diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -27,11 +27,11 @@
 }
 
 namespace sha256d64_shani {
-void Transform_2way(unsigned char *out, const unsigned char *in);
+void Transform_2way(uint8_t *out, const uint8_t *in);
 }
 
 namespace sha256_shani {
-void Transform(uint32_t *s, const unsigned char *chunk, size_t blocks);
+void Transform(uint32_t *s, const uint8_t *chunk, size_t blocks);
 }
 
 // Internal implementation code.
@@ -700,7 +700,7 @@
 
     // Test TransformD64_2way, if available.
     if (TransformD64_2way) {
-        unsigned char out[64];
+        uint8_t out[64];
         TransformD64_2way(out, data + 1);
         if (!std::equal(out, out + 64, result_d64)) return false;
     }
diff --git a/src/crypto/sha256_shani.cpp b/src/crypto/sha256_shani.cpp
--- a/src/crypto/sha256_shani.cpp
+++ b/src/crypto/sha256_shani.cpp
@@ -70,17 +70,17 @@
     s1 = _mm_alignr_epi8(t2, t1, 0x08);
 }
 
-__m128i inline __attribute__((always_inline)) Load(const unsigned char *in) {
+__m128i inline __attribute__((always_inline)) Load(const uint8_t *in) {
     return _mm_shuffle_epi8(_mm_loadu_si128((const __m128i *)in), MASK);
 }
 
-inline void __attribute__((always_inline)) Save(unsigned char *out, __m128i s) {
+inline void __attribute__((always_inline)) Save(uint8_t *out, __m128i s) {
     _mm_storeu_si128((__m128i *)out, _mm_shuffle_epi8(s, MASK));
 }
 }
 
 namespace sha256_shani {
-void Transform(uint32_t *s, const unsigned char *chunk, size_t blocks) {
+void Transform(uint32_t *s, const uint8_t *chunk, size_t blocks) {
     __m128i m0, m1, m2, m3, s0, s1, so0, so1;
 
     /* Load state */
@@ -145,7 +145,7 @@
 
 namespace sha256d64_shani {
 
-void Transform_2way(unsigned char *out, const unsigned char *in) {
+void Transform_2way(uint8_t *out, const uint8_t *in) {
     __m128i am0, am1, am2, am3, as0, as1, aso0, aso1;
     __m128i bm0, bm1, bm2, bm3, bs0, bs1, bso0, bso1;
 
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -148,7 +148,7 @@
                           bool include_addresses = false) const {
         // Always present: script type and redeemscript
         txnouttype which_type;
-        std::vector<std::vector<unsigned char>> solutions_data;
+        std::vector<std::vector<uint8_t>> solutions_data;
         Solver(subscript, which_type, solutions_data);
         obj.pushKV("script", GetTxnOutputType(which_type));
         obj.pushKV("hex", HexStr(subscript.begin(), subscript.end()));
diff --git a/src/utilstrencodings.h b/src/utilstrencodings.h
--- a/src/utilstrencodings.h
+++ b/src/utilstrencodings.h
@@ -213,7 +213,7 @@
  * @return          the lowercase equivalent of c; or the argument
  *                  if no conversion is possible.
  */
-constexpr unsigned char ToLower(unsigned char c) {
+constexpr uint8_t ToLower(uint8_t c) {
     return (c >= 'A' && c <= 'Z' ? (c - 'A') + 'a' : c);
 }
 
@@ -233,7 +233,7 @@
  * @return          the uppercase equivalent of c; or the argument
  *                  if no conversion is possible.
  */
-constexpr unsigned char ToUpper(unsigned char c) {
+constexpr uint8_t ToUpper(uint8_t c) {
     return (c >= 'a' && c <= 'z' ? (c - 'a') + 'A' : c);
 }
 
diff --git a/src/utilstrencodings.cpp b/src/utilstrencodings.cpp
--- a/src/utilstrencodings.cpp
+++ b/src/utilstrencodings.cpp
@@ -803,7 +803,7 @@
 
 void Downcase(std::string &str) {
     std::transform(str.begin(), str.end(), str.begin(),
-                   [](unsigned char c) { return ToLower(c); });
+                   [](uint8_t c) { return ToLower(c); });
 }
 
 std::string Capitalize(std::string str) {
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -671,7 +671,7 @@
                 }
                 nTimeBegin = std::min(nTimeBegin, nTime);
             } else if (IsHex(vstr[0])) {
-                std::vector<unsigned char> vData(ParseHex(vstr[0]));
+                std::vector<uint8_t> vData(ParseHex(vstr[0]));
                 CScript script = CScript(vData.begin(), vData.end());
                 if (pwallet->HaveCScript(script)) {
                     LogPrintf(