diff --git a/src/Makefile.test.include b/src/Makefile.test.include
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -86,6 +86,7 @@
   test/scriptflags.h \
   test/scriptnum_tests.cpp \
   test/serialize_tests.cpp \
+  test/sigencoding_tests.cpp \
   test/sighash_tests.cpp \
   test/sighashtype_tests.cpp \
   test/sigopcount_tests.cpp \
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -100,6 +100,7 @@
 	scriptflags.cpp
 	scriptnum_tests.cpp
 	serialize_tests.cpp
+	sigencoding_tests.cpp
 	sighash_tests.cpp
 	sighashtype_tests.cpp
 	sigopcount_tests.cpp
diff --git a/src/test/script_P2SH_tests.cpp b/src/test/script_P2SH_tests.cpp
--- a/src/test/script_P2SH_tests.cpp
+++ b/src/test/script_P2SH_tests.cpp
@@ -317,8 +317,9 @@
         key[i].MakeNewKey(true);
         keystore.AddKey(key[i]);
     }
-    for (int i = 0; i < 3; i++)
+    for (int i = 0; i < 3; i++) {
         keys.push_back(key[i].GetPubKey());
+    }
 
     CMutableTransaction txFrom;
     txFrom.vout.resize(7);
@@ -356,8 +357,9 @@
     // vout[4] is max sigops:
     CScript fifteenSigops;
     fifteenSigops << OP_1;
-    for (unsigned i = 0; i < MAX_P2SH_SIGOPS; i++)
+    for (unsigned i = 0; i < MAX_P2SH_SIGOPS; i++) {
         fifteenSigops << ToByteVector(key[i % 3].GetPubKey());
+    }
     fifteenSigops << OP_15 << OP_CHECKMULTISIG;
     keystore.AddCScript(fifteenSigops);
     txFrom.vout[4].scriptPubKey =
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -211,7 +211,6 @@
     CPubKey pubkey2, pubkey2C;
 
     KeyData() {
-
         key0.Set(vchKey0, vchKey0 + 32, false);
         key0C.Set(vchKey0, vchKey0 + 32, true);
         pubkey0 = key0.GetPubKey();
diff --git a/src/test/sigencoding_tests.cpp b/src/test/sigencoding_tests.cpp
new file mode 100644
--- /dev/null
+++ b/src/test/sigencoding_tests.cpp
@@ -0,0 +1,150 @@
+// Copyright (c) 2018 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "test/test_bitcoin.h"
+
+#include "script/script_flags.h"
+#include "script/sigencoding.h"
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(sigencoding_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(checkpubkeyencoding_test) {
+    valtype compressedKey0{0x02, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+                           0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12,
+                           0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+                           0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0};
+    valtype compressedKey1{0x03, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+                           0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56,
+                           0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78,
+                           0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff};
+    valtype fullKey{0x04, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12,
+                    0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56,
+                    0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+                    0xbc, 0xde, 0xf0, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12,
+                    0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56,
+                    0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+                    0xbc, 0xde, 0xf0, 0x0f, 0xff};
+
+    std::vector<valtype> invalidKeys{
+        // Degenerate keys.
+        {},
+        {0x00},
+        {0x42},
+        {0xff},
+        // Invalid first byte 0x00.
+        {0x00, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0x00, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Invalid first byte 0x01.
+        {0x01, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0x00, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Invalid first byte 0x05.
+        {0x05, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0x05, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Invalid first byte 0xff.
+        {0xff, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0xff, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Compressed key too short.
+        {0x02, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0x03, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78,
+         0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde,
+         0xf0, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Compressed key too long.
+        {0x02, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56,
+         0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0xab, 0xba, 0x9a,
+         0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+        {0x03, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0xab,
+         0xba, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Compressed key, full key size.
+        {0x02, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        {0x03, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Full key, too short.
+        {0x04, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12,
+         0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Full key, too long.
+        {0x04, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34,
+         0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
+         0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0,
+         0x56, 0x78, 0xab, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78,
+         0x9a, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xde,
+         0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x0f, 0xff},
+        // Full key, compressed key size.
+        {0x04, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56,
+         0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0xab, 0xba, 0x9a,
+         0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0},
+    };
+
+    // If we add many more flags, this loop can get too expensive, but we can
+    // rewrite in the future to randomly pick a set of flags to evaluate.
+    for (uint32_t flags = 0; flags < (1U << 17); flags++) {
+        ScriptError err = SCRIPT_ERR_OK;
+
+        // Compressed pubkeys are always valid.
+        BOOST_CHECK(CheckPubKeyEncoding(compressedKey0, flags, &err));
+        BOOST_CHECK(CheckPubKeyEncoding(compressedKey1, flags, &err));
+
+        // If SCRIPT_VERIFY_COMPRESSED_PUBKEYTYPE is specified, full key are
+        // disabled.
+        bool allowFullKey = (flags & SCRIPT_VERIFY_COMPRESSED_PUBKEYTYPE) == 0;
+        BOOST_CHECK_EQUAL(CheckPubKeyEncoding(fullKey, flags, &err),
+                          allowFullKey);
+
+        // If SCRIPT_VERIFY_STRICTENC or SCRIPT_VERIFY_COMPRESSED_PUBKEYTYPE is
+        // specified, we rule out invalid keys.
+        bool allowInvalidKeys =
+            allowFullKey && (flags & SCRIPT_VERIFY_STRICTENC) == 0;
+        for (const valtype &key : invalidKeys) {
+            BOOST_CHECK_EQUAL(CheckPubKeyEncoding(key, flags, &err),
+                              allowInvalidKeys);
+        }
+    }
+}
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp
--- a/src/test/txvalidationcache_tests.cpp
+++ b/src/test/txvalidationcache_tests.cpp
@@ -107,7 +107,7 @@
     PrecomputedTransactionData txdata(tx);
     // If we add many more flags, this loop can get too expensive, but we can
     // rewrite in the future to randomly pick a set of flags to evaluate.
-    for (size_t test_flags = 0; test_flags < (1U << 17); test_flags += 1) {
+    for (uint32_t test_flags = 0; test_flags < (1U << 17); test_flags += 1) {
         CValidationState state;
         // Make sure the mandatory flags are enabled.
         test_flags |= MANDATORY_SCRIPT_VERIFY_FLAGS;