public byte[] UnwrapMasterKey(AesKey keyEncryptingKey, byte fileVersionMajor)
{
byte[] wrappedKeyData = GetKeyData();
KeyWrapSalt salt = Salt;
if (fileVersionMajor <= 1)
{
// Due to a bug in 1.1 and earlier we only used a truncated part of the key and salt :-(
// Compensate for this here. Users should be warned if FileVersionMajor <= 1 .
byte[] badKey = new byte[keyEncryptingKey.Length];
Array.Copy(keyEncryptingKey.GetBytes(), 0, badKey, 0, 4);
keyEncryptingKey = new AesKey(badKey);
byte[] badSalt = new byte[salt.Length];
Array.Copy(salt.GetBytes(), 0, badSalt, 0, 4);
salt = new KeyWrapSalt(badSalt);
}
byte[] unwrappedKeyData;
using (KeyWrap keyWrap = new KeyWrap(keyEncryptingKey, salt, Iterations, KeyWrapMode.AxCrypt))
{
unwrappedKeyData = keyWrap.Unwrap(wrappedKeyData);
}
return(unwrappedKeyData);
}
public static void TestMethodsEtc()
{
KeyWrapSalt salt = null;
Assert.DoesNotThrow(() =>
{
salt = new KeyWrapSalt(16);
Assert.That(salt.Length, Is.EqualTo(16), "The length should be what was asked for.");
Assert.That(salt.GetBytes(), Is.Not.EquivalentTo(new byte[16]), "A random salt is not likely to be all zeros.");
salt = new KeyWrapSalt(24);
Assert.That(salt.Length, Is.EqualTo(24), "The length should be what was asked for.");
Assert.That(salt.GetBytes(), Is.Not.EquivalentTo(new byte[24]), "A random salt is not likely to be all zeros.");
salt = new KeyWrapSalt(32);
Assert.That(salt.Length, Is.EqualTo(32), "The length should be what was asked for.");
Assert.That(salt.GetBytes(), Is.Not.EquivalentTo(new byte[32]), "A random salt is not likely to be all zeros.");
salt = new KeyWrapSalt(new byte[16]);
Assert.That(salt.GetBytes(), Is.EquivalentTo(new byte[16]), "A salt with all zeros was requested.");
salt = new KeyWrapSalt(new byte[24]);
Assert.That(salt.GetBytes(), Is.EquivalentTo(new byte[24]), "A salt with all zeros was requested.");
salt = new KeyWrapSalt(new byte[32]);
Assert.That(salt.GetBytes(), Is.EquivalentTo(new byte[32]), "A salt with all zeros was requested.");
salt = new KeyWrapSalt(new byte[0]);
Assert.That(salt.Length, Is.EqualTo(0), "As a special case, zero length salt is supported - equivalent to no salt.");
}
);
Assert.Throws <ArgumentNullException>(() =>
{
salt = new KeyWrapSalt(null);
});
Assert.Throws <InternalErrorException>(() =>
{
salt = new KeyWrapSalt(0);
});
Assert.Throws <InternalErrorException>(() =>
{
salt = new KeyWrapSalt(-16);
});
Assert.Throws <InternalErrorException>(() =>
{
salt = new KeyWrapSalt(48);
});
Assert.Throws <InternalErrorException>(() =>
{
salt = new KeyWrapSalt(new byte[12]);
});
}
public static void TestAesKeyThumbprintMethods()
{
AesKey key1 = new AesKey(new byte[] { 5, 6, 7, 8, 2, 4, 55, 77, 34, 65, 89, 12, 45, 87, 54, 255 });
AesKey key2 = new AesKey(new byte[] { 5, 6, 7, 8, 2, 4, 55, 77, 34, 65, 89, 12, 45, 87, 54, 255 });
KeyWrapSalt salt1 = new KeyWrapSalt(16);
KeyWrapSalt salt2 = new KeyWrapSalt(salt1.GetBytes());
AesKeyThumbprint thumbprint1 = new AesKeyThumbprint(key1, salt1, 10);
AesKeyThumbprint thumbprint2 = new AesKeyThumbprint(key2, salt2, 10);
Assert.That(thumbprint1 == thumbprint2, "Two thumb prints made from the same key and salt bytes, although different AesKey instances should be equivalent.");
AesKeyThumbprint thumbprint3 = new AesKeyThumbprint(new AesKey(), new KeyWrapSalt(AesKey.DefaultKeyLength), 10);
Assert.That(thumbprint2 != thumbprint3, "Two very different keys and salts should not be equivalent.");
}
protected void Set(byte[] wrapped, KeyWrapSalt salt, long iterations)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
if (wrapped.Length != 16 + 8)
{
throw new ArgumentException("wrapped must be 128 bits + 8 bytes.");
}
if (salt == null)
{
throw new ArgumentNullException("salt");
}
if (salt.Length != 16)
{
throw new ArgumentException("salt must have same length as the wrapped key, i.e. 128 bits.");
}
Array.Copy(wrapped, 0, GetDataBlockBytesReference(), 0, wrapped.Length);
Array.Copy(salt.GetBytes(), 0, GetDataBlockBytesReference(), 16 + 8, salt.Length);
byte[] iterationsBytes = iterations.GetLittleEndianBytes();
Array.Copy(iterationsBytes, 0, GetDataBlockBytesReference(), 16 + 8 + 16, sizeof(uint));
}
