diff --git a/src/Makefile.am b/src/Makefile.am
index 8de7f7ff7a0..0a9370c85c7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -105,6 +105,7 @@ BITCOIN_CORE_H = \
   indirectmap.h \
   init.h \
   key.h \
+  key_io.h \
   keystore.h \
   dbwrapper.h \
   limitedmap.h \
@@ -327,6 +328,7 @@ libbitcoin_common_a_SOURCES = \
   core_read.cpp \
   core_write.cpp \
   key.cpp \
+  key_io.cpp \
   keystore.cpp \
   netaddress.cpp \
   netbase.cpp \
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index d4d972b2bb1..4ee9102519d 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -9,13 +9,13 @@ TEST_SRCDIR = test
 TEST_BINARY=test/test_bitcoin$(EXEEXT)
 
 JSON_TEST_FILES = \
-  test/data/script_tests.json \
-  test/data/base58_keys_valid.json \
   test/data/base58_encode_decode.json \
-  test/data/base58_keys_invalid.json \
+  test/data/key_io_valid.json \
+  test/data/key_io_invalid.json \
+  test/data/script_tests.json \
+  test/data/sighash.json \
   test/data/tx_invalid.json \
-  test/data/tx_valid.json \
-  test/data/sighash.json
+  test/data/tx_valid.json
 
 RAW_TEST_FILES =
 
@@ -45,6 +45,7 @@ BITCOIN_TESTS =\
   test/DoS_tests.cpp \
   test/getarg_tests.cpp \
   test/hash_tests.cpp \
+  test/key_io_tests.cpp \
   test/key_tests.cpp \
   test/limitedmap_tests.cpp \
   test/dbwrapper_tests.cpp \
diff --git a/src/base58.cpp b/src/base58.cpp
index 499afbe3822..982e123a1d3 100644
--- a/src/base58.cpp
+++ b/src/base58.cpp
@@ -4,20 +4,12 @@
 
 #include <base58.h>
 
-#include <bech32.h>
 #include <hash.h>
-#include <script/script.h>
 #include <uint256.h>
-#include <utilstrencodings.h>
 
-#include <boost/variant/apply_visitor.hpp>
-#include <boost/variant/static_visitor.hpp>
-
-#include <algorithm>
 #include <assert.h>
 #include <string.h>
 
-
 /** All alphanumeric characters except for "0", "I", "O", and "l" */
 static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
 
@@ -151,227 +143,3 @@ bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRe
 {
     return DecodeBase58Check(str.c_str(), vchRet);
 }
-
-CBase58Data::CBase58Data()
-{
-    vchVersion.clear();
-    vchData.clear();
-}
-
-void CBase58Data::SetData(const std::vector<unsigned char>& vchVersionIn, const void* pdata, size_t nSize)
-{
-    vchVersion = vchVersionIn;
-    vchData.resize(nSize);
-    if (!vchData.empty())
-        memcpy(vchData.data(), pdata, nSize);
-}
-
-void CBase58Data::SetData(const std::vector<unsigned char>& vchVersionIn, const unsigned char* pbegin, const unsigned char* pend)
-{
-    SetData(vchVersionIn, (void*)pbegin, pend - pbegin);
-}
-
-bool CBase58Data::SetString(const char* psz, unsigned int nVersionBytes)
-{
-    std::vector<unsigned char> vchTemp;
-    bool rc58 = DecodeBase58Check(psz, vchTemp);
-    if ((!rc58) || (vchTemp.size() < nVersionBytes)) {
-        vchData.clear();
-        vchVersion.clear();
-        return false;
-    }
-    vchVersion.assign(vchTemp.begin(), vchTemp.begin() + nVersionBytes);
-    vchData.resize(vchTemp.size() - nVersionBytes);
-    if (!vchData.empty())
-        memcpy(vchData.data(), vchTemp.data() + nVersionBytes, vchData.size());
-    memory_cleanse(vchTemp.data(), vchTemp.size());
-    return true;
-}
-
-bool CBase58Data::SetString(const std::string& str)
-{
-    return SetString(str.c_str());
-}
-
-std::string CBase58Data::ToString() const
-{
-    std::vector<unsigned char> vch = vchVersion;
-    vch.insert(vch.end(), vchData.begin(), vchData.end());
-    return EncodeBase58Check(vch);
-}
-
-int CBase58Data::CompareTo(const CBase58Data& b58) const
-{
-    if (vchVersion < b58.vchVersion)
-        return -1;
-    if (vchVersion > b58.vchVersion)
-        return 1;
-    if (vchData < b58.vchData)
-        return -1;
-    if (vchData > b58.vchData)
-        return 1;
-    return 0;
-}
-
-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};
-        ConvertBits<8, 5, true>(data, id.begin(), id.end());
-        return bech32::Encode(m_params.Bech32HRP(), data);
-    }
-
-    std::string operator()(const WitnessV0ScriptHash& id) const
-    {
-        std::vector<unsigned char> data = {0};
-        ConvertBits<8, 5, true>(data, 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};
-        ConvertBits<8, 5, true>(data, 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.
-        if (ConvertBits<5, 8, false>(data, 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
-
-void CBitcoinSecret::SetKey(const CKey& vchSecret)
-{
-    assert(vchSecret.IsValid());
-    SetData(Params().Base58Prefix(CChainParams::SECRET_KEY), vchSecret.begin(), vchSecret.size());
-    if (vchSecret.IsCompressed())
-        vchData.push_back(1);
-}
-
-CKey CBitcoinSecret::GetKey()
-{
-    CKey ret;
-    assert(vchData.size() >= 32);
-    ret.Set(vchData.begin(), vchData.begin() + 32, vchData.size() > 32 && vchData[32] == 1);
-    return ret;
-}
-
-bool CBitcoinSecret::IsValid() const
-{
-    bool fExpectedFormat = vchData.size() == 32 || (vchData.size() == 33 && vchData[32] == 1);
-    bool fCorrectVersion = vchVersion == Params().Base58Prefix(CChainParams::SECRET_KEY);
-    return fExpectedFormat && fCorrectVersion;
-}
-
-bool CBitcoinSecret::SetString(const char* pszSecret)
-{
-    return CBase58Data::SetString(pszSecret) && IsValid();
-}
-
-bool CBitcoinSecret::SetString(const std::string& strSecret)
-{
-    return SetString(strSecret.c_str());
-}
-
-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/base58.h b/src/base58.h
index 39eb4eacc2c..8f2833bec9a 100644
--- a/src/base58.h
+++ b/src/base58.h
@@ -14,12 +14,6 @@
 #ifndef BITCOIN_BASE58_H
 #define BITCOIN_BASE58_H
 
