diff --git a/src/util/strencodings.h b/src/util/strencodings.h
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -177,10 +177,13 @@
  * Takes time proportional to length of first argument.
  */
 template <typename T> bool TimingResistantEqual(const T &a, const T &b) {
-    if (b.size() == 0) return a.size() == 0;
+    if (b.size() == 0) {
+        return a.size() == 0;
+    }
     size_t accumulator = a.size() ^ b.size();
-    for (size_t i = 0; i < a.size(); i++)
-        accumulator |= a[i] ^ b[i % b.size()];
+    for (size_t i = 0; i < a.size(); i++) {
+        accumulator |= size_t(a[i] ^ b[i % b.size()]);
+    }
     return accumulator == 0;
 }
 
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -95,7 +95,7 @@
         if (c == (signed char)-1) {
             break;
         }
-        uint8_t n = (c << 4);
+        auto n{uint8_t(c << 4)};
         c = HexDigit(*psz++);
         if (c == (signed char)-1) {
             break;
@@ -153,7 +153,7 @@
 }
 
 std::vector<uint8_t> DecodeBase64(const char *p, bool *pf_invalid) {
-    static const int decode64_table[256] = {
+    static const int8_t decode64_table[256] = {
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57,
@@ -178,7 +178,7 @@
         if (x == -1) {
             break;
         }
-        val.push_back(x);
+        val.push_back(uint8_t(x));
         ++p;
     }
 
@@ -234,7 +234,7 @@
 }
 
 std::vector<uint8_t> DecodeBase32(const char *p, bool *pf_invalid) {
-    static const int decode32_table[256] = {
+    static const int8_t decode32_table[256] = {
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29,
@@ -259,7 +259,7 @@
         if (x == -1) {
             break;
         }
-        val.push_back(x);
+        val.push_back(uint8_t(x));
         ++p;
     }
 
diff --git a/test/sanitizer_suppressions/ubsan b/test/sanitizer_suppressions/ubsan
--- a/test/sanitizer_suppressions/ubsan
+++ b/test/sanitizer_suppressions/ubsan
@@ -62,7 +62,6 @@
 implicit-integer-sign-change:test/streams_tests.cpp
 implicit-integer-sign-change:test/transaction_tests.cpp
 implicit-integer-sign-change:txmempool.cpp
-implicit-integer-sign-change:util/strencodings.*
 implicit-integer-sign-change:zmq/zmqpublishnotifier.cpp
 implicit-signed-integer-truncation,implicit-integer-sign-change:chain.h
 implicit-signed-integer-truncation,implicit-integer-sign-change:test/skiplist_tests.cpp