hash/hmac: add simple HMAC-MD5

Makefile.am

@@ -45,6 +45,8 @@ UTIL_FILES   =		\
     hash/crc.cpp	\
     hash/crc.hpp	\
     hash/fletcher.hpp	\
+    hash/hmac.cpp	\
+    hash/hmac.hpp	\
     hash/md2.cpp	\
     hash/md2.hpp	\
     hash/md4.cpp	\
@@ -238,6 +240,7 @@ TEST_BIN = 			\
     test/extent			\
     test/fixed			\
     test/float			\
+    test/hmac			\
     test/hton			\
     test/ip 			\
     test/json_types		\

hash/hmac.cpp

@@ -0,0 +1,102 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim 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 3 of the License, or (at your option) any later
+ * version.
+ * 
+ * libgim 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 libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "hmac.hpp"
+
+#include "debug.hpp"
+
+#include <algorithm>
+
+using util::hash::HMAC;
+
+
+//-----------------------------------------------------------------------------
+static const uint8_t IFILL = 0x36;
+static const uint8_t OFILL = 0x5C;
+
+
+//-----------------------------------------------------------------------------
+HMAC::HMAC (const uint8_t *restrict key, size_t len)
+{
+    CHECK (key);
+    CHECK_LE (len, m_ikey.size ());
+    CHECK_LE (len, m_okey.size ());
+
+    static_assert (sizeof (m_ikey) == sizeof (m_okey), "key padding must match");
+
+    
+    std::copy (key, key + len, m_ikey.begin ());
+    std::fill (m_ikey.begin () + len,
+               m_ikey.end (),
+               0);
+
+    m_okey = m_ikey;
+
+    std::transform (m_ikey.begin (),
+                    m_ikey.end (),
+                    m_ikey.begin (),
+                    [] (auto v) { return v ^ IFILL; });
+
+    std::transform (m_okey.begin (),
+                    m_okey.end (),
+                    m_okey.begin (),
+                    [] (auto v) { return v ^ OFILL; });
+
+    m_hash.update (m_ikey.data (), m_ikey.size ());
+}
+
+
+
+//-----------------------------------------------------------------------------
+void
+HMAC::update (const void *restrict data, size_t len)
+{
+    m_hash.update ((const uint8_t*)data, len);
+}
+
+
+//-----------------------------------------------------------------------------
+void
+HMAC::finish (void)
+{
+    m_hash.finish ();
+    auto d = m_hash.digest ();
+
+    m_hash.reset ();
+    m_hash.update (m_okey.data (), m_okey.size ());
+    m_hash.update (d.data (), d.size ());
+    m_hash.finish ();
+}
+
+
+//-----------------------------------------------------------------------------
+void
+HMAC::reset (void)
+{
+    m_hash.reset ();
+    m_hash.update (m_ikey.data (), m_ikey.size ());
+}
+
+
+//-----------------------------------------------------------------------------
+HMAC::digest_t
+HMAC::digest (void)
+{
+    return m_hash.digest ();
+}

hash/hmac.hpp

@@ -0,0 +1,47 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim 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 3 of the License, or (at your option) any later
+ * version.
+ * 
+ * libgim 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 libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_HASH_HMAC_HPP
+#define __UTIL_HASH_HMAC_HPP
+
+#include "md5.hpp"
+
+namespace util { namespace hash {
+    /// RFC 2104 key-hashing for message authentication
+    class HMAC {
+    public:
+        using digest_t = MD5::digest_t;
+
+        HMAC (const uint8_t *key, size_t);
+
+        void update (const void *restrict, size_t);
+        void finish (void);
+        void reset (void);
+
+        digest_t digest (void);
+
+    private:
+        std::array<uint8_t,64> m_ikey;
+        std::array<uint8_t,64> m_okey;
+
+        MD5 m_hash;
+    };
+} }
+
+#endif

test/hmac.cpp

@@ -0,0 +1,67 @@
+#include "hash/hmac.hpp"
+#include "types.hpp"
+#include "debug.hpp"
+
+#include <iostream>
+#include <vector>
+
+using util::hash::HMAC;
+
+
+static const struct {
+    std::vector<uint8_t> key;
+    std::vector<uint8_t> dat;
+    HMAC::digest_t res;
+} TESTS[] = {
+    // RFC 2104 test data, MD5
+    {
+        { 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+          0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b  },
+        { 'H', 'i', ' ', 'T', 'h', 'e', 'r', 'e' },
+        { { 0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c,
+            0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d } }
+    },
+
+    {
+        { 'J', 'e', 'f', 'e' },
+        { 'w', 'h', 'a', 't', ' ', 'd', 'o', ' ',
+          'y', 'a', ' ', 'w', 'a', 'n', 't', ' ',
+          'f', 'o', 'r', ' ', 'n', 'o', 't', 'h',
+          'i', 'n', 'g', '?' },
+        { { 0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03,
+            0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 } }
+    },
+
+    {
+        { 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
+          0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA  },
+        { 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD,
+          0xDD, 0xDD },
+        { { 0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88,
+            0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 } }
+    }
+};
+
+
+
+
+
+int
+main (int, char**)
+{
+    for (const auto &t: TESTS) {
+        util::hash::HMAC h (t.key.data (), t.key.size ());
+        h.update (t.dat.data (), t.dat.size ());
+        h.finish ();
+
+        if (h.digest () != t.res)
+            return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}