#51 crypto system

lockbox/kdf/pbkdf2.lua

@@ -0,0 +1,114 @@
+local Bit = require("lockbox.util.bit");
+local Array = require("lockbox.util.array");
+local Stream = require("lockbox.util.stream");
+local Math = require("math");
+
+local AND = Bit.band;
+local RSHIFT = Bit.rshift;
+
+local word2bytes = function(word)
+    local b0, b1, b2, b3;
+    b3 = AND(word, 0xFF); word = RSHIFT(word, 8);
+    b2 = AND(word, 0xFF); word = RSHIFT(word, 8);
+    b1 = AND(word, 0xFF); word = RSHIFT(word, 8);
+    b0 = AND(word, 0xFF);
+    return b0, b1, b2, b3;
+end
+
+local PBKDF2 = function()
+
+    local public = {};
+
+    local blockLen = 16;
+    local dKeyLen = 256;
+    local iterations = 4096;
+
+    local salt;
+    local password;
+
+
+    local PRF;
+
+    local dKey;
+
+
+    public.setBlockLen = function(len)
+        blockLen = len;
+        return public;
+    end
+
+    public.setDKeyLen = function(len)
+        dKeyLen = len
+        return public;
+    end
+
+    public.setIterations = function(iter)
+        iterations = iter;
+        return public;
+    end
+
+    public.setSalt = function(saltBytes)
+        salt = saltBytes;
+        return public;
+    end
+
+    public.setPassword = function(passwordBytes)
+        password = passwordBytes;
+        return public;
+    end
+
+    public.setPRF = function(prf)
+        PRF = prf;
+        return public;
+    end
+
+    local buildBlock = function(i)
+        local b0, b1, b2, b3 = word2bytes(i);
+        local ii = {b0, b1, b2, b3};
+        local s = Array.concat(salt, ii);
+
+        local out = {};
+
+        PRF.setKey(password);
+        for c = 1, iterations do
+            PRF.init()
+                .update(Stream.fromArray(s));
+
+            s = PRF.finish().asBytes();
+            if(c > 1) then
+                out = Array.XOR(out, s);
+            else
+                out = s;
+            end
+        end
+
+        return out;
+    end
+
+    public.finish = function()
+        local blocks = Math.ceil(dKeyLen / blockLen);
+
+        dKey = {};
+
+        for b = 1, blocks do
+            local block = buildBlock(b);
+            dKey = Array.concat(dKey, block);
+        end
+
+        if(Array.size(dKey) > dKeyLen) then dKey = Array.truncate(dKey, dKeyLen); end
+
+        return public;
+    end
+
+    public.asBytes = function()
+        return dKey;
+    end
+
+    public.asHex = function()
+        return Array.toHex(dKey);
+    end
+
+    return public;
+end
+
+return PBKDF2;