New serialized object, public key, and private key interfaces

This introduces functions get and set, and a family of specialized
structs called STExchange. These interfaces allow efficient and
seamless interchange between serialized object fields and user
defined types, especially variable length objects.

A new base class template TypedField is mixed into existing SField
declarations to encode information on the field, allowing template
metaprograms to both customize interchange based on the type and
detect misuse at compile-time.

New types AnyPublicKey and AnySecretKey are introduced. These are
intended to replace the corresponding functionality in the deprecated
class RippleAddress. Specializations of STExchange for these types
are provided to allow interchange. New free functions verify and sign
allow signature verification and signature generation for serialized
objects.

* Add Buffer and Slice primitives
* Add TypedField and modify some SField
* Add STExchange and specializations for STBlob and STInteger
* Improve STBlob and STInteger to support STExchange
* Expose raw data in RippleAddress and Serializer

src/ripple/protocol/impl/AnySecretKey.cpp

@@ -0,0 +1,143 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/protocol/AnySecretKey.h>
+#include <ripple/protocol/RippleAddress.h>
+#include <ripple/protocol/Serializer.h>
+#include <ripple/crypto/RandomNumbers.h>
+#include <ed25519-donna/ed25519.h>
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+
+namespace ripple {
+
+AnySecretKey::~AnySecretKey()
+{
+    // secure erase
+    std::fill(p_.data(), p_.data() + p_.size(), 0);
+}
+
+AnySecretKey::AnySecretKey (AnySecretKey&& other)
+    : p_ (std::move(other.p_))
+    , type_ (other.type_)
+{
+    other.type_ = KeyType::unknown;
+}
+
+AnySecretKey&
+AnySecretKey::operator= (AnySecretKey&& other)
+{
+    p_ = std::move(other.p_);
+    type_ = other.type_;
+    other.type_ = KeyType::unknown;
+    return *this;
+}
+
+AnySecretKey::AnySecretKey (KeyType type,
+        void const* data, std::size_t size)
+    : p_ (data, size)
+    , type_ (type)
+{
+    if (type_ == KeyType::unknown)
+        throw std::runtime_error(
+            "AnySecretKey: unknown type");
+    if (type_ == KeyType::ed25519 &&
+            size != 32)
+        throw std::runtime_error(
+            "AnySecretKey: wrong ed25519 size");
+    if (type_ == KeyType::secp256k1 &&
+            size != 32)
+        throw std::runtime_error(
+            "AnySecretKey: wrong secp256k1 size");
+}
+
+AnyPublicKey
+AnySecretKey::publicKey() const
+{
+    switch (type())
+    {
+    case KeyType::ed25519:
+    {
+        unsigned char buf[33];
+        buf[0] = 0xED;
+        ed25519_publickey(p_.data() + 1, &buf[1]);
+        return AnyPublicKey(buf, sizeof(buf));
+    }
+    default:
+        throw std::runtime_error(
+            "AnySecretKey: unknown type");
+    };
+}
+
+Buffer
+AnySecretKey::sign (
+    void const* msg, std::size_t msg_len) const
+{
+    switch(type_)
+    {
+        case KeyType::ed25519:
+        {
+            auto const sk = p_.data() + 1;
+            ed25519_public_key pk;
+            ed25519_publickey(sk, pk);
+            Buffer b(64);
+            ed25519_sign(reinterpret_cast<
+                unsigned char const*>(msg), msg_len,
+                    sk, pk, b.data());
+            return b;
+        }
+        default:
+            break;
+    }
+    throw std::runtime_error(
+        "AnySecretKey: unknown type");
+}
+
+AnySecretKey
+AnySecretKey::make_ed25519()
+{
+    std::uint8_t buf[32];
+    random_fill(&buf[0], sizeof(buf));
+    AnySecretKey ask(KeyType::ed25519,
+        buf, sizeof(buf));
+    // secure erase
+    std::fill(buf, buf + sizeof(buf), 0);
+    return ask;
+}
+
+std::pair<AnySecretKey, AnyPublicKey>
+AnySecretKey::make_secp256k1_pair()
+{
+    // VFALCO What a pile
+    RippleAddress s;
+    s.setSeedRandom();
+    RippleAddress const g =
+        RippleAddress::createGeneratorPublic(s);
+    RippleAddress sk;
+    sk.setAccountPrivate (g, s, 0);
+    RippleAddress pk;
+    pk.setAccountPublic (g, 0);
+    return std::pair<AnySecretKey, AnyPublicKey>(
+        std::piecewise_construct, std::make_tuple(
+            KeyType::secp256k1, sk.data(), sk.size()),
+                std::make_tuple(pk.data(), pk.size()));
+}
+
+} // ripple