diff --git a/src/crypto/keccak.c b/src/crypto/keccak.c
index 090d563a2..fc6d487c2 100644
--- a/src/crypto/keccak.c
+++ b/src/crypto/keccak.c
@@ -2,6 +2,8 @@
 // 19-Nov-11  Markku-Juhani O. Saarinen <mjos@iki.fi>
 // A baseline Keccak (3rd round) implementation.
 
+#include <stdio.h>
+#include <stdlib.h>
 #include "hash-ops.h"
 #include "keccak.h"
 
@@ -73,12 +75,18 @@ void keccakf(uint64_t st[25], int rounds)
 // compute a keccak hash (md) of given byte length from "in"
 typedef uint64_t state_t[25];
 
-int keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen)
+void keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen)
 {
     state_t st;
     uint8_t temp[144];
     size_t i, rsiz, rsizw;
 
+    if (mdlen <= 0 || mdlen > 200 || sizeof(st) != 200)
+    {
+      fprintf(stderr, "Bad keccak use");
+      abort();
+    }
+
     rsiz = sizeof(state_t) == mdlen ? HASH_DATA_AREA : 200 - 2 * mdlen;
     rsizw = rsiz / 8;
     
@@ -91,6 +99,12 @@ int keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen)
     }
     
     // last block and padding
+    if (inlen >= sizeof(temp) || inlen > rsiz || rsiz - inlen + inlen + 1 >= sizeof(temp) || rsiz == 0 || rsiz - 1 >= sizeof(temp) || rsizw * 8 > sizeof(temp))
+    {
+      fprintf(stderr, "Bad keccak use");
+      abort();
+    }
+
     memcpy(temp, in, inlen);
     temp[inlen++] = 1;
     memset(temp + inlen, 0, rsiz - inlen);
@@ -102,8 +116,6 @@ int keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen)
     keccakf(st, KECCAK_ROUNDS);
 
     memcpy(md, st, mdlen);
-
-    return 0;
 }
 
 void keccak1600(const uint8_t *in, size_t inlen, uint8_t *md)
diff --git a/src/crypto/keccak.h b/src/crypto/keccak.h
index fbd8e1904..fb9d8bd04 100644
--- a/src/crypto/keccak.h
+++ b/src/crypto/keccak.h
@@ -16,7 +16,7 @@
 #endif
 
 // compute a keccak hash (md) of given byte length from "in"
-int keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen);
+void keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen);
 
 // update the state
 void keccakf(uint64_t st[25], int norounds);
diff --git a/tests/unit_tests/crypto.cpp b/tests/unit_tests/crypto.cpp
index 51e26c2bb..d9a7b8ad5 100644
--- a/tests/unit_tests/crypto.cpp
+++ b/tests/unit_tests/crypto.cpp
@@ -74,16 +74,12 @@ namespace
   {
     size_t inlen = sizeof(source);
     int mdlen = (int)sizeof(md);
-    int ret = keccak(source, inlen, md, mdlen);
+    keccak(source, inlen, md, mdlen);
 
     if (md[0] != 0x00)
     {
         return true;
     }
-    else if (!ret)
-    {
-        return true;
-    }
     else
     {
         return false;