-#include <chainparams.h>
-#include <key.h>
-#include <pubkey.h>
-#include <script/standard.h>
-#include <support/allocators/zeroafterfree.h>
-
 #include <string>
 #include <vector>
 
@@ -56,95 +50,12 @@ std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn);
  * Decode a base58-encoded string (psz) that includes a checksum into a byte
  * vector (vchRet), return true if decoding is successful
  */
-inline bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet);
+bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet);
 
 /**
  * Decode a base58-encoded string (str) that includes a checksum into a byte
  * vector (vchRet), return true if decoding is successful
  */
-inline bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet);
-
-/**
- * Base class for all base58-encoded data
- */
-class CBase58Data
-{
-protected:
-    //! the version byte(s)
-    std::vector<unsigned char> vchVersion;
-
-    //! the actually encoded data
-    typedef std::vector<unsigned char, zero_after_free_allocator<unsigned char> > vector_uchar;
-    vector_uchar vchData;
-
-    CBase58Data();
-    void SetData(const std::vector<unsigned char> &vchVersionIn, const void* pdata, size_t nSize);
-    void SetData(const std::vector<unsigned char> &vchVersionIn, const unsigned char *pbegin, const unsigned char *pend);
-
-public:
-    bool SetString(const char* psz, unsigned int nVersionBytes = 1);
-    bool SetString(const std::string& str);
-    std::string ToString() const;
-    int CompareTo(const CBase58Data& b58) const;
-
-    bool operator==(const CBase58Data& b58) const { return CompareTo(b58) == 0; }
-    bool operator<=(const CBase58Data& b58) const { return CompareTo(b58) <= 0; }
-    bool operator>=(const CBase58Data& b58) const { return CompareTo(b58) >= 0; }
-    bool operator< (const CBase58Data& b58) const { return CompareTo(b58) <  0; }
-    bool operator> (const CBase58Data& b58) const { return CompareTo(b58) >  0; }
-};
-
-/**
- * A base58-encoded secret key
- */
-class CBitcoinSecret : public CBase58Data
-{
-public:
-    void SetKey(const CKey& vchSecret);
-    CKey GetKey();
-    bool IsValid() const;
-    bool SetString(const char* pszSecret);
-    bool SetString(const std::string& strSecret);
-
-    CBitcoinSecret(const CKey& vchSecret) { SetKey(vchSecret); }
-    CBitcoinSecret() {}
-};
-
-template<typename K, int Size, CChainParams::Base58Type Type> class CBitcoinExtKeyBase : public CBase58Data
-{
-public:
-    void SetKey(const K &key) {
-        unsigned char vch[Size];
-        key.Encode(vch);
-        SetData(Params().Base58Prefix(Type), vch, vch+Size);
-    }
-
-    K GetKey() {
-        K ret;
-        if (vchData.size() == Size) {
-            // If base58 encoded data does not hold an ext key, return a !IsValid() key
-            ret.Decode(vchData.data());
-        }
-        return ret;
-    }
-
-    CBitcoinExtKeyBase(const K &key) {
-        SetKey(key);
-    }
-
-    CBitcoinExtKeyBase(const std::string& strBase58c) {
-        SetString(strBase58c.c_str(), Params().Base58Prefix(Type).size());
-    }
-
-    CBitcoinExtKeyBase() {}
-};
-
-typedef CBitcoinExtKeyBase<CExtKey, BIP32_EXTKEY_SIZE, CChainParams::EXT_SECRET_KEY> CBitcoinExtKey;
-typedef CBitcoinExtKeyBase<CExtPubKey, BIP32_EXTKEY_SIZE, CChainParams::EXT_PUBLIC_KEY> CBitcoinExtPubKey;
-
-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);
+bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet);
 
 #endif // BITCOIN_BASE58_H
diff --git a/src/bitcoin-tx.cpp b/src/bitcoin-tx.cpp
index a9f7264f688..fcd836fb450 100644
--- a/src/bitcoin-tx.cpp
+++ b/src/bitcoin-tx.cpp
@@ -6,11 +6,11 @@
 #include <config/bitcoin-config.h>
 #endif
 
-#include <base58.h>
 #include <clientversion.h>
 #include <coins.h>
 #include <consensus/consensus.h>
 #include <core_io.h>
+#include <key_io.h>
 #include <keystore.h>
 #include <policy/policy.h>
 #include <policy/rbf.h>
@@ -563,12 +563,10 @@ static void MutateTxSign(CMutableTransaction& tx, const std::string& flagStr)
     for (unsigned int kidx = 0; kidx < keysObj.size(); kidx++) {
         if (!keysObj[kidx].isStr())
             throw std::runtime_error("privatekey not a std::string");
-        CBitcoinSecret vchSecret;
-        bool fGood = vchSecret.SetString(keysObj[kidx].getValStr());
-        if (!fGood)
+        CKey key = DecodeSecret(keysObj[kidx].getValStr());
+        if (!key.IsValid()) {
             throw std::runtime_error("privatekey not valid");
-
-        CKey key = vchSecret.GetKey();
+        }
         tempKeystore.AddKey(key);
     }
 
diff --git a/src/core_write.cpp b/src/core_write.cpp
index ab6918e41d8..91742b7d1b5 100644
--- a/src/core_write.cpp
+++ b/src/core_write.cpp
@@ -4,9 +4,9 @@
 
 #include <core_io.h>
 
-#include <base58.h>
 #include <consensus/consensus.h>
 #include <consensus/validation.h>
+#include <key_io.h>
 #include <script/script.h>
 #include <script/standard.h>
 #include <serialize.h>
diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index 5e9e4197441..82ae7330067 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -4,9 +4,9 @@
 
