diff --git a/src/crypto/ripemd160.h b/src/crypto/ripemd160.h
index 687204fda..bd41f0250 100644
--- a/src/crypto/ripemd160.h
+++ b/src/crypto/ripemd160.h
@@ -14,7 +14,7 @@ class CRIPEMD160
 private:
     uint32_t s[5];
     unsigned char buf[64];
-    size_t bytes;
+    uint64_t bytes;
 
 public:
     static const size_t OUTPUT_SIZE = 20;
diff --git a/src/crypto/sha1.h b/src/crypto/sha1.h
index 7b2a21bc6..8fb20810b 100644
--- a/src/crypto/sha1.h
+++ b/src/crypto/sha1.h
@@ -14,7 +14,7 @@ class CSHA1
 private:
     uint32_t s[5];
     unsigned char buf[64];
-    size_t bytes;
+    uint64_t bytes;
 
 public:
     static const size_t OUTPUT_SIZE = 20;
diff --git a/src/crypto/sha256.h b/src/crypto/sha256.h
index 85cf33739..5b15b6a23 100644
--- a/src/crypto/sha256.h
+++ b/src/crypto/sha256.h
@@ -14,7 +14,7 @@ class CSHA256
 private:
     uint32_t s[8];
     unsigned char buf[64];
-    size_t bytes;
+    uint64_t bytes;
 
 public:
     static const size_t OUTPUT_SIZE = 32;
diff --git a/src/crypto/sha512.h b/src/crypto/sha512.h
index f1f17caf9..614681fae 100644
--- a/src/crypto/sha512.h
+++ b/src/crypto/sha512.h
@@ -14,7 +14,7 @@ class CSHA512
 private:
     uint64_t s[8];
     unsigned char buf[128];
-    size_t bytes;
+    uint64_t bytes;
 
 public:
     static const size_t OUTPUT_SIZE = 64;