X-Git-Url: http://git.euphorik.ch/?a=blobdiff_plain;f=labo2-fsharp%2FCryptoFile%2FCrypto.fs;h=c81475b9e24cc6096fb04f07c1e4762ed160ccc8;hb=f88f22ebc8d780fbd86358bf95dffcfb3803f509;hp=34d54fa68cf04673424479a57e91c095bb60c4fe;hpb=beda8d83dc421c479bdcf5ee626ec85ee8555a80;p=crypto_lab2.git

diff --git a/labo2-fsharp/CryptoFile/Crypto.fs b/labo2-fsharp/CryptoFile/Crypto.fs
index 34d54fa..c81475b 100644
--- a/labo2-fsharp/CryptoFile/Crypto.fs
+++ b/labo2-fsharp/CryptoFile/Crypto.fs
@@ -1,13 +1,15 @@
 namespace CryptoFile
 
+open System
+open System.IO
+open System.Security.Cryptography
+
 // Some cryptography primitives specific to CryptoFile.
 module internal Crypto =
-    open System.Security.Cryptography
-    open System.IO
-
     type Data = byte[]
 
     let rsaKeySize = 2048
+    let aesKeySize = 128
 
     /// Returns a cryptographically strong sequence of bytes.
     let rand size : byte[] =
@@ -19,57 +21,53 @@ module internal Crypto =
     /// Generate a new RSA key pair: (public * private).
     let generateRSAKeysPair : Key * Key =
         use rsa = new RSACryptoServiceProvider (rsaKeySize)
-        try
-            rsa.ToXmlString false, rsa.ToXmlString true
-        finally
-            rsa.PersistKeyInCsp <- false
+        rsa.ToXmlString false, rsa.ToXmlString true
 
-    let encryptRSA (publicKey : Key) (plaindata : Data) : Data =
+    let encryptRSA (publicKey: Key) (plaindata: Data) : Data =
         use rsa = new RSACryptoServiceProvider (rsaKeySize)
-        try
-            rsa.FromXmlString publicKey
-            rsa.Encrypt (plaindata, false) // Uses PKCS#1 v1.5 padding.
-        finally
-            rsa.PersistKeyInCsp <- false
+        rsa.FromXmlString publicKey
+        rsa.Encrypt (plaindata, false) // Uses PKCS#1 v1.5 padding.
 
-    let decryptRSA (privateKey : Key) (cipherdata : Data) : Data =
+    let decryptRSA (privateKey: Key) (cipherdata: Data) : Data =
         use rsa = new RSACryptoServiceProvider (rsaKeySize)
-        try
-            rsa.FromXmlString privateKey
-            rsa.Decrypt (cipherdata, false) // Uses PKCS#1 v1.5 padding.
-        finally
-            rsa.PersistKeyInCsp <- false
+        rsa.FromXmlString privateKey
+        rsa.Decrypt (cipherdata, false) // Uses PKCS#1 v1.5 padding.
 
     /// Produces a signature from a given hash.
-    let signRSA (privKey : Key) (sha256 : Data) : Data = 
+    let signRSA (privKey: Key) (sha256: Data) : Data = 
         use rsa = new RSACryptoServiceProvider (rsaKeySize)
-        try
-            rsa.FromXmlString privKey
-            rsa.SignHash (sha256, CryptoConfig.MapNameToOID "SHA256")
-        finally
-            rsa.PersistKeyInCsp <- false
+        rsa.FromXmlString privKey
+        rsa.SignHash (sha256, CryptoConfig.MapNameToOID "SHA256")
 
     /// Verify a signature against a given hash.
-    let verifySignRSA (pubKey : Key) (sha256 : Data) (signature : Data) : bool =
+    let verifySignRSA (pubKey: Key) (sha256: Data) (signature: Data) : bool =
         use rsa = new RSACryptoServiceProvider (rsaKeySize)
-        try
-            rsa.FromXmlString pubKey
-            rsa.VerifyHash (sha256, CryptoConfig.MapNameToOID "SHA256", signature)
-        finally
-            rsa.PersistKeyInCsp <- false
+        rsa.FromXmlString pubKey
+        rsa.VerifyHash (sha256, CryptoConfig.MapNameToOID "SHA256", signature)
 
     /// Returns an encrypted output stream.
-    let encryptAES (key : byte[]) (iv : byte[]) (outputStream : Stream) : Stream =
-        assert (key.Length = 32 && iv.Length = 16)
-        use aes = new AesManaged ()
-        aes.KeySize <- 256
+    let encryptAES (key: byte[]) (iv: byte[]) (outputStream: Stream) : CryptoStream =
+        assert (key.Length = aesKeySize / 8 && iv.Length = 16)
+        use aes = new AesCryptoServiceProvider () // Default mode is CBC.
+        aes.KeySize <- aesKeySize
         let encryptor = aes.CreateEncryptor (key, iv)
-        new CryptoStream (outputStream, encryptor, CryptoStreamMode.Write) :> Stream
+        new CryptoStream (outputStream, encryptor, CryptoStreamMode.Write)
 
     /// Returns a decrypted input stream.
-    let decryptAES (key : byte[]) (iv : byte[]) (inputStream : Stream) : Stream =
-        assert (key.Length = 32 && iv.Length = 16)
-        use aes = new AesManaged ()
-        aes.KeySize <- 256
+    let decryptAES (key: byte[]) (iv: byte[]) (inputStream: Stream) : CryptoStream =
+        assert (key.Length = aesKeySize / 8 && iv.Length = 16)
+        use aes = new AesCryptoServiceProvider ()
+        aes.KeySize <- aesKeySize
         let decryptor = aes.CreateDecryptor (key, iv)
-        new CryptoStream (inputStream, decryptor, CryptoStreamMode.Read) :> Stream
+        new CryptoStream (inputStream, decryptor, CryptoStreamMode.Read)
+
+    // Create a stream to compute the HMAC-SHA256 against all data being written.
+    let HMACStream (key: byte[]) (outputStream: Stream) : Stream * HMACSHA256 = 
+        assert (key.Length = 32)
+        let hmac = new HMACSHA256 (key)
+        new CryptoStream (outputStream, hmac, CryptoStreamMode.Write) :> Stream, hmac
+
+    let ComputeHMAC (key: byte[]) (inputStream: Stream) : byte[] =
+        assert (key.Length = 32)
+        let hmac = new HMACSHA256 (key)
+        hmac.ComputeHash inputStream
\ No newline at end of file