++ = v0;
dst[1] = v1; *data++ = v1;
src += 2;
dst += 2;
} }
} }

4
crypto/tea.hpp
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@ -29,8 +29,8 @@ namespace util { namespace crypto {
TEA (key_t); TEA (key_t);
void encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count); void encrypt (uint32_t *restrict data, size_t count);
void decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count); void decrypt (uint32_t *restrict data, size_t count);
private: private:
key_t m_key; key_t m_key;

33
crypto/xtea.cpp
View File

@ -34,17 +34,17 @@ XTEA::XTEA (key_t _key):
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
void void
XTEA::encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count) XTEA::encrypt (uint32_t *restrict data, size_t count)
{ {
if (count % 2) if (count % 2)
throw std::invalid_argument ("XTEA requires even data count"); throw std::invalid_argument ("XTEA requires even data count");
auto last = src + count; auto last = data + count;
while (src < last) { while (data < last) {
uint32_t sum = 0; uint32_t sum = 0;
uint32_t v0 = src[0]; uint32_t v0 = data[0];
uint32_t v1 = src[1]; uint32_t v1 = data[1];
for (unsigned i = 0; i < ITERATIONS; ++i) { for (unsigned i = 0; i < ITERATIONS; ++i) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + m_key[sum & 3]); v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + m_key[sum & 3]);
@ -52,28 +52,25 @@ XTEA::encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t coun
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + m_key[(sum >> 11) & 3]); v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + m_key[(sum >> 11) & 3]);
} }
dst[0] = v0; *data++ = v0;
dst[1] = v1; *data++ = v1;
src += 2;
dst += 2;
} }
} }
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
void void
XTEA::decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count) XTEA::decrypt (uint32_t *restrict data, size_t count)
{ {
if (count % 2) if (count % 2)
throw std::invalid_argument ("XTEA requires even data count"); throw std::invalid_argument ("XTEA requires even data count");
auto last = src + count; auto last = data + count;
while (src < last) { while (data < last) {
uint32_t sum = ITERATIONS * MAGIC; uint32_t sum = ITERATIONS * MAGIC;
uint32_t v0 = src[0]; uint32_t v0 = data[0];
uint32_t v1 = src[1]; uint32_t v1 = data[1];
for (unsigned i = 0; i < ITERATIONS; ++i) { for (unsigned i = 0; i < ITERATIONS; ++i) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + m_key[(sum >> 11) & 3]); v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + m_key[(sum >> 11) & 3]);
@ -81,9 +78,7 @@ XTEA::decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t coun
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + m_key[sum & 3]); v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + m_key[sum & 3]);
} }
dst[0] = v0; *data++ = v0;
dst[1] = v1; *data++ = v1;
src += 2;
} }
} }

4
crypto/xtea.hpp
View File

@ -29,8 +29,8 @@ namespace util { namespace crypto {
XTEA (key_t); XTEA (key_t);
void encrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count); void encrypt (uint32_t *restrict data, size_t count);
void decrypt (uint32_t *restrict dst, const uint32_t *restrict src, size_t count); void decrypt (uint32_t *restrict data, size_t count);
private: private:
key_t m_key; key_t m_key;

9
test/crypto/tea.cpp
View File

@ -7,7 +7,7 @@ int
main () main ()
{ {
// test vectors from 'TeaCrypt', by Logan J. Drews. // test vectors from 'TeaCrypt', by Logan J. Drews.
struct { static const struct {
std::array<uint32_t,4> key; std::array<uint32_t,4> key;
std::array<uint32_t,2> dec; std::array<uint32_t,2> dec;
std::array<uint32_t,2> enc; std::array<uint32_t,2> enc;
@ -44,10 +44,11 @@ main ()
const auto &t = TESTS[i]; const auto &t = TESTS[i];
util::crypto::TEA gen (t.key); util::crypto::TEA gen (t.key);
std::array<uint32_t,2> enc, dec; std::array<uint32_t,2> enc (t.dec);
gen.encrypt (enc.data (), enc.size ());
gen.encrypt (enc.data (), t.dec.data (), t.dec.size ()); std::array<uint32_t,2> dec (t.enc);
gen.decrypt (dec.data (), t.enc.data (), t.enc.size ()); gen.decrypt (dec.data (), dec.size ());
{ {
std::ostringstream os; std::ostringstream os;

13
test/crypto/xtea.cpp
View File

@ -6,7 +6,7 @@ int
main () main ()
{ {
// test vectors from 'TeaCrypt', by Logan J. Drews. // test vectors from 'TeaCrypt', by Logan J. Drews.
struct { static const struct {
std::array<uint32_t,4> key; std::array<uint32_t,4> key;
std::array<uint32_t,2> dec; std::array<uint32_t,2> dec;
std::array<uint32_t,2> enc; std::array<uint32_t,2> enc;
@ -43,20 +43,21 @@ main ()
const auto &t = TESTS[i]; const auto &t = TESTS[i];
util::crypto::XTEA gen (t.key); util::crypto::XTEA gen (t.key);
std::array<uint32_t,2> enc, dec; std::array<uint32_t,2> enc (t.dec);
gen.encrypt (enc.data (), enc.size ());
gen.encrypt (enc.data (), t.dec.data (), t.dec.size ()); std::array<uint32_t,2> dec (t.enc);
gen.decrypt (dec.data (), t.enc.data (), t.enc.size ()); gen.decrypt (dec.data (), dec.size ());
{ {
std::ostringstream os; std::ostringstream os;
os << "TEA_enc " << i; os << "XTEA_enc " << i;
tap.expect (enc == t.enc, os.str ()); tap.expect (enc == t.enc, os.str ());
} }
{ {
std::ostringstream os; std::ostringstream os;
os << "TEA_dec " << i; os << "XTEA_dec " << i;
tap.expect (dec == t.dec, os.str ()); tap.expect (dec == t.dec, os.str ());
} }
} }