 #include <httprpc.h>
 
-#include <base58.h>
 #include <chainparams.h>
 #include <httpserver.h>
+#include <key_io.h>
 #include <rpc/protocol.h>
 #include <rpc/server.h>
 #include <random.h>
diff --git a/src/key_io.cpp b/src/key_io.cpp
new file mode 100644
index 00000000000..20df945d8de
--- /dev/null
+++ b/src/key_io.cpp
@@ -0,0 +1,223 @@
+// 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};
+        ConvertBits<8, 5, true>(data, id.begin(), id.end());
+        return bech32::Encode(m_params.Bech32HRP(), data);
+    }
+
+    std::string operator()(const WitnessV0ScriptHash& id) const
+    {
+        std::vector<unsigned char> data = {0};
+        ConvertBits<8, 5, true>(data, 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};
+        ConvertBits<8, 5, true>(data, 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.
+        if (ConvertBits<5, 8, false>(data, 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 00000000000..6fc9a8059a5
--- /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
diff --git a/src/qt/addresstablemodel.cpp b/src/qt/addresstablemodel.cpp
index ffb5bff4def..4f9a79d6545 100644
--- a/src/qt/addresstablemodel.cpp
+++ b/src/qt/addresstablemodel.cpp
@@ -7,10 +7,9 @@
 #include <qt/guiutil.h>
 #include <qt/walletmodel.h>
 
-#include <base58.h>
+#include <key_io.h>
 #include <wallet/wallet.h>
 
-
 #include <QFont>
 #include <QDebug>
 
diff --git a/src/qt/bitcoinaddressvalidator.cpp b/src/qt/bitcoinaddressvalidator.cpp
index 395ab447d2a..6a76358a783 100644
--- a/src/qt/bitcoinaddressvalidator.cpp
+++ b/src/qt/bitcoinaddressvalidator.cpp
@@ -4,7 +4,7 @@
 
 #include <qt/bitcoinaddressvalidator.h>
 
-#include <base58.h>
+#include <key_io.h>
 
 /* Base58 characters are:
      "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp
index 8d2e5619e05..b83755ab309 100644
--- a/src/qt/coincontroldialog.cpp
+++ b/src/qt/coincontroldialog.cpp
@@ -15,6 +15,7 @@
 
 #include <wallet/coincontrol.h>
 #include <init.h>
+#include <key_io.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
 #include <validation.h> // For mempool
diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp
index a46e0561b9d..7c3c68bfefa 100644
--- a/src/qt/guiutil.cpp
+++ b/src/qt/guiutil.cpp
@@ -9,7 +9,10 @@
 #include <qt/qvalidatedlineedit.h>
 #include <qt/walletmodel.h>
 
+#include <base58.h>
+#include <chainparams.h>
 #include <primitives/transaction.h>
+#include <key_io.h>
 #include <init.h>
 #include <policy/policy.h>
 #include <protocol.h>
diff --git a/src/qt/paymentrequestplus.cpp b/src/qt/paymentrequestplus.cpp
index b0ef475b356..357e98a53c6 100644
--- a/src/qt/paymentrequestplus.cpp
+++ b/src/qt/paymentrequestplus.cpp
@@ -9,6 +9,7 @@
 
 #include <qt/paymentrequestplus.h>
 
+#include <script/script.h>
 #include <util.h>
 
 #include <stdexcept>
diff --git a/src/qt/paymentrequestplus.h b/src/qt/paymentrequestplus.h
index be3923304fc..b1b60cf582d 100644
--- a/src/qt/paymentrequestplus.h
+++ b/src/qt/paymentrequestplus.h
@@ -10,7 +10,8 @@
 #include <qt/paymentrequest.pb.h>
 #pragma GCC diagnostic pop
 
-#include <base58.h>
+#include <amount.h>
+#include <script/script.h>
 
 #include <openssl/x509.h>
 
diff --git a/src/qt/paymentserver.cpp b/src/qt/paymentserver.cpp
index bc69d4f9455..8ad4fa31f18 100644
--- a/src/qt/paymentserver.cpp
+++ b/src/qt/paymentserver.cpp
@@ -8,9 +8,9 @@
 #include <qt/guiutil.h>
 #include <qt/optionsmodel.h>
 
-#include <base58.h>
 #include <chainparams.h>
 #include <policy/policy.h>
+#include <key_io.h>
 #include <ui_interface.h>
 #include <util.h>
 #include <wallet/wallet.h>
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 50d51c527d8..ec7edd48cd2 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -14,8 +14,8 @@
 #include <qt/platformstyle.h>
 #include <qt/sendcoinsentry.h>
 
-#include <base58.h>
 #include <chainparams.h>
+#include <key_io.h>
 #include <wallet/coincontrol.h>
 #include <validation.h> // mempool and minRelayTxFee
 #include <ui_interface.h>
diff --git a/src/qt/signverifymessagedialog.cpp b/src/qt/signverifymessagedialog.cpp
index 364dcd6f454..8dade8df798 100644
--- a/src/qt/signverifymessagedialog.cpp
+++ b/src/qt/signverifymessagedialog.cpp
@@ -10,8 +10,8 @@
 #include <qt/platformstyle.h>
 #include <qt/walletmodel.h>
 
-#include <base58.h>
 #include <init.h>
+#include <key_io.h>
 #include <validation.h> // For strMessageMagic
 #include <wallet/wallet.h>
 
diff --git a/src/qt/test/paymentservertests.cpp b/src/qt/test/paymentservertests.cpp
index 6e806251233..29ef4b4c9e7 100644
--- a/src/qt/test/paymentservertests.cpp
+++ b/src/qt/test/paymentservertests.cpp
@@ -8,6 +8,7 @@
 #include <qt/test/paymentrequestdata.h>
 
 #include <amount.h>
+#include <chainparams.h>
 #include <random.h>
 #include <script/script.h>
 #include <script/standard.h>
diff --git a/src/qt/test/wallettests.cpp b/src/qt/test/wallettests.cpp
index cd49292138a..5ba75cc91de 100644
--- a/src/qt/test/wallettests.cpp
+++ b/src/qt/test/wallettests.cpp
@@ -10,6 +10,7 @@
 #include <qt/transactiontablemodel.h>
 #include <qt/transactionview.h>
 #include <qt/walletmodel.h>
+#include <key_io.h>
 #include <test/test_bitcoin.h>
 #include <validation.h>
 #include <wallet/wallet.h>
diff --git a/src/qt/transactiondesc.cpp b/src/qt/transactiondesc.cpp
index 6f30e563277..c3f7ea601e4 100644
--- a/src/qt/transactiondesc.cpp
+++ b/src/qt/transactiondesc.cpp
@@ -9,8 +9,8 @@
 #include <qt/paymentserver.h>
 #include <qt/transactionrecord.h>
 
