/// <summary>Opens a SealedPublicKeyBox</summary>
/// <param name="cipherText">The cipherText to be opened.</param>
/// <param name="recipientSecretKey">The recipient's secret key.</param>
/// <param name="recipientPublicKey">The recipient's public key.</param>
/// <returns>The decrypted message.</returns>
/// <exception cref="KeyOutOfRangeException"></exception>
/// <exception cref="CryptographicException"></exception>
public static byte[] Open(byte[] cipherText, byte[] recipientSecretKey, byte[] recipientPublicKey)
{
//validate the length of the recipient secret key
if (recipientSecretKey == null || recipientSecretKey.Length != RecipientSecretKeyBytes)
{
throw new KeyOutOfRangeException("recipientPublicKey",
(recipientSecretKey == null) ? 0 : recipientSecretKey.Length,
string.Format("recipientSecretKey must be {0} bytes in length.", RecipientSecretKeyBytes));
}
//validate the length of the recipient public key
if (recipientPublicKey == null || recipientPublicKey.Length != RecipientPublicKeyBytes)
{
throw new KeyOutOfRangeException("recipientPublicKey",
(recipientPublicKey == null) ? 0 : recipientPublicKey.Length,
string.Format("recipientPublicKey must be {0} bytes in length.", RecipientPublicKeyBytes));
}
var buffer = new byte[cipherText.Length - CryptoBoxSealbytes];
var ret = SodiumLibrary.crypto_box_seal_open(buffer, cipherText, cipherText.Length, recipientPublicKey,
recipientSecretKey);
if (ret != 0)
{
throw new CryptographicException("Failed to open SealedBox");
}
return(buffer);
}
