Lua

Duplicate .NET's Rfc2898DeriveBytes Functionality

See more Encryption Examples

Demonstrates how to duplicate the results produced by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class. Lua

local chilkat = require("chilkat")

-- This example assumes Chilkat Crypt2 to have been previously unlocked.
-- See Unlock Crypt2 for sample code.

-- This example demonstrates how to duplicate the results produced
-- by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class.

-- For example, here is C# code that transforms a password string into
-- bytes that can be used as a secret key for symmetric encryption (such as AES, blowfish, 3DES, etc.)
--
--     Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes("secret", System.Text.Encoding.UTF8.GetBytes("saltsalt123"), numIterations);
--     byte[] secretKeyBytes = deriveBytes.GetBytes(numBytes);

-- (The Rfc2898DeriveBytes computation is really just the PBKDF2 algorithm with SHA-1 hashing.)
-- In Chilkat, this is what we do to match...

-- First, let's get a test vector with known results.  Both Chilkat AND Microsoft should produce
-- the same results.  RFC 6070 has some PBKDF2 HMAC-SHA1 Test Vectors.  Here is one of them:

--      Input:
--        P = "passwordPASSWORDpassword" (24 octets)
--        S = "saltSALTsaltSALTsaltSALTsaltSALTsalt" (36 octets)
--        c = 4096
--        dkLen = 25
--
--      Output:
--        DK = 3d 2e ec 4f e4 1c 84 9b
--             80 c8 d8 36 62 c0 e4 4a
--             8b 29 1a 96 4c f2 f0 70
--             38                      (25 octets)
--
--

local crypt = chilkat.Crypt2.new()

local salt = "saltSALTsaltSALTsaltSALTsaltSALTsalt"
-- Given that the salt is really binary data (can be any random bunch of bytes),
-- we must pass the exact hex string representation of the salt bytes.
-- In this case, we're getting the utf-8 byte representation of our salt string,
-- which is identical to the us-ascii byte representation because there are no 8bit chars..
local saltHex = crypt:encode_string(salt, "utf-8", "hex")

-- Duplicate the test vector as shown above.
local dkHex = crypt:pbkdf2("passwordPASSWORDpassword", "utf-8", "sha1", saltHex, 4096, 25 * 8, "hex")
print(dkHex)