-#include <base58.h>
 #include <consensus/consensus.h>
+#include <key_io.h>
 #include <validation.h>
 #include <script/script.h>
 #include <timedata.h>
diff --git a/src/qt/transactionrecord.cpp b/src/qt/transactionrecord.cpp
index de3e885e8f9..2830149655e 100644
--- a/src/qt/transactionrecord.cpp
+++ b/src/qt/transactionrecord.cpp
@@ -4,8 +4,8 @@
 
 #include <qt/transactionrecord.h>
 
-#include <base58.h>
 #include <consensus/consensus.h>
+#include <key_io.h>
 #include <validation.h>
 #include <timedata.h>
 #include <wallet/wallet.h>
diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
index 34954a6bfa9..e7d9d276d70 100644
--- a/src/qt/walletmodel.cpp
+++ b/src/qt/walletmodel.cpp
@@ -14,8 +14,8 @@
 #include <qt/sendcoinsdialog.h>
 #include <qt/transactiontablemodel.h>
 
-#include <base58.h>
 #include <chain.h>
+#include <key_io.h>
 #include <keystore.h>
 #include <validation.h>
 #include <net.h> // for g_connman
diff --git a/src/qt/walletmodel.h b/src/qt/walletmodel.h
index 9e13de79bed..811996b98f7 100644
--- a/src/qt/walletmodel.h
+++ b/src/qt/walletmodel.h
@@ -5,6 +5,11 @@
 #ifndef BITCOIN_QT_WALLETMODEL_H
 #define BITCOIN_QT_WALLETMODEL_H
 
+#include <amount.h>
+#include <key.h>
+#include <serialize.h>
+#include <script/standard.h>
+
 #include <qt/paymentrequestplus.h>
 #include <qt/walletmodeltransaction.h>
 
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 3f3bfa0cfd9..3073a49d0db 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -3,7 +3,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
 #include <amount.h>
 #include <chain.h>
 #include <chainparams.h>
@@ -13,6 +12,7 @@
 #include <core_io.h>
 #include <init.h>
 #include <validation.h>
+#include <key_io.h>
 #include <miner.h>
 #include <net.h>
 #include <policy/fees.h>
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index f573c7dbeb4..49e865a64ac 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -3,12 +3,12 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
 #include <chain.h>
 #include <clientversion.h>
 #include <core_io.h>
 #include <crypto/ripemd160.h>
 #include <init.h>
+#include <key_io.h>
 #include <validation.h>
 #include <httpserver.h>
 #include <net.h>
@@ -224,13 +224,10 @@ UniValue signmessagewithprivkey(const JSONRPCRequest& request)
     std::string strPrivkey = request.params[0].get_str();
     std::string strMessage = request.params[1].get_str();
 
-    CBitcoinSecret vchSecret;
-    bool fGood = vchSecret.SetString(strPrivkey);
-    if (!fGood)
+    CKey key = DecodeSecret(strPrivkey);
+    if (!key.IsValid()) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key");
-    CKey key = vchSecret.GetKey();
-    if (!key.IsValid())
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key outside allowed range");
+    }
 
     CHashWriter ss(SER_GETHASH, 0);
     ss << strMessageMagic;
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 813afde4db4..8dcfb48e9ae 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -3,7 +3,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
 #include <chain.h>
 #include <coins.h>
 #include <consensus/validation.h>
@@ -12,6 +11,7 @@
 #include <keystore.h>
 #include <validation.h>
 #include <validationinterface.h>
+#include <key_io.h>
 #include <merkleblock.h>
 #include <net.h>
 #include <policy/policy.h>
@@ -896,13 +896,9 @@ UniValue signrawtransactionwithkey(const JSONRPCRequest& request)
     const UniValue& keys = request.params[1].get_array();
     for (unsigned int idx = 0; idx < keys.size(); ++idx) {
         UniValue k = keys[idx];
-        CBitcoinSecret vchSecret;
-        if (!vchSecret.SetString(k.get_str())) {
-            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key");
-        }
-        CKey key = vchSecret.GetKey();
+        CKey key = DecodeSecret(k.get_str());
         if (!key.IsValid()) {
-            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key outside allowed range");
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key");
         }
         keystore.AddKey(key);
     }
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index e5b4f6ca779..35401bf876b 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -5,9 +5,9 @@
 
 #include <rpc/server.h>
 
-#include <base58.h>
 #include <fs.h>
 #include <init.h>
+#include <key_io.h>
 #include <random.h>
 #include <sync.h>
 #include <ui_interface.h>
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index cdcb68d15f9..593962e7104 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -2,7 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
+#include <key_io.h>
 #include <keystore.h>
 #include <pubkey.h>
 #include <rpc/protocol.h>
diff --git a/src/test/base58_tests.cpp b/src/test/base58_tests.cpp
index a2d4f82695b..f90d4f90cb6 100644
--- a/src/test/base58_tests.cpp
+++ b/src/test/base58_tests.cpp
@@ -2,17 +2,10 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
-
 #include <test/data/base58_encode_decode.json.h>
-#include <test/data/base58_keys_invalid.json.h>
-#include <test/data/base58_keys_valid.json.h>
 
-#include <key.h>
-#include <script/script.h>
+#include <base58.h>
 #include <test/test_bitcoin.h>
-#include <uint256.h>
-#include <util.h>
 #include <utilstrencodings.h>
 
 #include <univalue.h>
@@ -73,135 +66,4 @@ BOOST_AUTO_TEST_CASE(base58_DecodeBase58)
     BOOST_CHECK_EQUAL_COLLECTIONS(result.begin(), result.end(), expected.begin(), expected.end());
 }
 
