X-Git-Url: http://git.euphorik.ch/?a=blobdiff_plain;f=labo2-fsharp%2FCryptoFile%2FAPI.fs;h=d4b9ad56d7070faaecee0a42ea3ae6bf3d3c38ef;hb=f88f22ebc8d780fbd86358bf95dffcfb3803f509;hp=250bdbe22786dc140cb8b343961646b51e2cc383;hpb=61a8b3492e89e883b23c158eb52ba2b070234df8;p=crypto_lab2.git

diff --git a/labo2-fsharp/CryptoFile/API.fs b/labo2-fsharp/CryptoFile/API.fs
index 250bdbe..d4b9ad5 100644
--- a/labo2-fsharp/CryptoFile/API.fs
+++ b/labo2-fsharp/CryptoFile/API.fs
@@ -24,22 +24,24 @@ type internal Metadata (d: (string * string) list) =
                     | _ -> 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 keyAES, keyMAC, iv = Crypto.rand 16, Crypto.rand 32, Crypto.rand 16
         let fileInfo = new FileInfo (inputFilePath)
-        use inputStream = new FileStream (inputFilePath, FileMode.Open, FileAccess.Read)
+        use inputStream = fileInfo.OpenRead ()
         use outputStream = new FileStream (outputFilePath, FileMode.Create, FileAccess.Write)
         let 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
@@ -47,8 +49,8 @@ module API =
         let cryptoWriter = new BinaryWriter (cryptoStream)
 
         // Write the file metadata.
-        let metaData = new Metadata ([Metadata.filenameKey, fileInfo.Name
-                                      Metadata.modificationTimeKey, fileInfo.LastWriteTimeUtc.Ticks.ToString ()])
+        let metaData = new Metadata ([MetadataKeys.filename, fileInfo.Name
+                                      MetadataKeys.modificationTime, fileInfo.LastWriteTimeUtc.Ticks.ToString ()])
         metaData.WriteTo cryptoStream
 
         // Write the content of the file.
@@ -62,6 +64,10 @@ module API =
         // 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)
@@ -71,9 +77,9 @@ module API =
             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
@@ -90,8 +96,8 @@ module API =
         let metadata = new 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 filePath = Path.Combine (targetDirPath, metadata.get MetadataKeys.filename)
+        let modificationTime = new DateTime (metadata.get MetadataKeys.modificationTime |> int64)
         let fileInfo = new FileInfo (filePath)
         using (fileInfo.Create ()) <| fun outputStream -> cryptoStream.CopyTo outputStream
         fileInfo.LastWriteTimeUtc <- modificationTime