protected internal static byte[] hashInput(IEncryptionInfoBuilder builder, byte[] pwHash, byte[] blockKey, byte[] inputKey, int cipherMode)
{
EncryptionVerifier ver = builder.GetVerifier();
AgileDecryptor dec = (AgileDecryptor)builder.GetDecryptor();
int keySize = dec.GetKeySizeInBytes();
int blockSize = dec.GetBlockSizeInBytes();
HashAlgorithm hashAlgo = ver.HashAlgorithm;
byte[] salt = ver.Salt;
byte[] intermedKey = CryptoFunctions.GenerateKey(pwHash, hashAlgo, blockKey, keySize);
ISecretKey skey = new SecretKeySpec(intermedKey, ver.CipherAlgorithm.jceId);
byte[] iv = CryptoFunctions.GenerateIv(hashAlgo, salt, null, blockSize);
Cipher cipher = CryptoFunctions.GetCipher(skey, ver.CipherAlgorithm, ver.ChainingMode, iv, cipherMode);
byte[] hashFinal;
try {
inputKey = CryptoFunctions.GetBlock0(inputKey, GetNextBlockSize(inputKey.Length, blockSize));
hashFinal = cipher.DoFinal(inputKey);
return(hashFinal);
} catch (Exception e) {
throw new EncryptedDocumentException(e);
}
}
public AgileCipherInputStream(DocumentInputStream stream, long size,
IEncryptionInfoBuilder builder, AgileDecryptor decryptor)
: base(stream, size, 4096, builder, decryptor)
{
this.builder = builder;
this.decryptor = decryptor;
}
public void Initialize(EncryptionInfo info, ILittleEndianInput dis)
{
this.info = info;
EncryptionDocument ed = ParseDescriptor((DocumentInputStream)dis);
header = new AgileEncryptionHeader(ed);
verifier = new AgileEncryptionVerifier(ed);
if (info.VersionMajor == EncryptionMode.Agile.VersionMajor &&
info.VersionMinor == EncryptionMode.Agile.VersionMinor)
{
decryptor = new AgileDecryptor(this);
encryptor = new AgileEncryptor(this);
}
}
public void Initialize(EncryptionInfo info, CipherAlgorithm cipherAlgorithm, HashAlgorithm hashAlgorithm, int keyBits, int blockSize, ChainingMode chainingMode)
{
this.info = info;
if (cipherAlgorithm == null)
{
cipherAlgorithm = CipherAlgorithm.aes128;
}
if (cipherAlgorithm == CipherAlgorithm.rc4)
{
throw new EncryptedDocumentException("RC4 must not be used with agile encryption.");
}
if (hashAlgorithm == null)
{
hashAlgorithm = HashAlgorithm.sha1;
}
if (chainingMode == null)
{
chainingMode = ChainingMode.cbc;
}
if (!(chainingMode == ChainingMode.cbc || chainingMode == ChainingMode.cfb))
{
throw new EncryptedDocumentException("Agile encryption only supports CBC/CFB chaining.");
}
if (keyBits == -1)
{
keyBits = cipherAlgorithm.defaultKeySize;
}
if (blockSize == -1)
{
blockSize = cipherAlgorithm.blockSize;
}
bool found = false;
foreach (int ks in cipherAlgorithm.allowedKeySize)
{
found |= (ks == keyBits);
}
if (!found)
{
throw new EncryptedDocumentException("KeySize " + keyBits + " not allowed for Cipher " + cipherAlgorithm.ToString());
}
header = new AgileEncryptionHeader(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode);
verifier = new AgileEncryptionVerifier(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode);
decryptor = new AgileDecryptor(this);
encryptor = new AgileEncryptor(this);
}
/**
* Generate an HMAC, as specified in [RFC2104], of the encrypted form of the data (message),
* which the DataIntegrity element will verify by using the Salt generated in step 2 as the key.
* Note that the entire EncryptedPackage stream (1), including the StreamSize field, MUST be
* used as the message.
*
* Encrypt the HMAC as in step 3 by using a blockKey byte array consisting of the following bytes:
* 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, and 0x33.
