labo2-fsharp/CryptoFile/API.fs

   1 namespace CryptoFile
   2 open System.IO
   3
   4 type internal Metadata (d: (string * string) list) =
   5     new (stream : Stream, size: int) =
   6         let binaryReader = new BinaryReader (stream)
   7         new Metadata ([])
   8
   9     member this.WriteTo (stream : Stream) =
  10         let memoryStream = new MemoryStream () // To know the serialized meta-data size before writtent them to 'stream'.
  11         let memoryWriter = new BinaryWriter (memoryStream)
  12         List.iter (fun (key : string, value : string) -> memoryWriter.Write key; memoryWriter.Write value) d
  13         (new BinaryWriter (stream)).Write (int memoryStream.Length)
  14         memoryStream.CopyTo (stream)
  15
  16 module API =
  17     module internal MetaData =
  18         let filename = "filename"
  19         let creationTimeKey = "file-creation-time"
  20
  21     let generatKeysPair : Key * Key = Crypto.generateRSAKeysPair
  22
  23     // Encrypt a given file
  24     let encryptFile (inputFilePath : string) (outputFilePath : string) (signaturePrivKey: Key) (cryptPubKey : Key)  =
  25         let keyAES, keyMAC, iv = Crypto.rand 32, Crypto.rand 32, Crypto.rand 16
  26         let fileInfo = new FileInfo (inputFilePath)
  27         use inputStream = new FileStream (inputFilePath, FileMode.Open, FileAccess.Read)
  28         use outputStream = new FileStream (outputFilePath, FileMode.Create, FileAccess.Write)
  29         let writer = new BinaryWriter (outputStream)
  30
  31         writer.Seek (32 + 256, SeekOrigin.Current) |> ignore // Skips mac and signature. They will be written later.
  32
  33         Crypto.encryptRSA cryptPubKey (Array.append keyAES <| Array.append keyMAC iv) |> writer.Write
  34
  35         let (hmacStream, hmac) = Crypto.HMACStream keyMAC outputStream
  36         use cryptoStream = Crypto.encryptAES keyAES iv hmacStream
  37         let cryptoWriter = new BinaryWriter (cryptoStream)
  38
  39         // Write the file metadata.
  40         let metaData = new Metadata ([MetaData.filename, fileInfo.Name
  41                                       MetaData.creationTimeKey, fileInfo.CreationTimeUtc.Ticks.ToString ()])
  42         metaData.WriteTo cryptoStream
  43
  44         // Write the content of the file.
  45         inputStream.CopyTo cryptoStream
  46         cryptoStream.FlushFinalBlock ()
  47
  48         // Write the HMAC at the begining of the file.
  49         outputStream.Position <- 0L
  50         writer.Write hmac.Hash
  51
  52         // Write the signature.
  53         Crypto.signRSA signaturePrivKey hmac.Hash |> writer.Write
  54         ()
  55
  56     let decryptFile (sourceFilePath : string) (targetDirPath : string) (signaturePubKey: Key) (decryptPrivKey : Key) =
  57         ()