-// Goal: check that parsed keys match test payload
-BOOST_AUTO_TEST_CASE(base58_keys_valid_parse)
-{
-    UniValue tests = read_json(std::string(json_tests::base58_keys_valid, json_tests::base58_keys_valid + sizeof(json_tests::base58_keys_valid)));
-    CBitcoinSecret secret;
-    CTxDestination destination;
-    SelectParams(CBaseChainParams::MAIN);
-
-    for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
-        std::string strTest = test.write();
-        if (test.size() < 3) { // Allow for extra stuff (useful for comments)
-            BOOST_ERROR("Bad test: " << strTest);
-            continue;
-        }
-        std::string exp_base58string = test[0].get_str();
-        std::vector<unsigned char> exp_payload = ParseHex(test[1].get_str());
-        const UniValue &metadata = test[2].get_obj();
-        bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
-        SelectParams(find_value(metadata, "chain").get_str());
-        bool try_case_flip = find_value(metadata, "tryCaseFlip").isNull() ? false : find_value(metadata, "tryCaseFlip").get_bool();
-        if (isPrivkey) {
-            bool isCompressed = find_value(metadata, "isCompressed").get_bool();
-            // Must be valid private key
-            BOOST_CHECK_MESSAGE(secret.SetString(exp_base58string), "!SetString:"+ strTest);
-            BOOST_CHECK_MESSAGE(secret.IsValid(), "!IsValid:" + strTest);
-            CKey privkey = secret.GetKey();
-            BOOST_CHECK_MESSAGE(privkey.IsCompressed() == isCompressed, "compressed mismatch:" + strTest);
-            BOOST_CHECK_MESSAGE(privkey.size() == exp_payload.size() && std::equal(privkey.begin(), privkey.end(), exp_payload.begin()), "key mismatch:" + strTest);
-
-            // Private key must be invalid public key
-            destination = DecodeDestination(exp_base58string);
-            BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid privkey as pubkey:" + strTest);
-        } else {
-            // Must be valid public key
-            destination = DecodeDestination(exp_base58string);
-            CScript script = GetScriptForDestination(destination);
-            BOOST_CHECK_MESSAGE(IsValidDestination(destination), "!IsValid:" + strTest);
-            BOOST_CHECK_EQUAL(HexStr(script), HexStr(exp_payload));
-
-            // Try flipped case version
-            for (char& c : exp_base58string) {
-                if (c >= 'a' && c <= 'z') {
-                    c = (c - 'a') + 'A';
-                } else if (c >= 'A' && c <= 'Z') {
-                    c = (c - 'A') + 'a';
-                }
-            }
-            destination = DecodeDestination(exp_base58string);
-            BOOST_CHECK_MESSAGE(IsValidDestination(destination) == try_case_flip, "!IsValid case flipped:" + strTest);
-            if (IsValidDestination(destination)) {
-                script = GetScriptForDestination(destination);
-                BOOST_CHECK_EQUAL(HexStr(script), HexStr(exp_payload));
-            }
-
-            // Public key must be invalid private key
-            secret.SetString(exp_base58string);
-            BOOST_CHECK_MESSAGE(!secret.IsValid(), "IsValid pubkey as privkey:" + strTest);
-        }
-    }
-}
-
-// Goal: check that generated keys match test vectors
-BOOST_AUTO_TEST_CASE(base58_keys_valid_gen)
-{
-    UniValue tests = read_json(std::string(json_tests::base58_keys_valid, json_tests::base58_keys_valid + sizeof(json_tests::base58_keys_valid)));
-
-    for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
-        std::string strTest = test.write();
-        if (test.size() < 3) // Allow for extra stuff (useful for comments)
-        {
-            BOOST_ERROR("Bad test: " << strTest);
-            continue;
-        }
-        std::string exp_base58string = test[0].get_str();
-        std::vector<unsigned char> exp_payload = ParseHex(test[1].get_str());
-        const UniValue &metadata = test[2].get_obj();
-        bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
-        SelectParams(find_value(metadata, "chain").get_str());
-        if (isPrivkey) {
-            bool isCompressed = find_value(metadata, "isCompressed").get_bool();
-            CKey key;
-            key.Set(exp_payload.begin(), exp_payload.end(), isCompressed);
-            assert(key.IsValid());
-            CBitcoinSecret secret;
-            secret.SetKey(key);
-            BOOST_CHECK_MESSAGE(secret.ToString() == exp_base58string, "result mismatch: " + strTest);
-        } else {
-            CTxDestination dest;
-            CScript exp_script(exp_payload.begin(), exp_payload.end());
-            ExtractDestination(exp_script, dest);
-            std::string address = EncodeDestination(dest);
-
-            BOOST_CHECK_EQUAL(address, exp_base58string);
-        }
-    }
-
-    SelectParams(CBaseChainParams::MAIN);
-}
-
-
-// Goal: check that base58 parsing code is robust against a variety of corrupted data
-BOOST_AUTO_TEST_CASE(base58_keys_invalid)
-{
-    UniValue tests = read_json(std::string(json_tests::base58_keys_invalid, json_tests::base58_keys_invalid + sizeof(json_tests::base58_keys_invalid))); // Negative testcases
-    CBitcoinSecret secret;
-    CTxDestination destination;
-
-    for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
-        std::string strTest = test.write();
-        if (test.size() < 1) // Allow for extra stuff (useful for comments)
-        {
-            BOOST_ERROR("Bad test: " << strTest);
-            continue;
-        }
-        std::string exp_base58string = test[0].get_str();
-
-        // must be invalid as public and as private key
-        for (auto chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::REGTEST }) {
-            SelectParams(chain);
-            destination = DecodeDestination(exp_base58string);
-            BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid pubkey in mainnet:" + strTest);
-            secret.SetString(exp_base58string);
-            BOOST_CHECK_MESSAGE(!secret.IsValid(), "IsValid privkey in mainnet:" + strTest);
-        }
-    }
-}
-
-
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/bip32_tests.cpp b/src/test/bip32_tests.cpp
index 438ddc177d2..3c9ff1877dd 100644
--- a/src/test/bip32_tests.cpp
+++ b/src/test/bip32_tests.cpp
@@ -4,8 +4,8 @@
 
