#51 crypto system

lockbox/padding/ansix923.lua

@@ -0,0 +1,22 @@
+local ANSIX923Padding = function(blockSize, byteCount)
+
+    local paddingCount = blockSize - (byteCount % blockSize);
+    local bytesLeft = paddingCount;
+
+    local stream = function()
+        if bytesLeft > 1 then
+            bytesLeft = bytesLeft - 1;
+            return 0x00;
+        elseif bytesLeft > 0 then
+            bytesLeft = bytesLeft - 1;
+            return paddingCount;
+        else
+            return nil;
+        end
+    end
+
+    return stream;
+
+end
+
+return ANSIX923Padding;

lockbox/padding/isoiec7816.lua

@@ -0,0 +1,22 @@
+local ISOIEC7816Padding = function(blockSize, byteCount)
+
+    local paddingCount = blockSize - (byteCount % blockSize);
+    local bytesLeft = paddingCount;
+
+    local stream = function()
+        if bytesLeft == paddingCount then
+            bytesLeft = bytesLeft - 1;
+            return 0x80;
+        elseif bytesLeft > 0 then
+            bytesLeft = bytesLeft - 1;
+            return 0x00;
+        else
+            return nil;
+        end
+    end
+
+    return stream;
+
+end
+
+return ISOIEC7816Padding;

lockbox/padding/pkcs7.lua

@@ -0,0 +1,18 @@
+local PKCS7Padding = function(blockSize, byteCount)
+
+    local paddingCount = blockSize - ((byteCount -1) % blockSize) + 1;
+    local bytesLeft = paddingCount;
+
+    local stream = function()
+        if bytesLeft > 0 then
+            bytesLeft = bytesLeft - 1;
+            return paddingCount;
+        else
+            return nil;
+        end
+    end
+
+    return stream;
+end
+
+return PKCS7Padding;

lockbox/padding/zero.lua

@@ -0,0 +1,19 @@
+local ZeroPadding = function(blockSize, byteCount)
+
+    local paddingCount = blockSize - ((byteCount -1) % blockSize) + 1;
+    local bytesLeft = paddingCount;
+
+    local stream = function()
+        if bytesLeft > 0 then
+            bytesLeft = bytesLeft - 1;
+            return 0x00;
+        else
+            return nil;
+        end
+    end
+
+    return stream;
+
+end
+
+return ZeroPadding;