**/
protected void UpdateIntegrityHMAC(FileInfo tmpFile, int oleStreamSize)
{
// as the integrity hmac needs to contain the StreamSize,
// it's not possible to calculate it on-the-fly while buffering
// TODO: add stream size parameter to GetDataStream()
AgileEncryptionVerifier ver = builder.GetVerifier();
HashAlgorithm hashAlgo = ver.HashAlgorithm;
Mac integrityMD = CryptoFunctions.GetMac(hashAlgo);
integrityMD.Init(new SecretKeySpec(integritySalt, hashAlgo.jceHmacId));
byte[] buf = new byte[1024];
LittleEndian.PutLong(buf, 0, oleStreamSize);
integrityMD.Update(buf, 0, LittleEndian.LONG_SIZE);
FileStream fis = tmpFile.Create();
try {
int readBytes;
while ((readBytes = fis.Read(buf, 0, buf.Length)) > 0)
{
integrityMD.Update(buf, 0, readBytes);
}
} finally {
fis.Close();
}
byte[] hmacValue = integrityMD.DoFinal();
AgileEncryptionHeader header = builder.GetHeader();
int blockSize = header.BlockSize;
byte[] iv = CryptoFunctions.GenerateIv(header.HashAlgorithm, header.KeySalt, AgileDecryptor.kIntegrityValueBlock, blockSize);
Cipher cipher = CryptoFunctions.GetCipher(GetSecretKey(), header.CipherAlgorithm, header.ChainingMode, iv, Cipher.ENCRYPT_MODE);
byte[] hmacValueFilled = GetBlock0(hmacValue, AgileDecryptor.GetNextBlockSize(hmacValue.Length, blockSize));
byte[] encryptedHmacValue = cipher.DoFinal(hmacValueFilled);
header.SetEncryptedHmacValue(encryptedHmacValue);
}
// TODO: calculate integrity hmac while Reading the stream
// for a post-validation of the data
protected override Cipher InitCipherForBlock(Cipher cipher, int block)
{
return(AgileDecryptor.InitCipherForBlock(cipher, block, false, builder, decryptor.GetSecretKey(), Cipher.DECRYPT_MODE));
}
public override void ConfirmPassword(String password, byte[] keySpec, byte[] keySalt, byte[] verifier, byte[] verifierSalt, byte[] integritySalt)
{
AgileEncryptionVerifier ver = builder.GetVerifier();
ver.Salt = (/*setter*/ verifierSalt);
AgileEncryptionHeader header = builder.GetHeader();
header.KeySalt = (/*setter*/ keySalt);
HashAlgorithm hashAlgo = ver.HashAlgorithm;
int blockSize = header.BlockSize;
pwHash = HashPassword(password, hashAlgo, verifierSalt, ver.SpinCount);
/**
* encryptedVerifierHashInput: This attribute MUST be generated by using the following steps:
* 1. Generate a random array of bytes with the number of bytes used specified by the saltSize
* attribute.
* 2. Generate an encryption key as specified in section 2.3.4.11 by using the user-supplied password,
* the binary byte array used to create the saltValue attribute, and a blockKey byte array
* consisting of the following bytes: 0xfe, 0xa7, 0xd2, 0x76, 0x3b, 0x4b, 0x9e, and 0x79.
* 3. Encrypt the random array of bytes generated in step 1 by using the binary form of the saltValue
* attribute as an Initialization vector as specified in section 2.3.4.12. If the array of bytes is not an
* integral multiple of blockSize bytes, pad the array with 0x00 to the next integral multiple of
* blockSize bytes.
* 4. Use base64 to encode the result of step 3.
*/
byte[] encryptedVerifier = AgileDecryptor.hashInput(builder, pwHash, AgileDecryptor.kVerifierInputBlock, verifier, Cipher.ENCRYPT_MODE);
ver.EncryptedVerifier = (/*setter*/ encryptedVerifier);
/**
* encryptedVerifierHashValue: This attribute MUST be generated by using the following steps:
* 1. Obtain the hash value of the random array of bytes generated in step 1 of the steps for
* encryptedVerifierHashInput.
* 2. Generate an encryption key as specified in section 2.3.4.11 by using the user-supplied password,
* the binary byte array used to create the saltValue attribute, and a blockKey byte array
* consisting of the following bytes: 0xd7, 0xaa, 0x0f, 0x6d, 0x30, 0x61, 0x34, and 0x4e.
* 3. Encrypt the hash value obtained in step 1 by using the binary form of the saltValue attribute as
* an Initialization vector as specified in section 2.3.4.12. If hashSize is not an integral multiple of
* blockSize bytes, pad the hash value with 0x00 to an integral multiple of blockSize bytes.
* 4. Use base64 to encode the result of step 3.
