/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef DOM_QUOTA_ENCRYPTEDRANDOMACCESSBLOCKVIEWV1_H_
#define DOM_QUOTA_ENCRYPTEDRANDOMACCESSBLOCKVIEWV1_H_
#include <cstdint>
#include <cstring>
#include "EncryptedRandomAccessBlock.h"
#include "mozilla/Span.h"
namespace mozilla::dom::quota {
/**
* Version 1 interpretation of CipherMetadata of EncryptedRandomAccessBlock
* (byte offsets relative to the start of CipherMetadata, i.e., byte 32 in the
* full block):
*
* --------+-----------------------------------------------+
* offset | field size |
* --------+-----------------------------------------------+
* 0 | Nonce / IV 12 bytes |
* 12 | Authentication tag 16 bytes |
* 28 | Reserved (unused) 4 bytes |
* --------+-----------------------------------------------+
* 32
*/
class EncryptedRandomAccessBlockViewV1 {
public:
static constexpr size_t NonceSize =
12;
static constexpr size_t AuthenticationTagSize =
16;
template <size_t N>
using ConstSpan = Span<
const uint8_t, N>;
template <size_t N>
using MutableSpan = Span<uint8_t, N>;
private:
static constexpr size_t ReservedBytesSize =
4;
static_assert(NonceSize + AuthenticationTagSize + ReservedBytesSize ==
EncryptedRandomAccessBlock::CipherMetadataSize);
public:
explicit EncryptedRandomAccessBlockViewV1(
MutableSpan<NonceSize + AuthenticationTagSize + ReservedBytesSize> aBlock)
: mCipherMetadata(aBlock) {}
/** The AEAD nonce (initialization vector) for this block. */
ConstSpan<NonceSize> Nonce()
const {
return mCipherMetadata.First<NonceSize>();
}
void SetNonce(ConstSpan<NonceSize> aNonce) {
memcpy(mCipherMetadata.data(), aNonce.data(), NonceSize);
}
/** The AEAD authentication tag for this block. */
ConstSpan<AuthenticationTagSize> AuthenticationTag()
const {
return mCipherMetadata.Subspan<NonceSize, AuthenticationTagSize>();
}
void SetAuthenticationTag(
ConstSpan<AuthenticationTagSize> aAuthenticationTag) {
memcpy(mCipherMetadata.data() + NonceSize, aAuthenticationTag.data(),
AuthenticationTagSize);
}
private:
MutableSpan<NonceSize + AuthenticationTagSize + ReservedBytesSize>
mCipherMetadata;
};
}
// namespace mozilla::dom::quota
#endif // DOM_QUOTA_ENCRYPTEDRANDOMACCESSBLOCKVIEWV1_H_
