diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -13,7 +13,7 @@
 #if defined(USE_ASM)
 #include <cpuid.h>
 namespace sha256_sse4 {
-void Transform(uint32_t *s, const unsigned char *chunk, size_t blocks);
+void Transform(uint32_t *s, const uint8_t *chunk, size_t blocks);
 }
 #endif
 #endif
@@ -65,7 +65,7 @@
 
     /** Perform a number of SHA-256 transformations, processing 64-byte chunks.
      */
-    void Transform(uint32_t *s, const unsigned char *chunk, size_t blocks) {
+    void Transform(uint32_t *s, const uint8_t *chunk, size_t blocks) {
         while (blocks--) {
             uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5],
                      g = s[6], h = s[7];
@@ -215,11 +215,11 @@
 
 } // namespace sha256
 
-typedef void (*TransformType)(uint32_t *, const unsigned char *, size_t);
+typedef void (*TransformType)(uint32_t *, const uint8_t *, size_t);
 
 bool SelfTest(TransformType tr) {
-    static const unsigned char in1[65] = {0, 0x80};
-    static const unsigned char in2[129] = {
+    static const uint8_t in1[65] = {0, 0x80};
+    static const uint8_t in2[129] = {
         0,  32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,   32, 32,
         32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,   32, 32,
         32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,   32, 32,
diff --git a/src/crypto/sha256_sse4.cpp b/src/crypto/sha256_sse4.cpp
--- a/src/crypto/sha256_sse4.cpp
+++ b/src/crypto/sha256_sse4.cpp
@@ -11,7 +11,7 @@
 #if defined(__x86_64__) || defined(__amd64__)
 
 namespace sha256_sse4 {
-void Transform(uint32_t *s, const unsigned char *chunk, size_t blocks) {
+void Transform(uint32_t *s, const uint8_t *chunk, size_t blocks) {
     static const uint32_t K256 alignas(16)[] = {
         0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
         0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
diff --git a/src/netaddress.cpp b/src/netaddress.cpp
--- a/src/netaddress.cpp
+++ b/src/netaddress.cpp
@@ -16,8 +16,7 @@
 static const uint8_t pchOnionCat[] = {0xFD, 0x87, 0xD8, 0x7E, 0xEB, 0x43};
 
 // 0xFD + sha256("bitcoin")[0:5]
-static const unsigned char g_internal_prefix[] = {0xFD, 0x6B, 0x88,
-                                                  0xC0, 0x87, 0x24};
+static const uint8_t g_internal_prefix[] = {0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24};
 
 void CNetAddr::Init() {
     memset(ip, 0, sizeof(ip));