diff --git a/src/crypto/ripemd160.cpp b/src/crypto/ripemd160.cpp
index a00331dcb..edee06cc3 100644
--- a/src/crypto/ripemd160.cpp
+++ b/src/crypto/ripemd160.cpp
@@ -256,7 +256,7 @@ CRIPEMD160& CRIPEMD160::Write(const unsigned char* data, size_t len)
         ripemd160::Transform(s, buf);
         bufsize = 0;
     }
-    while (end >= data + 64) {
+    while (end - data >= 64) {
         // Process full chunks directly from the source.
         ripemd160::Transform(s, data);
         bytes += 64;
diff --git a/src/crypto/sha1.cpp b/src/crypto/sha1.cpp
index 5c601c54a..3dcdcb186 100644
--- a/src/crypto/sha1.cpp
+++ b/src/crypto/sha1.cpp
@@ -163,7 +163,7 @@ CSHA1& CSHA1::Write(const unsigned char* data, size_t len)
         sha1::Transform(s, buf);
         bufsize = 0;
     }
-    while (end >= data + 64) {
+    while (end - data >= 64) {
         // Process full chunks directly from the source.
         sha1::Transform(s, data);
         bytes += 64;
diff --git a/src/crypto/sha512.cpp b/src/crypto/sha512.cpp
index bc64135ca..4e6aa363f 100644
--- a/src/crypto/sha512.cpp
+++ b/src/crypto/sha512.cpp
@@ -168,7 +168,7 @@ CSHA512& CSHA512::Write(const unsigned char* data, size_t len)
         sha512::Transform(s, buf);
         bufsize = 0;
     }
-    while (end >= data + 128) {
+    while (end - data >= 128) {
         // Process full chunks directly from the source.
         sha512::Transform(s, data);
         data += 128;