 #include <boost/test/unit_test.hpp>
 
-#include <base58.h>
 #include <key.h>
+#include <key_io.h>
 #include <uint256.h>
 #include <util.h>
 #include <utilstrencodings.h>
@@ -99,20 +99,12 @@ void RunTest(const TestVector &test) {
         pubkey.Encode(data);
 
         // Test private key
-        CBitcoinExtKey b58key; b58key.SetKey(key);
-        BOOST_CHECK(b58key.ToString() == derive.prv);
-
-        CBitcoinExtKey b58keyDecodeCheck(derive.prv);
-        CExtKey checkKey = b58keyDecodeCheck.GetKey();
-        assert(checkKey == key); //ensure a base58 decoded key also matches
+        BOOST_CHECK(EncodeExtKey(key) == derive.prv);
+        BOOST_CHECK(DecodeExtKey(derive.prv) == key); //ensure a base58 decoded key also matches
 
         // Test public key
-        CBitcoinExtPubKey b58pubkey; b58pubkey.SetKey(pubkey);
-        BOOST_CHECK(b58pubkey.ToString() == derive.pub);
-
-        CBitcoinExtPubKey b58PubkeyDecodeCheck(derive.pub);
-        CExtPubKey checkPubKey = b58PubkeyDecodeCheck.GetKey();
-        assert(checkPubKey == pubkey); //ensure a base58 decoded pubkey also matches
+        BOOST_CHECK(EncodeExtPubKey(pubkey) == derive.pub);
+        BOOST_CHECK(DecodeExtPubKey(derive.pub) == pubkey); //ensure a base58 decoded pubkey also matches
 
         // Derive new keys
         CExtKey keyNew;
diff --git a/src/test/bloom_tests.cpp b/src/test/bloom_tests.cpp
index af5533b109e..73c8eb5168a 100644
--- a/src/test/bloom_tests.cpp
+++ b/src/test/bloom_tests.cpp
@@ -4,9 +4,9 @@
 
 #include <bloom.h>
 
-#include <base58.h>
 #include <clientversion.h>
 #include <key.h>
+#include <key_io.h>
 #include <merkleblock.h>
 #include <primitives/block.h>
 #include <random.h>
@@ -85,10 +85,7 @@ BOOST_AUTO_TEST_CASE(bloom_create_insert_serialize_with_tweak)
 BOOST_AUTO_TEST_CASE(bloom_create_insert_key)
 {
     std::string strSecret = std::string("5Kg1gnAjaLfKiwhhPpGS3QfRg2m6awQvaj98JCZBZQ5SuS2F15C");
-    CBitcoinSecret vchSecret;
-    BOOST_CHECK(vchSecret.SetString(strSecret));
-
-    CKey key = vchSecret.GetKey();
+    CKey key = DecodeSecret(strSecret);
     CPubKey pubkey = key.GetPubKey();
     std::vector<unsigned char> vchPubKey(pubkey.begin(), pubkey.end());
 
