diff --git a/src/crypto/ripemd160.cpp b/src/crypto/ripemd160.cpp
index c5e6e2d69..24bd318d4 100644
--- a/src/crypto/ripemd160.cpp
+++ b/src/crypto/ripemd160.cpp
@@ -184,7 +184,7 @@ CRIPEMD160& CRIPEMD160::Write(const unsigned char *data, size_t len) {
     return *this;
 }
 
-void CRIPEMD160::Finalize(unsigned char *hash) {
+void CRIPEMD160::Finalize(unsigned char hash[OUTPUT_SIZE]) {
     static const unsigned char pad[64] = {0x80};
     unsigned char sizedesc[8];
     WriteLE64(sizedesc, bytes << 3);
diff --git a/src/crypto/ripemd160.h b/src/crypto/ripemd160.h
index cab1d0bb4..44bd4879a 100644
--- a/src/crypto/ripemd160.h
+++ b/src/crypto/ripemd160.h
@@ -16,9 +16,11 @@ private:
     size_t bytes;
 
 public:
+    static const size_t OUTPUT_SIZE = 20;
+
     CRIPEMD160();
     CRIPEMD160& Write(const unsigned char *data, size_t len);
-    void Finalize(unsigned char *hash);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
     CRIPEMD160& Reset();
 };
 
diff --git a/src/crypto/sha1.cpp b/src/crypto/sha1.cpp
index e0f32b7d1..304401a50 100644
--- a/src/crypto/sha1.cpp
+++ b/src/crypto/sha1.cpp
@@ -172,7 +172,7 @@ CSHA1& CSHA1::Write(const unsigned char *data, size_t len) {
     return *this;
 }
 
-void CSHA1::Finalize(unsigned char *hash) {
+void CSHA1::Finalize(unsigned char hash[OUTPUT_SIZE]) {
     static const unsigned char pad[64] = {0x80};
     unsigned char sizedesc[8];
     WriteBE64(sizedesc, bytes << 3);
diff --git a/src/crypto/sha1.h b/src/crypto/sha1.h
index 6efde78a5..b16f2c88c 100644
--- a/src/crypto/sha1.h
+++ b/src/crypto/sha1.h
@@ -16,9 +16,11 @@ private:
     size_t bytes;
 
 public:
+    static const size_t OUTPUT_SIZE = 20;
+
     CSHA1();
     CSHA1& Write(const unsigned char *data, size_t len);
-    void Finalize(unsigned char *hash);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
     CSHA1& Reset();
 };
 
diff --git a/src/crypto/sha2.cpp b/src/crypto/sha2.cpp
index 77f35f38d..99a251cb1 100644
--- a/src/crypto/sha2.cpp
+++ b/src/crypto/sha2.cpp
@@ -295,7 +295,7 @@ CSHA256& CSHA256::Write(const unsigned char *data, size_t len) {
     return *this;
 }
 
-void CSHA256::Finalize(unsigned char *hash) {
+void CSHA256::Finalize(unsigned char hash[OUTPUT_SIZE]) {
     static const unsigned char pad[64] = {0x80};
     unsigned char sizedesc[8];
     WriteBE64(sizedesc, bytes << 3);
@@ -348,7 +348,7 @@ CSHA512& CSHA512::Write(const unsigned char *data, size_t len) {
     return *this;
 }
 
-void CSHA512::Finalize(unsigned char *hash) {
+void CSHA512::Finalize(unsigned char hash[OUTPUT_SIZE]) {
     static const unsigned char pad[128] = {0x80};
     unsigned char sizedesc[16] = {0x00};
     WriteBE64(sizedesc+8, bytes << 3);
@@ -391,7 +391,7 @@ CHMAC_SHA512::CHMAC_SHA512(const unsigned char *key, size_t keylen) {
     inner.Write(rkey, 128);
 }
 
-void CHMAC_SHA512::Finalize(unsigned char *hash) {
+void CHMAC_SHA512::Finalize(unsigned char hash[OUTPUT_SIZE]) {
     unsigned char temp[64];
     inner.Finalize(temp);
     outer.Write(temp, 64).Finalize(hash);
diff --git a/src/crypto/sha2.h b/src/crypto/sha2.h
index 001bfc647..088d5e194 100644
--- a/src/crypto/sha2.h
+++ b/src/crypto/sha2.h
@@ -16,9 +16,11 @@ private:
     size_t bytes;
 
 public:
+    static const size_t OUTPUT_SIZE = 32;
+
     CSHA256();
     CSHA256& Write(const unsigned char *data, size_t len);
-    void Finalize(unsigned char *hash);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
     CSHA256& Reset();
 };
 
@@ -30,9 +32,11 @@ private:
     size_t bytes;
 
 public:
+    static const size_t OUTPUT_SIZE = 64;
+
     CSHA512();
     CSHA512& Write(const unsigned char *data, size_t len);
-    void Finalize(unsigned char *hash);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
     CSHA512& Reset();
 };
 
@@ -43,12 +47,14 @@ private:
     CSHA512 inner;
 
 public:
+    static const size_t OUTPUT_SIZE = 64;
+
     CHMAC_SHA512(const unsigned char *key, size_t keylen);
     CHMAC_SHA512& Write(const unsigned char *data, size_t len) {
         inner.Write(data, len);
         return *this;
     }
-    void Finalize(unsigned char *hash);
+    void Finalize(unsigned char hash[OUTPUT_SIZE]);
 };
 
 #endif
diff --git a/src/hash.h b/src/hash.h
index 39d42eefe..f2a0ebfe1 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -19,10 +19,12 @@ class CHash256 {
 private:
     CSHA256 sha;
 public:
-    void Finalize(unsigned char *hash) {
-        unsigned char buf[32];
+    static const size_t OUTPUT_SIZE = CSHA256::OUTPUT_SIZE;
+
+    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
+        unsigned char buf[sha.OUTPUT_SIZE];
         sha.Finalize(buf);
-        sha.Reset().Write(buf, 32).Finalize(hash);
+        sha.Reset().Write(buf, sha.OUTPUT_SIZE).Finalize(hash);
     }
 
     CHash256& Write(const unsigned char *data, size_t len) {
@@ -41,10 +43,12 @@ class CHash160 {
 private:
     CSHA256 sha;
 public:
-    void Finalize(unsigned char *hash) {
-        unsigned char buf[32];
+    static const size_t OUTPUT_SIZE = CRIPEMD160::OUTPUT_SIZE;
+
+    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
+        unsigned char buf[sha.OUTPUT_SIZE];
         sha.Finalize(buf);
-        CRIPEMD160().Write(buf, 32).Finalize(hash);
+        CRIPEMD160().Write(buf, sha.OUTPUT_SIZE).Finalize(hash);
     }
 
     CHash160& Write(const unsigned char *data, size_t len) {
diff --git a/src/test/crypto_tests.cpp b/src/test/crypto_tests.cpp
index d425f082c..7bd98fa38 100644
--- a/src/test/crypto_tests.cpp
+++ b/src/test/crypto_tests.cpp
@@ -16,6 +16,7 @@ BOOST_AUTO_TEST_SUITE(crypto_tests)
 template<typename Hasher, typename In, typename Out>
 void TestVector(const Hasher &h, const In &in, const Out &out) {
     Out hash;
+    BOOST_CHECK(out.size() == h.OUTPUT_SIZE);
     hash.resize(out.size());
     {
         // Test that writing the whole input string at once works.