/// <summary>
/// Декодирование зашифрованного сессионного ключа из BLOB
/// в структуру.
/// </summary>
///
/// <param name="cspObject"><see cref="GostWrappedKeyObject"/></param>
/// <param name="data">BLOB</param>
///
/// <argnull name="data" />
/// <argnull name="cspObject" />
/// <exception cref="CryptographicException">При ошибках
/// декодирования структуры.</exception>
///
/// <intdoc><para>Аналог в MS отсутствует, часть реализации
/// присутствует в ImportKey. </para></intdoc>
///
/// <unmanagedperm action="LinkDemand" />
internal static void DecodeSimpleBlob(GostWrappedKeyObject cspObject, byte[] data)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (cspObject == null)
{
throw new ArgumentNullException("cspObject");
}
if (data.Length < 16 + 0)
{
throw new CryptographicException(GostConstants.NTE_BAD_DATA);
}
// CRYPT_SIMPLEBLOB_HEADER_->BLOB_HEADER.aiKeyAlg ->4
uint aiKeyAlg = BitConverter.ToUInt32(data, 4);
if (aiKeyAlg != GostConstants.CALG_G28147)
{
throw new CryptographicException(GostConstants.NTE_BAD_DATA);
}
// CRYPT_SIMPLEBLOB_HEADER_-> 8 (Magic, EncryptKeyAlgId)
uint magic = BitConverter.ToUInt32(data, 8);
if (magic != GostConstants.SIMPLEBLOB_MAGIC)
{
throw new CryptographicException(GostConstants.NTE_BAD_DATA);
}
uint EncryptKeyAlgId = BitConverter.ToUInt32(data, 12);
if (EncryptKeyAlgId != GostConstants.CALG_G28147)
{
throw new CryptographicException(GostConstants.NTE_BAD_DATA);
}
// CRYPT_SIMPLEBLOB_->bSV
int pos = 16;
cspObject._ukm = new byte[GostConstants.SEANCE_VECTOR_LEN];
Array.Copy(data, pos, cspObject._ukm, 0, GostConstants.SEANCE_VECTOR_LEN);
pos += GostConstants.SEANCE_VECTOR_LEN;
// CRYPT_SIMPLEBLOB_->bEncryptedKey
cspObject._encryptedKey = new byte[GostConstants.G28147_KEYLEN];
Array.Copy(data, pos, cspObject._encryptedKey, 0, GostConstants.G28147_KEYLEN);
pos += GostConstants.G28147_KEYLEN;
// CRYPT_SIMPLEBLOB_->bMacKey
cspObject._mac = new byte[GostConstants.EXPORT_IMIT_SIZE];
Array.Copy(data, pos, cspObject._mac, 0, GostConstants.EXPORT_IMIT_SIZE);
pos += GostConstants.EXPORT_IMIT_SIZE;
// CRYPT_SIMPLEBLOB_->bEncryptionParamSet
byte[] tmp = new byte[data.Length - pos];
Array.Copy(data, pos, tmp, 0, data.Length - pos);
cspObject._encryptionParamSet = AsnHelper.DecodeGost28147_89_BlobParameters(tmp);
}
/// <summary>
/// Кодирование сессионного ключа в SIMPLE BLOB.
/// </summary>
///
/// <param name="cspObject">Зашифрованный сессионный ключ.</param>
/// <param name="algid">Алгоритм зашифрованного ключа.</param>
///
/// <returns>BLOB</returns>
///
/// <exception cref="CryptographicException">При ошибках
/// кодирования структуры.</exception>
/// <argnull name="cspObject" />
///
/// <intdoc><para>Аналог в MS отсутствует, часть реализации
/// присутствует в ImportKey. </para></intdoc>
///
/// <unmanagedperm action="LinkDemand" />
internal static byte[] EncodeSimpleBlob(GostWrappedKeyObject cspObject, int algid)
{
if (cspObject == null)
{
throw new ArgumentNullException("cspObject");
}
byte[] par = AsnHelper.EncodeGost28147_89_BlobParameters(
cspObject._encryptionParamSet);
byte[] ret = new byte[16
+ GostConstants.SEANCE_VECTOR_LEN
+ GostConstants.G28147_KEYLEN
+ GostConstants.EXPORT_IMIT_SIZE
+ par.Length];
int pos = 0;
// CRYPT_SIMPLEBLOB_->CRYPT_SIMPLEBLOB_HEADER
ret[pos] = GostConstants.SIMPLEBLOB;
pos++;
ret[pos] = GostConstants.CSP_CUR_BLOB_VERSION;
pos++;
pos += 2; // Reserved
byte[] balgid = BitConverter.GetBytes(algid);
Array.Copy(balgid, 0, ret, pos, 4);
pos += 4;
byte[] magic = BitConverter.GetBytes(GostConstants.SIMPLEBLOB_MAGIC);
Array.Copy(magic, 0, ret, pos, 4);
pos += 4;
byte[] ealgid = BitConverter.GetBytes(GostConstants.CALG_G28147);
Array.Copy(ealgid, 0, ret, pos, 4);
pos += 4;
// CRYPT_SIMPLEBLOB_->bSV
Array.Copy(cspObject._ukm, 0, ret, pos, GostConstants.SEANCE_VECTOR_LEN);
pos += GostConstants.SEANCE_VECTOR_LEN;
// CRYPT_SIMPLEBLOB_->bEncryptedKey
Array.Copy(cspObject._encryptedKey, 0, ret, pos, GostConstants.G28147_KEYLEN);
pos += GostConstants.G28147_KEYLEN;
// CRYPT_SIMPLEBLOB_->bMacKey
Array.Copy(cspObject._mac, 0, ret, pos, GostConstants.EXPORT_IMIT_SIZE);
pos += GostConstants.EXPORT_IMIT_SIZE;
// CRYPT_SIMPLEBLOB_->bEncryptionParamSet
Array.Copy(par, 0, ret, pos, par.Length);
return(ret);
}