diff --git a/libi2pd/Crypto.cpp b/libi2pd/Crypto.cpp
index 567ae574..469dac26 100644
--- a/libi2pd/Crypto.cpp
+++ b/libi2pd/Crypto.cpp
@@ -188,10 +188,10 @@ namespace crypto
 	static void DestroyElggTable (BIGNUM * table[][255], int len)
 	{
 		for (int i = 0; i < len; i++)
-			for (int j = 0; j < 255; j++)
+			for (auto & j : table[i])
 			{
-				BN_free (table[i][j]);
-				table[i][j] = nullptr;
+				BN_free (j);
+				j = nullptr;
 			}
 		BN_MONT_CTX_free (g_MontCtx);
 	}
diff --git a/libi2pd/Ed25519.cpp b/libi2pd/Ed25519.cpp
index 69fec4e8..93d08d1e 100644
--- a/libi2pd/Ed25519.cpp
+++ b/libi2pd/Ed25519.cpp
@@ -54,14 +54,14 @@ namespace crypto
 
 		// precalculate Bi256 table
 		Bi256Carry = { Bx, By };  // B
-		for (int i = 0; i < 32; i++)
+		for (auto & i : Bi256)
 		{
-			Bi256[i][0] = Bi256Carry; // first point
+			i[0] = Bi256Carry; // first point
 			for (int j = 1; j < 128; j++)
-				Bi256[i][j] = Sum (Bi256[i][j-1], Bi256[i][0], ctx); // (256+j+1)^i*B
-			Bi256Carry = Bi256[i][127];
+				i[j] = Sum (i[j-1], i[0], ctx); // (256+j+1)^i*B
+			Bi256Carry = i[127];
 			for (int j = 0; j < 128; j++) // add first point 128 more times
-				Bi256Carry = Sum (Bi256Carry, Bi256[i][0], ctx);
+				Bi256Carry = Sum (Bi256Carry, i[0], ctx);
 		}
 
 		BN_CTX_free (ctx);
diff --git a/libi2pd/Gost.cpp b/libi2pd/Gost.cpp
index c401f8be..d1202b2a 100644
--- a/libi2pd/Gost.cpp
+++ b/libi2pd/Gost.cpp
@@ -838,10 +838,10 @@ namespace crypto
 		{
 			GOST3411Block k = *this;
 			GOST3411Block res = k^m;
-			for (int i = 0; i < 12; i++)
+			for (const auto & i : C_)
 			{
 				res.F ();
-				k = k^C_[i];
+				k = k^i;
 				k.F ();
 				res = k^res;
 			}
diff --git a/libi2pd/TunnelGateway.cpp b/libi2pd/TunnelGateway.cpp
index 7d0069a9..e2c6ff5b 100644
--- a/libi2pd/TunnelGateway.cpp
+++ b/libi2pd/TunnelGateway.cpp
@@ -14,8 +14,8 @@ namespace tunnel
 		m_CurrentTunnelDataMsg (nullptr), m_RemainingSize (0)
 	{
 		RAND_bytes (m_NonZeroRandomBuffer, TUNNEL_DATA_MAX_PAYLOAD_SIZE);
-		for (size_t i = 0; i < TUNNEL_DATA_MAX_PAYLOAD_SIZE; i++)
-			if (!m_NonZeroRandomBuffer[i]) m_NonZeroRandomBuffer[i] = 1;
+		for (unsigned char & i : m_NonZeroRandomBuffer)
+			if (!i) i = 1;
 	}
 
 	TunnelGatewayBuffer::~TunnelGatewayBuffer ()