let rsaKeySize = 2048
let aesKeySize = 128
+ exception KeySizeError
+ exception IVSizeError
+
/// Returns a cryptographically strong sequence of bytes.
let rand size : byte[] =
let result = Array.zeroCreate size
let encryptRSA (publicKey: Key) (plaindata: Data) : Data =
use rsa = new RSACryptoServiceProvider (rsaKeySize)
rsa.FromXmlString publicKey
- rsa.Encrypt (plaindata, false) // Uses PKCS#1 v1.5 padding.
+ rsa.Encrypt (plaindata, true) // Uses padding OAEP (PKCS#1 v2).
let decryptRSA (privateKey: Key) (cipherdata: Data) : Data =
use rsa = new RSACryptoServiceProvider (rsaKeySize)
rsa.FromXmlString privateKey
- rsa.Decrypt (cipherdata, false) // Uses PKCS#1 v1.5 padding.
+ rsa.Decrypt (cipherdata, true) // Uses padding OAEP (PKCS#1 v2).
/// Produces a signature from a given hash.
let signRSA (privKey: Key) (sha256: Data) : Data =
/// Returns an encrypted output stream.
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)
+ if key.Length <> aesKeySize / 8 then raise KeySizeError
+ if iv.Length <> 16 then raise IVSizeError
+ use aes = new AesCryptoServiceProvider (KeySize = aesKeySize) // Default mode is CBC.
+ new CryptoStream (outputStream, aes.CreateEncryptor (key, iv), CryptoStreamMode.Write)
/// Returns a decrypted input stream.
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)
+ if key.Length <> aesKeySize / 8 then raise KeySizeError
+ if iv.Length <> 16 then raise IVSizeError
+ use aes = new AesCryptoServiceProvider (KeySize = aesKeySize)
+ new CryptoStream (inputStream, aes.CreateDecryptor (key, iv), 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)
+ if key.Length <> 32 then raise KeySizeError
let hmac = new HMACSHA256 (key)
new CryptoStream (outputStream, hmac, CryptoStreamMode.Write) :> Stream, hmac
let ComputeHMAC (key: byte[]) (inputStream: Stream) : byte[] =
- assert (key.Length = 32)
+ if key.Length <> 32 then raise KeySizeError
let hmac = new HMACSHA256 (key)
hmac.ComputeHash inputStream
\ No newline at end of file