diff --git a/src/test/data/base58_keys_invalid.json b/src/test/data/key_io_invalid.json
similarity index 100%
rename from src/test/data/base58_keys_invalid.json
rename to src/test/data/key_io_invalid.json
diff --git a/src/test/data/base58_keys_valid.json b/src/test/data/key_io_valid.json
similarity index 100%
rename from src/test/data/base58_keys_valid.json
rename to src/test/data/key_io_valid.json
diff --git a/src/test/key_io_tests.cpp b/src/test/key_io_tests.cpp
new file mode 100644
index 00000000000..1ac1e0015bf
--- /dev/null
+++ b/src/test/key_io_tests.cpp
@@ -0,0 +1,149 @@
+// Copyright (c) 2011-2016 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 <test/data/key_io_invalid.json.h>
+#include <test/data/key_io_valid.json.h>
+
+#include <key.h>
+#include <key_io.h>
+#include <script/script.h>
+#include <utilstrencodings.h>
+#include <test/test_bitcoin.h>
+
+#include <boost/test/unit_test.hpp>
+
+#include <univalue.h>
+
+extern UniValue read_json(const std::string& jsondata);
+
+BOOST_FIXTURE_TEST_SUITE(key_io_tests, BasicTestingSetup)
+
+// Goal: check that parsed keys match test payload
+BOOST_AUTO_TEST_CASE(key_io_valid_parse)
+{
+    UniValue tests = read_json(std::string(json_tests::key_io_valid, json_tests::key_io_valid + sizeof(json_tests::key_io_valid)));
+    CKey privkey;
+    CTxDestination destination;
+    SelectParams(CBaseChainParams::MAIN);
+
+    for (unsigned int idx = 0; idx < tests.size(); idx++) {
+        UniValue test = tests[idx];
+        std::string strTest = test.write();
+        if (test.size() < 3) { // Allow for extra stuff (useful for comments)
+            BOOST_ERROR("Bad test: " << strTest);
+            continue;
+        }
+        std::string exp_base58string = test[0].get_str();
+        std::vector<unsigned char> exp_payload = ParseHex(test[1].get_str());
+        const UniValue &metadata = test[2].get_obj();
+        bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
+        SelectParams(find_value(metadata, "chain").get_str());
+        bool try_case_flip = find_value(metadata, "tryCaseFlip").isNull() ? false : find_value(metadata, "tryCaseFlip").get_bool();
+        if (isPrivkey) {
+            bool isCompressed = find_value(metadata, "isCompressed").get_bool();
+            // Must be valid private key
+            privkey = DecodeSecret(exp_base58string);
+            BOOST_CHECK_MESSAGE(privkey.IsValid(), "!IsValid:" + strTest);
+            BOOST_CHECK_MESSAGE(privkey.IsCompressed() == isCompressed, "compressed mismatch:" + strTest);
+            BOOST_CHECK_MESSAGE(privkey.size() == exp_payload.size() && std::equal(privkey.begin(), privkey.end(), exp_payload.begin()), "key mismatch:" + strTest);
+
+            // Private key must be invalid public key
+            destination = DecodeDestination(exp_base58string);
+            BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid privkey as pubkey:" + strTest);
+        } else {
+            // Must be valid public key
+            destination = DecodeDestination(exp_base58string);
+            CScript script = GetScriptForDestination(destination);
+            BOOST_CHECK_MESSAGE(IsValidDestination(destination), "!IsValid:" + strTest);
+            BOOST_CHECK_EQUAL(HexStr(script), HexStr(exp_payload));
+
+            // Try flipped case version
+            for (char& c : exp_base58string) {
+                if (c >= 'a' && c <= 'z') {
+                    c = (c - 'a') + 'A';
+                } else if (c >= 'A' && c <= 'Z') {
+                    c = (c - 'A') + 'a';
+                }
+            }
+            destination = DecodeDestination(exp_base58string);
+            BOOST_CHECK_MESSAGE(IsValidDestination(destination) == try_case_flip, "!IsValid case flipped:" + strTest);
+            if (IsValidDestination(destination)) {
+                script = GetScriptForDestination(destination);
+                BOOST_CHECK_EQUAL(HexStr(script), HexStr(exp_payload));
+            }
+
+            // Public key must be invalid private key
+            privkey = DecodeSecret(exp_base58string);
+            BOOST_CHECK_MESSAGE(!privkey.IsValid(), "IsValid pubkey as privkey:" + strTest);
+        }
+    }
+}
+
+// Goal: check that generated keys match test vectors
+BOOST_AUTO_TEST_CASE(key_io_valid_gen)
+{
+    UniValue tests = read_json(std::string(json_tests::key_io_valid, json_tests::key_io_valid + sizeof(json_tests::key_io_valid)));
+
+    for (unsigned int idx = 0; idx < tests.size(); idx++) {
+        UniValue test = tests[idx];
+        std::string strTest = test.write();
+        if (test.size() < 3) // Allow for extra stuff (useful for comments)
+        {
+            BOOST_ERROR("Bad test: " << strTest);
+            continue;
+        }
+        std::string exp_base58string = test[0].get_str();
+        std::vector<unsigned char> exp_payload = ParseHex(test[1].get_str());
+        const UniValue &metadata = test[2].get_obj();
+        bool isPrivkey = find_value(metadata, "isPrivkey").get_bool();
+        SelectParams(find_value(metadata, "chain").get_str());
+        if (isPrivkey) {
+            bool isCompressed = find_value(metadata, "isCompressed").get_bool();
+            CKey key;
+            key.Set(exp_payload.begin(), exp_payload.end(), isCompressed);
+            assert(key.IsValid());
+            BOOST_CHECK_MESSAGE(EncodeSecret(key) == exp_base58string, "result mismatch: " + strTest);
+        } else {
+            CTxDestination dest;
+            CScript exp_script(exp_payload.begin(), exp_payload.end());
+            ExtractDestination(exp_script, dest);
+            std::string address = EncodeDestination(dest);
+
+            BOOST_CHECK_EQUAL(address, exp_base58string);
+        }
+    }
+
+    SelectParams(CBaseChainParams::MAIN);
+}
+
+
+// Goal: check that base58 parsing code is robust against a variety of corrupted data
+BOOST_AUTO_TEST_CASE(key_io_invalid)
+{
+    UniValue tests = read_json(std::string(json_tests::key_io_invalid, json_tests::key_io_invalid + sizeof(json_tests::key_io_invalid))); // Negative testcases
+    CKey privkey;
+    CTxDestination destination;
+
+    for (unsigned int idx = 0; idx < tests.size(); idx++) {
+        UniValue test = tests[idx];
+        std::string strTest = test.write();
+        if (test.size() < 1) // Allow for extra stuff (useful for comments)
+        {
+            BOOST_ERROR("Bad test: " << strTest);
+            continue;
+        }
+        std::string exp_base58string = test[0].get_str();
+
+        // must be invalid as public and as private key
+        for (auto chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::REGTEST }) {
+            SelectParams(chain);
+            destination = DecodeDestination(exp_base58string);
+            BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid pubkey in mainnet:" + strTest);
+            privkey = DecodeSecret(exp_base58string);
+            BOOST_CHECK_MESSAGE(!privkey.IsValid(), "IsValid privkey in mainnet:" + strTest);
+        }
+    }
+}
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/key_tests.cpp b/src/test/key_tests.cpp
index 55ee1ecf6b5..64c57f0705f 100644
--- a/src/test/key_tests.cpp
+++ b/src/test/key_tests.cpp
@@ -4,7 +4,7 @@
 
 #include <key.h>
 
-#include <base58.h>
+#include <key_io.h>
 #include <script/script.h>
 #include <uint256.h>
 #include <util.h>
@@ -32,21 +32,16 @@ BOOST_FIXTURE_TEST_SUITE(key_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(key_test1)
 {
-    CBitcoinSecret bsecret1, bsecret2, bsecret1C, bsecret2C, baddress1;
-    BOOST_CHECK( bsecret1.SetString (strSecret1));
-    BOOST_CHECK( bsecret2.SetString (strSecret2));
-    BOOST_CHECK( bsecret1C.SetString(strSecret1C));
-    BOOST_CHECK( bsecret2C.SetString(strSecret2C));
-    BOOST_CHECK(!baddress1.SetString(strAddressBad));
-
-    CKey key1  = bsecret1.GetKey();
-    BOOST_CHECK(key1.IsCompressed() == false);
-    CKey key2  = bsecret2.GetKey();
-    BOOST_CHECK(key2.IsCompressed() == false);
-    CKey key1C = bsecret1C.GetKey();
-    BOOST_CHECK(key1C.IsCompressed() == true);
-    CKey key2C = bsecret2C.GetKey();
-    BOOST_CHECK(key2C.IsCompressed() == true);
+    CKey key1  = DecodeSecret(strSecret1);
+    BOOST_CHECK(key1.IsValid() && !key1.IsCompressed());
+    CKey key2  = DecodeSecret(strSecret2);
+    BOOST_CHECK(key2.IsValid() && !key2.IsCompressed());
+    CKey key1C = DecodeSecret(strSecret1C);
+    BOOST_CHECK(key1C.IsValid() && key1C.IsCompressed());
+    CKey key2C = DecodeSecret(strSecret2C);
+    BOOST_CHECK(key2C.IsValid() && key2C.IsCompressed());
+    CKey bad_key = DecodeSecret(strAddressBad);
+    BOOST_CHECK(!bad_key.IsValid());
 
