new (stream : Stream) =
let reader = new BinaryReader (stream)
let length = reader.ReadByte () |> int
- new Metadata ([for i in 1..length -> reader.ReadString (), reader.ReadString ()])
+ Metadata ([for _ in 1..length -> reader.ReadString (), reader.ReadString ()])
// Write metadata to a stream.
member this.WriteTo (stream : Stream) =
| _ -> None) d
module API =
- module internal Metadata =
- let filenameKey = "filename"
- let modificationTimeKey = "file-modification-time"
+ module internal MetadataKeys =
+ let filename = "filename"
+ let modificationTime = "file-modification-time"
+
+ let internal (@@) a1 a2 = Array.append a1 a2
let generatKeysPair : Key * Key = Crypto.generateRSAKeysPair
let encryptFile (inputFilePath : string) (outputFilePath : string) (signaturePrivKey: Key) (cryptPubKey : Key) =
- let keyAES, keyMAC, iv = Crypto.rand 32, Crypto.rand 32, Crypto.rand 16
- let fileInfo = new FileInfo (inputFilePath)
- use inputStream = new FileStream (inputFilePath, FileMode.Open, FileAccess.Read)
+ let keyAES, keyMAC, iv = Crypto.rand 16, Crypto.rand 32, Crypto.rand 16
+ let fileInfo = FileInfo (inputFilePath)
+ use inputStream = fileInfo.OpenRead ()
use outputStream = new FileStream (outputFilePath, FileMode.Create, FileAccess.Write)
- let writer = new BinaryWriter (outputStream)
+ use writer = new BinaryWriter (outputStream)
- writer.Seek (32 + 256, SeekOrigin.Current) |> ignore // Skips mac and signature. They will be written later.
+ outputStream.Position <- 32L + 256L // Skips mac and signature. They will be written later.
- Crypto.encryptRSA cryptPubKey (Array.append keyAES <| Array.append keyMAC iv) |> writer.Write
+ Crypto.encryptRSA cryptPubKey (keyAES @@ keyMAC @@ iv) |> writer.Write
// Plaintext -> cryptoStream -> hmacStream -> cyphertext.
let hmacStream, hmac = Crypto.HMACStream keyMAC outputStream
use cryptoStream = Crypto.encryptAES keyAES iv hmacStream
- let cryptoWriter = new BinaryWriter (cryptoStream)
+ use cryptoWriter = new BinaryWriter (cryptoStream)
// Write the file metadata.
- let metaData = new Metadata ([Metadata.filenameKey, fileInfo.Name
- Metadata.modificationTimeKey, fileInfo.LastWriteTimeUtc.Ticks.ToString ()])
+ let metaData = Metadata ([MetadataKeys.filename, fileInfo.Name
+ MetadataKeys.modificationTime, fileInfo.LastWriteTimeUtc.Ticks.ToString ()])
metaData.WriteTo cryptoStream
// Write the content of the file.
// Write the signature.
Crypto.signRSA signaturePrivKey hmac.Hash |> writer.Write
+ // May raise one of the following error:
+ // * IntegrityError
+ // * SignatureMismatch
+ // * UnableToDecryptAESKeys
let decryptFile (sourceFilePath : string) (targetDirPath : string) (signaturePubKey: Key) (decryptPrivKey : Key) =
use inputStream = new FileStream (sourceFilePath, FileMode.Open, FileAccess.Read)
use reader = new BinaryReader (inputStream)
try reader.ReadBytes 256 |> Crypto.decryptRSA decryptPrivKey
with
| :? Security.Cryptography.CryptographicException -> raise UnableToDecryptAESKeys
- let keyAES = keys.[0..31]
- let keyMAC = keys.[32..63]
- let iv = keys.[64..79]
+ let keyAES = keys.[0..15]
+ let keyMAC = keys.[16..47]
+ let iv = keys.[48..63]
// Integrity validation.
let mac' = Crypto.ComputeHMAC keyMAC inputStream
// Decrypt metadata.
inputStream.Position <- 32L + 256L + 256L
use cryptoStream = Crypto.decryptAES keyAES iv inputStream
- let metadata = new Metadata (cryptoStream)
+ let metadata = Metadata cryptoStream
// Create the file and write its content and metadata.
- let filePath = Path.Combine (targetDirPath, metadata.get Metadata.filenameKey)
- let modificationTime = new DateTime (metadata.get Metadata.modificationTimeKey |> int64)
- let fileInfo = new FileInfo (filePath)
+ let filePath = Path.Combine (targetDirPath, metadata.get MetadataKeys.filename)
+ let modificationTime = DateTime (metadata.get MetadataKeys.modificationTime |> int64)
+ let fileInfo = FileInfo filePath
using (fileInfo.Create ()) <| fun outputStream -> cryptoStream.CopyTo outputStream
fileInfo.LastWriteTimeUtc <- modificationTime
\ No newline at end of file