diff --git a/src/key_io.cpp b/src/key_io.cpp
new file mode 100644
index 000000000..c2dc51198
--- /dev/null
+++ b/src/key_io.cpp
@@ -0,0 +1,227 @@
+// Copyright (c) 2014-2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <key_io.h>
+
+#include <base58.h>
+#include <bech32.h>
+#include <script/script.h>
+#include <utilstrencodings.h>
+
+#include <boost/variant/apply_visitor.hpp>
+#include <boost/variant/static_visitor.hpp>
+
+#include <assert.h>
+#include <string.h>
+#include <algorithm>
+
+namespace
+{
+class DestinationEncoder : public boost::static_visitor<std::string>
+{
+private:
+    const CChainParams& m_params;
+
+public:
+    DestinationEncoder(const CChainParams& params) : m_params(params) {}
+
+    std::string operator()(const CKeyID& id) const
+    {
+        std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
+        data.insert(data.end(), id.begin(), id.end());
+        return EncodeBase58Check(data);
+    }
+
+    std::string operator()(const CScriptID& id) const
+    {
+        std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
+        data.insert(data.end(), id.begin(), id.end());
+        return EncodeBase58Check(data);
+    }
+
+    std::string operator()(const WitnessV0KeyHash& id) const
+    {
+        std::vector<unsigned char> data = {0};
+        data.reserve(33);
+        ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
+        return bech32::Encode(m_params.Bech32HRP(), data);
+    }
+
+    std::string operator()(const WitnessV0ScriptHash& id) const
+    {
+        std::vector<unsigned char> data = {0};
+        data.reserve(53);
+        ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
+        return bech32::Encode(m_params.Bech32HRP(), data);
+    }
+
+    std::string operator()(const WitnessUnknown& id) const
+    {
+        if (id.version < 1 || id.version > 16 || id.length < 2 || id.length > 40) {
+            return {};
+        }
+        std::vector<unsigned char> data = {(unsigned char)id.version};
+        data.reserve(1 + (id.length * 8 + 4) / 5);
+        ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.program, id.program + id.length);
+        return bech32::Encode(m_params.Bech32HRP(), data);
+    }
+
+    std::string operator()(const CNoDestination& no) const { return {}; }
+};
+
+CTxDestination DecodeDestination(const std::string& str, const CChainParams& params)
+{
+    std::vector<unsigned char> data;
+    uint160 hash;
+    if (DecodeBase58Check(str, data)) {
+        // base58-encoded Bitcoin addresses.
+        // Public-key-hash-addresses have version 0 (or 111 testnet).
+        // The data vector contains RIPEMD160(SHA256(pubkey)), where pubkey is the serialized public key.
+        const std::vector<unsigned char>& pubkey_prefix = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
+        if (data.size() == hash.size() + pubkey_prefix.size() && std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin())) {
+            std::copy(data.begin() + pubkey_prefix.size(), data.end(), hash.begin());
+            return CKeyID(hash);
+        }
+        // Script-hash-addresses have version 5 (or 196 testnet).
+        // The data vector contains RIPEMD160(SHA256(cscript)), where cscript is the serialized redemption script.
+        const std::vector<unsigned char>& script_prefix = params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
+        if (data.size() == hash.size() + script_prefix.size() && std::equal(script_prefix.begin(), script_prefix.end(), data.begin())) {
+            std::copy(data.begin() + script_prefix.size(), data.end(), hash.begin());
+            return CScriptID(hash);
+        }
+    }
+    data.clear();
+    auto bech = bech32::Decode(str);
+    if (bech.second.size() > 0 && bech.first == params.Bech32HRP()) {
+        // Bech32 decoding
+        int version = bech.second[0]; // The first 5 bit symbol is the witness version (0-16)
+        // The rest of the symbols are converted witness program bytes.