     CPubKey pubkey1  = key1. GetPubKey();
     CPubKey pubkey2  = key2. GetPubKey();
diff --git a/src/test/rpc_tests.cpp b/src/test/rpc_tests.cpp
index 108c1a063e0..892e4f2dac9 100644
--- a/src/test/rpc_tests.cpp
+++ b/src/test/rpc_tests.cpp
@@ -5,8 +5,8 @@
 #include <rpc/server.h>
 #include <rpc/client.h>
 
-#include <base58.h>
 #include <core_io.h>
+#include <key_io.h>
 #include <netbase.h>
 
 #include <test/test_bitcoin.h>
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index 930e8bbbb4e..0edc8d8d66f 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -2,8 +2,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <base58.h>
 #include <chain.h>
+#include <key_io.h>
 #include <rpc/safemode.h>
 #include <rpc/server.h>
 #include <wallet/init.h>
@@ -147,13 +147,8 @@ UniValue importprivkey(const JSONRPCRequest& request)
             throw JSONRPCError(RPC_WALLET_ERROR, "Wallet is currently rescanning. Abort existing rescan or wait.");
         }
 
-        CBitcoinSecret vchSecret;
-        bool fGood = vchSecret.SetString(strSecret);
-
-        if (!fGood) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
-
-        CKey key = vchSecret.GetKey();
-        if (!key.IsValid()) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key outside allowed range");
+        CKey key = DecodeSecret(strSecret);
+        if (!key.IsValid()) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
 
         CPubKey pubkey = key.GetPubKey();
         assert(key.VerifyPubKey(pubkey));
@@ -554,9 +549,8 @@ UniValue importwallet(const JSONRPCRequest& request)
             boost::split(vstr, line, boost::is_any_of(" "));
             if (vstr.size() < 2)
                 continue;
-            CBitcoinSecret vchSecret;
-            if (vchSecret.SetString(vstr[0])) {
-                CKey key = vchSecret.GetKey();
+            CKey key = DecodeSecret(vstr[0]);
+            if (key.IsValid()) {
                 CPubKey pubkey = key.GetPubKey();
                 assert(key.VerifyPubKey(pubkey));
                 CKeyID keyid = pubkey.GetID();
@@ -659,7 +653,7 @@ UniValue dumpprivkey(const JSONRPCRequest& request)
     if (!pwallet->GetKey(keyid, vchSecret)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Private key for address " + strAddress + " is not known");
     }
-    return CBitcoinSecret(vchSecret).ToString();
+    return EncodeSecret(vchSecret);
 }
 
 
@@ -742,10 +736,7 @@ UniValue dumpwallet(const JSONRPCRequest& request)
             CExtKey masterKey;
             masterKey.SetMaster(key.begin(), key.size());
 
-            CBitcoinExtKey b58extkey;
-            b58extkey.SetKey(masterKey);
-
-            file << "# extended private masterkey: " << b58extkey.ToString() << "\n\n";
+            file << "# extended private masterkey: " << EncodeExtKey(masterKey) << "\n\n";
         }
     }
     for (std::vector<std::pair<int64_t, CKeyID> >::const_iterator it = vKeyBirth.begin(); it != vKeyBirth.end(); it++) {
@@ -755,7 +746,7 @@ UniValue dumpwallet(const JSONRPCRequest& request)
         std::string strLabel;
         CKey key;
         if (pwallet->GetKey(keyid, key)) {
-            file << strprintf("%s %s ", CBitcoinSecret(key).ToString(), strTime);
+            file << strprintf("%s %s ", EncodeSecret(key), strTime);
             if (GetWalletAddressesForKey(pwallet, keyid, strAddr, strLabel)) {
                file << strprintf("label=%s", strLabel);
             } else if (keyid == masterKeyID) {
@@ -911,17 +902,10 @@ UniValue ProcessImport(CWallet * const pwallet, const UniValue& data, const int6
                 for (size_t i = 0; i < keys.size(); i++) {
                     const std::string& privkey = keys[i].get_str();
 
-                    CBitcoinSecret vchSecret;
-                    bool fGood = vchSecret.SetString(privkey);
-
-                    if (!fGood) {
-                        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
-                    }
-
-                    CKey key = vchSecret.GetKey();
+                    CKey key = DecodeSecret(privkey);
 
                     if (!key.IsValid()) {
-                        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key outside allowed range");
+                        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
                     }
 
                     CPubKey pubkey = key.GetPubKey();
@@ -1018,16 +1002,10 @@ UniValue ProcessImport(CWallet * const pwallet, const UniValue& data, const int6
                 const std::string& strPrivkey = keys[0].get_str();
 
                 // Checks.
-                CBitcoinSecret vchSecret;
-                bool fGood = vchSecret.SetString(strPrivkey);
+                CKey key = DecodeSecret(strPrivkey);
 
-                if (!fGood) {
-                    throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
-                }
-
-                CKey key = vchSecret.GetKey();
                 if (!key.IsValid()) {
-                    throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key outside allowed range");
+                    throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key encoding");
                 }
 
                 CPubKey pubKey = key.GetPubKey();
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 8b95c56a5fc..52b68e97ee1 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -4,12 +4,12 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <amount.h>
-#include <base58.h>
 #include <chain.h>
 #include <consensus/validation.h>
 #include <core_io.h>
 #include <httpserver.h>
 #include <validation.h>
+#include <key_io.h>
 #include <net.h>
 #include <policy/feerate.h>
 #include <policy/fees.h>
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index bb7be2df337..a014f5b2a0d 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -5,7 +5,6 @@
 
 #include <wallet/wallet.h>
 
-#include <base58.h>
 #include <checkpoints.h>
 #include <chain.h>
 #include <wallet/coincontrol.h>
@@ -14,6 +13,7 @@
 #include <fs.h>
 #include <wallet/init.h>
 #include <key.h>
+#include <key_io.h>
 #include <keystore.h>
 #include <validation.h>
 #include <net.h>
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index dd6835a06f6..c14fbd1e8ca 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -5,10 +5,10 @@
 
 #include <wallet/walletdb.h>
 
-#include <base58.h>
 #include <consensus/tx_verify.h>
 #include <consensus/validation.h>
 #include <fs.h>
+#include <key_io.h>
 #include <protocol.h>
 #include <serialize.h>
 #include <sync.h>