crypto: add XXTEA {en,de}cryption.

Makefile.am

@@ -29,6 +29,8 @@ UTIL_FILES   =		\
     crypto/tea.hpp	\
     crypto/xtea.cpp	\
     crypto/xtea.hpp	\
+    crypto/xxtea.cpp	\
+    crypto/xxtea.hpp	\
     crypto/arc4.cpp	\
     crypto/arc4.hpp	\
     debug.cpp   	\
@@ -270,6 +272,7 @@ TEST_BIN = 			\
     test/crypto/arc4		\
     test/crypto/tea		\
     test/crypto/xtea		\
+    test/crypto/xxtea		\
     test/extent			\
     test/fixed			\
     test/float			\

crypto/xxtea.cpp

@@ -0,0 +1,104 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "xxtea.hpp"
+
+#include <cstring>
+
+// test vectors: http://www.cix.co.uk/~klockstone/teavect.htm
+
+using util::crypto::XXTEA;
+
+
+//-----------------------------------------------------------------------------
+static const uint32_t MAGIC = 0x9E3779B9;
+static const unsigned ITERATIONS = 32; // each iteration performs two feistel rounds
+
+
+//-----------------------------------------------------------------------------
+static constexpr uint32_t mix (uint32_t Z,
+                               uint32_t Y,
+                               uint32_t S,
+                               size_t E,
+                               size_t P,
+                               const uint32_t *restrict K)
+{
+    return ((Z >> 5 ^ Y << 2) + (Y >> 3 ^ Z << 4)) ^ ((S ^ Y) + (K[(P & 3) ^ E] ^ Z));
+}
+
+
+//-----------------------------------------------------------------------------
+XXTEA::XXTEA (key_t _key):
+    m_key (_key)
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+void
+XXTEA::encrypt (uint32_t *restrict data, size_t count)
+{
+    if (count < 2)
+        throw std::invalid_argument ("minimum blocksize is 64 bits");
+
+    uint32_t sum = 0;
+    uint32_t z = data[count - 1];
+    uint32_t y, e, p;
+
+    unsigned rounds = 6 + 52 / count;
+
+    do {
+        sum += MAGIC;
+        e = (sum >> 2) & 3;
+
+        for (p = 0; p < count - 1; p++) {
+            y = data[p + 1];
+            z = data[p] += mix (z, y, sum, e, p, m_key.data ());
+        }
+
+        y = data[0];
+        z = data[count - 1] += mix (z, y, sum, e, p, m_key.data ());
+    } while (--rounds);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+XXTEA::decrypt (uint32_t *restrict data, size_t count)
+{
+    if (count < 2)
+        throw std::invalid_argument ("minimum blocksize is 64 bits");
+
+    uint32_t y, z, sum;
+    unsigned p, rounds, e;
+
+    rounds = 6 + 52 / count;
+    sum = rounds * MAGIC;
+    y = data[0];
+
+    do {
+        e = (sum >> 2) & 3;
+
+        for (p = count - 1; p > 0; p--) {
+            z = data[p - 1];
+            y = data[p    ] -= mix (z, y, sum, e, p, m_key.data ());
+        }
+
+        z = data[count - 1];
+        y = data[        0] -= mix (z, y, sum, e, p, m_key.data ());
+
+        sum -= MAGIC;
+    } while (--rounds);
+}

crypto/xxtea.hpp

@@ -0,0 +1,42 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_TEA_HPP
+#define __UTIL_TEA_HPP
+
+#include <array>
+#include <cstdint>
+#include <cstddef>
+
+namespace util { namespace crypto {
+    // http://en.wikipedia.org/wiki/XXTEA
+    // 'corrected' block TEA
+    class XXTEA {
+    public:
+        using key_t = std::array<uint32_t,4>;
+
+        XXTEA (key_t);
+
+        void encrypt (uint32_t *restrict data, size_t count);
+        void decrypt (uint32_t *restrict data, size_t count);
+
+    private:
+        key_t m_key;
+    };
+} }
+
+#endif
+

test/crypto/xxtea.cpp

@@ -0,0 +1,121 @@
+#include "crypto/xxtea.hpp"
+
+#include "tap.hpp"
+#include "types.hpp"
+
+
+int
+main ()
+{
+    // test vectors from 'TeaCrypt', by Logan J. Drews.
+    static const struct {
+        std::array<uint32_t,4> key;
+        std::vector<uint32_t> dec;
+        std::vector<uint32_t> enc;
+    } TESTS[] = {
+        // 64 bit
+        {
+            { 0x00000000, 0x00000000, 0x00000000, 0x00000000 },
+            { 0x00000000, 0x00000000 },
+            { 0x053704AB, 0x575D8C80 }
+        },
+
+        {
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0x01020304, 0x05060708},
+            {0xE6911910, 0x0C35DCDA},
+        },
+          
+        {
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x01020304, 0x05060708},
+            {0x961D49FC, 0x61FF12D6},
+        },
+
+        {            
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x01234567, 0x89ABCDEF},
+            {0x34354989, 0xDD7D1A7A},
+        },
+
+        // 96 bit
+        {
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0x00000000, 0x00000000, 0x00000000},
+            {0x5E3CD3F0, 0xE109E3CE, 0x79D7C945},
+        },
+
+        {
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0x00010203, 0x04050607, 0x08090A0B},
+            {0x5A545AAC, 0x684EB2CB, 0x3E1B8AA0},
+        },
+
+        {
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x00010203, 0x04050607, 0x08090A0B},
+            {0x2E77CCEC, 0x674F5149, 0xA0E56496},
+        },
+
+        {
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x01234567, 0x89ABCDEF, 0x01234567},
+            {0xEBC5DD46, 0xBE0FEE71, 0xC6BF7193},
+        },
+
+        // 128 bit
+        {
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0xE6C8D5FF, 0x070FB6E4, 0x98A534F7, 0xAC03E399},
+        },
+
+        {
+            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
+            {0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F},
+            {0xAF5CFB0E, 0xAE73552B, 0x1D968A9F, 0x5CB94509},
+        },
+
+        {
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F},
+            {0x3EA0E16C, 0x9969535A, 0xE4796D50, 0xF217EEEA},
+        },
+
+        {
+            {0x00112233, 0x44556677, 0x8899AABB, 0xCCDDEEFF},
+            {0x01234567, 0x89ABCDEF, 0x01234567, 0x89ABCDEF},
+            {0x2B4AB1A4, 0x0E487B6D, 0x9A3AACC7, 0xE4132216},
+        },
+    };
+
+    util::TAP::logger tap;
+
+    for (size_t i = 0; i < elems (TESTS); ++i) {
+        const auto &t = TESTS[i];
+
+        CHECK_EQ (t.dec.size (), t.enc.size ());
+
+        util::crypto::XXTEA gen (t.key);
+
+        std::vector<uint32_t> enc (t.dec);
+        gen.encrypt (enc.data (), enc.size ());
+
+        std::vector<uint32_t> dec (enc);
+        gen.decrypt (dec.data (), dec.size ());
+
+        {
+            std::ostringstream os;
+            os << "XXTEA_enc " << i;
+            tap.expect (enc == t.enc, os.str ());
+        }
+
+        {
+            std::ostringstream os;
+            os << "XXTEA_dec " << i;
+            tap.expect (dec == t.dec, os.str ());
+        }
+    }
+
+    return tap.status ();
+}