diff --git a/core/crypto/ed25519/crypto_hash_sha512.h b/core/crypto/ed25519/crypto_hash_sha512.h
index e5b14a66..1991c393 100644
--- a/core/crypto/ed25519/crypto_hash_sha512.h
+++ b/core/crypto/ed25519/crypto_hash_sha512.h
@@ -4,15 +4,15 @@
 #include <cryptopp/sha.h>
 
 inline void crypto_hash_sha512(unsigned char* output, const unsigned char* input,
- unsigned long long len)
+ size_t len)
 {
     CryptoPP::SHA512 hash;
     hash.CalculateDigest(output, input, len);
 }
 
 inline void crypto_hash_sha512_2(unsigned char* out,
-    const unsigned char* in1, unsigned long long len1, 
-    const unsigned char* in2, unsigned long long len2
+    const unsigned char* in1, size_t len1, 
+    const unsigned char* in2, size_t len2
 )
 {
     CryptoPP::SHA512 hash;
@@ -22,10 +22,10 @@ inline void crypto_hash_sha512_2(unsigned char* out,
 }
 
 inline void crypto_hash_sha512_3(unsigned char* out,
-    const unsigned char* in1, unsigned long long len1, 
-    const unsigned char* in2, unsigned long long len2,
-    const unsigned char* in3, unsigned long long len3
-    )
+    const unsigned char* in1, size_t len1, 
+    const unsigned char* in2, size_t len2,
+    const unsigned char* in3, size_t len3
+)
 {
     CryptoPP::SHA512 hash;
     hash.Update(in1, len1);
diff --git a/core/crypto/ed25519/ed25519_ref10.h b/core/crypto/ed25519/ed25519_ref10.h
index 1fa76c7a..681b4263 100644
--- a/core/crypto/ed25519/ed25519_ref10.h
+++ b/core/crypto/ed25519/ed25519_ref10.h
@@ -8,13 +8,13 @@ int ed25519_ref10_pubkey(unsigned char* pk, const unsigned char* sk);
 
 int ed25519_ref10_open(
     const unsigned char* sig,
-    const unsigned char* m, unsigned long long mlen,
+    const unsigned char* m, size_t mlen,
     const unsigned char*pk
 );
 
 int ed25519_ref10_sign(
     unsigned char* sig,
-    const unsigned char* m, unsigned long long mlen,
+    const unsigned char* m, size_t mlen,
     const unsigned char* sk, const unsigned char* pk
 );
 
diff --git a/core/crypto/ed25519/ge_scalarmult_base.cpp b/core/crypto/ed25519/ge_scalarmult_base.cpp
index 421e4fa0..a55c3c46 100644
--- a/core/crypto/ed25519/ge_scalarmult_base.cpp
+++ b/core/crypto/ed25519/ge_scalarmult_base.cpp
@@ -14,7 +14,7 @@ static unsigned char equal(signed char b,signed char c)
 
 static unsigned char negative(signed char b)
 {
-  unsigned long long x = b; /* 18446744073709551361..18446744073709551615: yes; 0..255: no */
+  uint64_t x = b; /* 18446744073709551361..18446744073709551615: yes; 0..255: no */
   x >>= 63; /* 1: yes; 0: no */
   return x;
 }
diff --git a/core/crypto/ed25519/open.cpp b/core/crypto/ed25519/open.cpp
index 0264f893..2ad0b156 100644
--- a/core/crypto/ed25519/open.cpp
+++ b/core/crypto/ed25519/open.cpp
@@ -7,7 +7,7 @@
 
 int crypto_sign_open(
   const unsigned char* sig,
-  const unsigned char* m, unsigned long long mlen,
+  const unsigned char* m, size_t mlen,
   const unsigned char* pk
 )
 {
diff --git a/core/crypto/ed25519/sign.cpp b/core/crypto/ed25519/sign.cpp
index 06a65ce1..68ab0eab 100644
--- a/core/crypto/ed25519/sign.cpp
+++ b/core/crypto/ed25519/sign.cpp
@@ -6,7 +6,7 @@
 
 int crypto_sign(
   unsigned char *sig,
-  const unsigned char* m, unsigned long long mlen,
+  const unsigned char* m, size_t mlen,
   const unsigned char* sk, const unsigned char* pk
 )
 {