1 files changed, 35 insertions, 0 deletions
diff --git a/pbkdf2.lua b/pbkdf2.lua
new file mode 100644
index 0000000..819ba9f
--- /dev/null
+++ b/pbkdf2.lua
@@ -0,0 +1,35 @@
+local rand = require 'openssl.rand'
+local hmac = require 'openssl.hmac'
+
+local function xor(a, b)
+	local x = {}
+	for i = 1, #b do
+		x[i] = string.char(a:byte(i) ~ b:byte(i))
+	end
+	return table.concat(x)
+end
+
+local function prf(algo, password, salt, iter)
+	local k
+	local prev = salt
+	for i = 1, iter do
+		local h = hmac.new(password, algo)
+		local sum = h:final(prev)
+		k = k and xor(k, sum) or sum
+		prev = sum
+	end
+	return k
+end
+
+return function(password, salt, algo, iter, blocks)
+	local salt = salt or rand.bytes(256)
+	local algo = algo or 'sha3-512'
+	local iter = iter or 10000
+	local blocks = blocks or 1
+
+	local dk = ""
+	for i = 1, blocks do
+		dk = dk .. prf(algo, password, salt..(('>I4'):pack(i)), iter)
+	end
+	return dk, salt, algo, iter, blocks
+end