public void AddCertificate(X509Certificate x509)
{
AgileCertificateEntry ace = new AgileCertificateEntry();
ace.x509 = x509;
certList.Add(ace);
}
/**
* instead of a password, it's also possible to decrypt via certificate.
* Warning: this code is experimental and hasn't been validated
*
* @see <a href="http://social.msdn.microsoft.com/Forums/en-US/cc9092bb-0c82-4b5b-ae21-abf643bdb37c/agile-encryption-with-certificates">Agile encryption with certificates</a>
*
* @param keyPair
* @param x509
* @return true, when the data can be successfully decrypted with the given private key
* @throws GeneralSecurityException
*/
public bool VerifyPassword(KeyPair keyPair, X509Certificate x509)
{
AgileEncryptionVerifier ver = (AgileEncryptionVerifier)builder.GetVerifier();
AgileEncryptionHeader header = (AgileEncryptionHeader)builder.GetHeader();
HashAlgorithm hashAlgo = header.HashAlgorithm;
CipherAlgorithm cipherAlgo = header.CipherAlgorithm;
int blockSize = header.BlockSize;
AgileCertificateEntry ace = null;
foreach (AgileCertificateEntry aceEntry in ver.GetCertificates())
{
if (x509.Equals(aceEntry.x509))
{
ace = aceEntry;
break;
}
}
if (ace == null)
{
return(false);
}
Cipher cipher = Cipher.GetInstance("RSA");
cipher.Init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
byte[] keyspec = cipher.DoFinal(ace.encryptedKey);
SecretKeySpec secretKey = new SecretKeySpec(keyspec, ver.CipherAlgorithm.jceId);
Mac x509Hmac = CryptoFunctions.GetMac(hashAlgo);
x509Hmac.Init(secretKey);
byte[] certVerifier = x509Hmac.DoFinal(ace.x509.GetEncoded());
byte[] vec = CryptoFunctions.GenerateIv(hashAlgo, header.KeySalt, kIntegrityKeyBlock, blockSize);
cipher = GetCipher(secretKey, cipherAlgo, ver.ChainingMode, vec, Cipher.DECRYPT_MODE);
byte[] hmacKey = cipher.DoFinal(header.GetEncryptedHmacKey());
hmacKey = GetBlock0(hmacKey, hashAlgo.hashSize);
vec = CryptoFunctions.GenerateIv(hashAlgo, header.KeySalt, kIntegrityValueBlock, blockSize);
cipher = GetCipher(secretKey, cipherAlgo, ver.ChainingMode, vec, Cipher.DECRYPT_MODE);
byte[] hmacValue = cipher.DoFinal(header.GetEncryptedHmacValue());
hmacValue = GetBlock0(hmacValue, hashAlgo.hashSize);
if (Arrays.Equals(ace.certVerifier, certVerifier))
{
SetSecretKey(secretKey);
SetIntegrityHmacKey(hmacKey);
SetIntegrityHmacValue(hmacValue);
return(true);
}
else
{
return(false);
}
}
protected internal AgileEncryptionVerifier(EncryptionDocument ed)
{
IEnumerator <CT_KeyEncryptor> encList = ed.GetEncryption().keyEncryptors.keyEncryptor.GetEnumerator();
CT_PasswordKeyEncryptor keyData;
try
{
//keyData = encList.Next().EncryptedPasswordKey;
encList.MoveNext();
keyData = encList.Current.Item as CT_PasswordKeyEncryptor;
if (keyData == null)
{
throw new NullReferenceException("encryptedKey not Set");
}
}
catch (Exception e)
{
throw new EncryptedDocumentException("Unable to parse keyData", e);
}
int keyBits = (int)keyData.keyBits;
CipherAlgorithm ca = CipherAlgorithm.FromXmlId(keyData.cipherAlgorithm.ToString(), keyBits);
CipherAlgorithm = (ca);
int hashSize = (int)keyData.hashSize;
HashAlgorithm ha = HashAlgorithm.FromEcmaId(keyData.hashAlgorithm.ToString());
HashAlgorithm = (ha);
if (HashAlgorithm.hashSize != hashSize)
{
throw new EncryptedDocumentException("Unsupported hash algorithm: " +
keyData.hashAlgorithm + " @ " + hashSize + " bytes");
}
SpinCount = (int)(keyData.spinCount);
EncryptedVerifier = (keyData.encryptedVerifierHashInput);
Salt = (keyData.saltValue);
EncryptedKey = (keyData.encryptedKeyValue);
EncryptedVerifierHash = (keyData.encryptedVerifierHashValue);
int saltSize = (int)keyData.saltSize;
if (saltSize != Salt.Length)
{
throw new EncryptedDocumentException("Invalid salt size");
}
switch (keyData.cipherChaining)
{
case ST_CipherChaining.ChainingModeCBC:
ChainingMode = (ChainingMode.cbc);
break;
case ST_CipherChaining.ChainingModeCFB:
ChainingMode = (ChainingMode.cfb);
break;
default:
throw new EncryptedDocumentException("Unsupported chaining mode - " + keyData.cipherChaining.ToString());
}
//if (!encList.HasNext()) return;
try
{
//CertificateFactory cf = CertificateFactory.GetInstance("X.509");
while (encList.MoveNext())
{
CT_CertificateKeyEncryptor certKey = encList.Current.Item as CT_CertificateKeyEncryptor;
AgileCertificateEntry ace = new AgileCertificateEntry();
ace.certVerifier = certKey.certVerifier;
ace.encryptedKey = certKey.encryptedKeyValue;
ace.x509 = new X509Certificate(X509CertificateStructure.GetInstance(certKey.X509Certificate));
certList.Add(ace);
}
}
catch (Exception e)
{
throw new EncryptedDocumentException("can't parse X509 certificate", e);
}
}
