labo2-fsharp/labo2-fsharp/Crypto.fs

   1 module Labo2.Crypto
   2
   3 open System.Security.Cryptography
   4 open System.IO
   5
   6 type Key = string
   7 type Data = byte[]
   8
   9 let rsaKeySize = 2048
  10
  11 let generate256Key : Key =
  12     null
  13
  14 /// Generate a new RSA key pair: (public * private).
  15 let generateRSAKeysPair : Key * Key =
  16     use rsa = new RSACryptoServiceProvider (rsaKeySize)
  17     try
  18         rsa.ToXmlString false, rsa.ToXmlString true
  19     finally
  20         rsa.PersistKeyInCsp <- false
  21
  22 let encryptRSA (publicKey : Key) (plaindata : Data) : Data =
  23     use rsa = new RSACryptoServiceProvider (rsaKeySize)
  24     try
  25         rsa.FromXmlString publicKey
  26         rsa.Encrypt (plaindata, false) // Uses PKCS#1 v1.5 padding.
  27     finally
  28         rsa.PersistKeyInCsp <- false
  29
  30 let decryptRSA (privateKey : Key) (cipherdata : Data) : Data =
  31     use rsa = new RSACryptoServiceProvider (rsaKeySize)
  32     try
  33         rsa.FromXmlString privateKey
  34         rsa.Decrypt (cipherdata, false) // Uses PKCS#1 v1.5 padding.
  35     finally
  36         rsa.PersistKeyInCsp <- false
  37
  38 /// Produces a signature from a given hash.
  39 let signRSA (privKey : Key) (sha256 : Data) : Data =
  40     use rsa = new RSACryptoServiceProvider (rsaKeySize)
  41     try
  42         rsa.FromXmlString privKey
  43         rsa.SignHash (sha256, CryptoConfig.MapNameToOID "SHA256")
  44     finally
  45         rsa.PersistKeyInCsp <- false
  46
  47 /// Verify a signature against a given hash.
  48 let verifySignRSA (pubKey : Key) (sha256 : Data) (signature : Data) : bool =
  49     use rsa = new RSACryptoServiceProvider (rsaKeySize)
  50     try
  51         rsa.FromXmlString pubKey
  52         rsa.VerifyHash (sha256, CryptoConfig.MapNameToOID "SHA256", signature)
  53     finally
  54         rsa.PersistKeyInCsp <- false
  55
  56 let decryptAES (key : Key) (inputStream : Stream) (outputStream : Stream) =
  57     ()
  58
  59 open System.Text
  60
  61 let testRSA = lazy (
  62         let kpub, kpriv = generateRSAKeysPair
  63         let plaintext = "Hello, World!"
  64         printfn "plaintext: %A" plaintext
  65         let cipherdata = encryptRSA kpub (Encoding.UTF8.GetBytes plaintext)
  66         printfn "cipherdata: (size: %A) %A" cipherdata.Length cipherdata
  67         let decryptedData = decryptRSA kpriv cipherdata
  68         let decryptedText = Encoding.UTF8.GetString decryptedData
  69         printfn "decryptedtext: %A" decryptedText
  70         assert (plaintext = decryptedText)
  71         printfn "testRSA OK"
  72     )
  73
  74 let testRSASignature = lazy (
  75         let kpub, kpriv = generateRSAKeysPair
  76         let plaintext = "Hello, World!"
  77         let sha256 = new SHA256Managed ()
  78         let signature = signRSA kpriv (sha256.ComputeHash (Encoding.UTF8.GetBytes plaintext))
  79         assert verifySignRSA kpub (sha256.ComputeHash (Encoding.UTF8.GetBytes plaintext)) signature
  80         assert not (verifySignRSA kpub (sha256.ComputeHash (Encoding.UTF8.GetBytes "Hello!")) signature)
  81         printfn "testRSASignature OK"
  82     )