diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
index 4e23567a71..84d806d65a 100644
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -91,7 +91,7 @@ std::vector<unsigned char> ParseHex(const char* psz)
         signed char c = HexDigit(*psz++);
         if (c == (signed char)-1)
             break;
-        unsigned char n = (c << 4);
+        auto n{uint8_t(c << 4)};
         c = HexDigit(*psz++);
         if (c == (signed char)-1)
             break;
@@ -145,8 +145,7 @@ std::string EncodeBase64(const std::string& str)
 
 std::vector<unsigned char> 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, 58, 59, 60, 61, -1, -1,
@@ -168,7 +167,7 @@ std::vector<unsigned char> DecodeBase64(const char* p, bool* pf_invalid)
     while (*p != 0) {
         int x = decode64_table[(unsigned char)*p];
         if (x == -1) break;
-        val.push_back(x);
+        val.push_back(uint8_t(x));
         ++p;
     }
 
@@ -224,8 +223,7 @@ std::string EncodeBase32(const std::string& str, bool pad)
 
 std::vector<unsigned char> 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, 30, 31, -1, -1, -1, -1,
@@ -247,7 +245,7 @@ std::vector<unsigned char> DecodeBase32(const char* p, bool* pf_invalid)
     while (*p != 0) {
         int x = decode32_table[(unsigned char)*p];
         if (x == -1) break;
-        val.push_back(x);
+        val.push_back(uint8_t(x));
         ++p;
     }
 
@@ -540,14 +538,14 @@ std::string HexStr(const Span<const uint8_t> s)
 std::string ToLower(const std::string& str)
 {
     std::string r;
-    for (auto ch : str) r += ToLower((unsigned char)ch);
+    for (auto ch : str) r += ToLower(ch);
     return r;
 }
 
 std::string ToUpper(const std::string& str)
 {
     std::string r;
-    for (auto ch : str) r += ToUpper((unsigned char)ch);
+    for (auto ch : str) r += ToUpper(ch);
     return r;
 }
 
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
index 19e9f966ab..427f3e2651 100644
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -212,7 +212,7 @@ bool TimingResistantEqual(const T& a, const T& b)
     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()];
+        accumulator |= size_t(a[i] ^ b[i%b.size()]);
     return accumulator == 0;
 }
 
diff --git a/test/sanitizer_suppressions/ubsan b/test/sanitizer_suppressions/ubsan
index b181d1e97f..762b40f00d 100644
--- a/test/sanitizer_suppressions/ubsan
+++ b/test/sanitizer_suppressions/ubsan
@@ -59,7 +59,6 @@ implicit-integer-sign-change:test/sighash_tests.cpp
 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:validation.cpp
 implicit-integer-sign-change:zmq/zmqpublishnotifier.cpp
 implicit-signed-integer-truncation,implicit-integer-sign-change:chain.h