+        data.reserve(((bech.second.size() - 1) * 5) / 8);
+        if (ConvertBits<5, 8, false>([&](unsigned char c) { data.push_back(c); }, bech.second.begin() + 1, bech.second.end())) {
+            if (version == 0) {
+                {
+                    WitnessV0KeyHash keyid;
+                    if (data.size() == keyid.size()) {
+                        std::copy(data.begin(), data.end(), keyid.begin());
+                        return keyid;
+                    }
+                }
+                {
+                    WitnessV0ScriptHash scriptid;
+                    if (data.size() == scriptid.size()) {
+                        std::copy(data.begin(), data.end(), scriptid.begin());
+                        return scriptid;
+                    }
+                }
+                return CNoDestination();
+            }
+            if (version > 16 || data.size() < 2 || data.size() > 40) {
+                return CNoDestination();
+            }
+            WitnessUnknown unk;
+            unk.version = version;
+            std::copy(data.begin(), data.end(), unk.program);
+            unk.length = data.size();
+            return unk;
+        }
+    }
+    return CNoDestination();
+}
+} // namespace
+
+CKey DecodeSecret(const std::string& str)
+{
+    CKey key;
+    std::vector<unsigned char> data;
+    if (DecodeBase58Check(str, data)) {
+        const std::vector<unsigned char>& privkey_prefix = Params().Base58Prefix(CChainParams::SECRET_KEY);
+        if ((data.size() == 32 + privkey_prefix.size() || (data.size() == 33 + privkey_prefix.size() && data.back() == 1)) &&
+            std::equal(privkey_prefix.begin(), privkey_prefix.end(), data.begin())) {
+            bool compressed = data.size() == 33 + privkey_prefix.size();
+            key.Set(data.begin() + privkey_prefix.size(), data.begin() + privkey_prefix.size() + 32, compressed);
+        }
+    }
+    memory_cleanse(data.data(), data.size());
+    return key;
+}
+
+std::string EncodeSecret(const CKey& key)
+{
+    assert(key.IsValid());
+    std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::SECRET_KEY);
+    data.insert(data.end(), key.begin(), key.end());
+    if (key.IsCompressed()) {
+        data.push_back(1);
+    }
+    std::string ret = EncodeBase58Check(data);
+    memory_cleanse(data.data(), data.size());
+    return ret;
+}
+
+CExtPubKey DecodeExtPubKey(const std::string& str)
+{
+    CExtPubKey key;
+    std::vector<unsigned char> data;
+    if (DecodeBase58Check(str, data)) {
+        const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
+        if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
+            key.Decode(data.data() + prefix.size());
+        }
+    }
+    return key;
+}
+
+std::string EncodeExtPubKey(const CExtPubKey& key)
+{
+    std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
+    size_t size = data.size();
+    data.resize(size + BIP32_EXTKEY_SIZE);
+    key.Encode(data.data() + size);
+    std::string ret = EncodeBase58Check(data);
+    return ret;
+}
+
+CExtKey DecodeExtKey(const std::string& str)
+{
+    CExtKey key;
+    std::vector<unsigned char> data;
+    if (DecodeBase58Check(str, data)) {
+        const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
+        if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
+            key.Decode(data.data() + prefix.size());
+        }
+    }
+    return key;
+}
+
+std::string EncodeExtKey(const CExtKey& key)
+{
+    std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
+    size_t size = data.size();
+    data.resize(size + BIP32_EXTKEY_SIZE);
+    key.Encode(data.data() + size);
+    std::string ret = EncodeBase58Check(data);
+    memory_cleanse(data.data(), data.size());
+    return ret;
+}
+
+std::string EncodeDestination(const CTxDestination& dest)
+{
+    return boost::apply_visitor(DestinationEncoder(Params()), dest);
+}
+
+CTxDestination DecodeDestination(const std::string& str)
+{
+    return DecodeDestination(str, Params());
+}
+
+bool IsValidDestinationString(const std::string& str, const CChainParams& params)
+{
+    return IsValidDestination(DecodeDestination(str, params));
+}
+
+bool IsValidDestinationString(const std::string& str)
+{
+    return IsValidDestinationString(str, Params());
+}
diff --git a/src/key_io.h b/src/key_io.h
new file mode 100644
index 000000000..6fc9a8059
--- /dev/null
+++ b/src/key_io.h
@@ -0,0 +1,29 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2015 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KEYIO_H
+#define BITCOIN_KEYIO_H
+
+#include <chainparams.h>
+#include <key.h>
+#include <pubkey.h>
+#include <script/standard.h>
+
+#include <string>
+
+CKey DecodeSecret(const std::string& str);
+std::string EncodeSecret(const CKey& key);
+
+CExtKey DecodeExtKey(const std::string& str);
+std::string EncodeExtKey(const CExtKey& extkey);
+CExtPubKey DecodeExtPubKey(const std::string& str);
+std::string EncodeExtPubKey(const CExtPubKey& extpubkey);
+
+std::string EncodeDestination(const CTxDestination& dest);
+CTxDestination DecodeDestination(const std::string& str);
+bool IsValidDestinationString(const std::string& str);
+bool IsValidDestinationString(const std::string& str, const CChainParams& params);
+
+#endif // BITCOIN_KEYIO_H