*/
MessageDigest hashMD = GetMessageDigest(hashAlgo);
byte[] hashedVerifier = hashMD.Digest(verifier);
byte[] encryptedVerifierHash = AgileDecryptor.hashInput(builder, pwHash, AgileDecryptor.kHashedVerifierBlock, hashedVerifier, Cipher.ENCRYPT_MODE);
ver.EncryptedVerifierHash = (/*setter*/ encryptedVerifierHash);
/**
* encryptedKeyValue: This attribute MUST be generated by using the following steps:
* 1. Generate a random array of bytes that is the same size as specified by the
* Encryptor.KeyData.keyBits attribute of the parent element.
* 2. Generate an encryption key as specified in section 2.3.4.11, using the user-supplied password,
* the binary byte array used to create the saltValue attribute, and a blockKey byte array
* consisting of the following bytes: 0x14, 0x6e, 0x0b, 0xe7, 0xab, 0xac, 0xd0, and 0xd6.
* 3. Encrypt the random array of bytes generated in step 1 by using the binary form of the saltValue
* attribute as an Initialization vector as specified in section 2.3.4.12. If the array of bytes is not an
* integral multiple of blockSize bytes, pad the array with 0x00 to an integral multiple of
* blockSize bytes.
* 4. Use base64 to encode the result of step 3.
*/
byte[] encryptedKey = AgileDecryptor.hashInput(builder, pwHash, AgileDecryptor.kCryptoKeyBlock, keySpec, Cipher.ENCRYPT_MODE);
ver.EncryptedKey = (/*setter*/ encryptedKey);
ISecretKey secretKey = new SecretKeySpec(keySpec, ver.CipherAlgorithm.jceId);
SetSecretKey(secretKey);
/*
* 2.3.4.14 DataIntegrity Generation (Agile Encryption)
*
* The DataIntegrity element Contained within an Encryption element MUST be generated by using
* the following steps:
* 1. Obtain the intermediate key by decrypting the encryptedKeyValue from a KeyEncryptor
* Contained within the KeyEncryptors sequence. Use this key for encryption operations in the
* remaining steps of this section.
* 2. Generate a random array of bytes, known as Salt, of the same length as the value of the
* KeyData.HashSize attribute.
* 3. Encrypt the random array of bytes generated in step 2 by using the binary form of the
* KeyData.saltValue attribute and a blockKey byte array consisting of the following bytes:
* 0x5f, 0xb2, 0xad, 0x01, 0x0c, 0xb9, 0xe1, and 0xf6 used to form an Initialization vector as
* specified in section 2.3.4.12. If the array of bytes is not an integral multiple of blockSize
* bytes, pad the array with 0x00 to the next integral multiple of blockSize bytes.
* 4. Assign the encryptedHmacKey attribute to the base64-encoded form of the result of step 3.
* 5. Generate an HMAC, as specified in [RFC2104], of the encrypted form of the data (message),
* which the DataIntegrity element will verify by using the Salt generated in step 2 as the key.
* Note that the entire EncryptedPackage stream (1), including the StreamSize field, MUST be
* used as the message.
* 6. Encrypt the HMAC as in step 3 by using a blockKey byte array consisting of the following bytes:
* 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, and 0x33.
* 7. Assign the encryptedHmacValue attribute to the base64-encoded form of the result of step 6.
*/
this.integritySalt = integritySalt;
try {
byte[] vec = CryptoFunctions.GenerateIv(hashAlgo, header.KeySalt, AgileDecryptor.kIntegrityKeyBlock, header.BlockSize);
Cipher cipher = GetCipher(secretKey, ver.CipherAlgorithm, ver.ChainingMode, vec, Cipher.ENCRYPT_MODE);
byte[] FilledSalt = GetBlock0(integritySalt, AgileDecryptor.GetNextBlockSize(integritySalt.Length, blockSize));
byte[] encryptedHmacKey = cipher.DoFinal(FilledSalt);
header.SetEncryptedHmacKey(encryptedHmacKey);
cipher = Cipher.GetInstance("RSA");
foreach (AgileCertificateEntry ace in ver.GetCertificates())
{
cipher.Init(Cipher.ENCRYPT_MODE, ace.x509.GetPublicKey());
ace.encryptedKey = cipher.DoFinal(GetSecretKey().GetEncoded());
Mac x509Hmac = CryptoFunctions.GetMac(hashAlgo);
x509Hmac.Init(GetSecretKey());
ace.certVerifier = x509Hmac.DoFinal(ace.x509.GetEncoded());
}
} catch (Exception e) {
throw new EncryptedDocumentException(e);
}
}
protected override Cipher InitCipherForBlock(Cipher existing, int block, bool lastChunk)
{
return(AgileDecryptor.InitCipherForBlock(existing, block, lastChunk, builder, skey, Cipher.ENCRYPT_MODE));
}
