m_acc, m_nk;
size_t m_idx;
// Track nonce reuse; assert in debug but continue
bool m_used;
};
/// \brief Poly1305 message authentication code
/// \tparam T class derived from BlockCipherDocumentation with 16-byte key and 16-byte blocksize
/// \details Poly1305-AES is a state-of-the-art message-authentication code suitable for a wide
/// variety of applications. Poly1305-AES computes a 16-byte authenticator of a variable-length
/// message, using a 16-byte AES key, a 16-byte additional key, and a 16-byte nonce.
/// \details The key is 32 bytes and a concatenation key = {k,s}, where
/// k is the AES key and r is additional key that gets clamped.
/// The key is clamped internally so there is no need to perform the operation
/// before setting the key.
/// \details Each message must have a unique security context, which means either the key or nonce
/// must be changed after each message. It can be accomplished in one of two ways. First, you
/// can create a new Poly1305 object each time its needed.
/// SecByteBlock key(32), nonce(16);
/// prng.GenerateBlock(key, key.size());
/// prng.GenerateBlock(nonce, nonce.size());
///
/// Poly1305 poly1305(key, key.size(), nonce, nonce.size());
/// poly1305.Update(...);
/// poly1305.Final(...);
///
/// \details Second, you can create a Poly1305 object, reuse the key, and set a fresh nonce
/// for each message. The second and subsequent nonces can be generated using GetNextIV().
/// SecByteBlock key(32), nonce(16);
/// prng.GenerateBlock(key, key.size());
/// prng.GenerateBlock(nonce, nonce.size());
///
/// // First message
/// Poly1305 poly1305(key, key.size());
/// poly1305.Resynchronize(nonce);
/// poly1305.Update(...);
/// poly1305.Final(...);
///
/// // Second message
/// poly1305.GetNextIV(prng, nonce);
/// poly1305.Resynchronize(nonce);
/// poly1305.Update(...);
/// poly1305.Final(...);
/// ...
/// \warning Each message must have a unique security context. The Poly1305 class does not
/// enforce a fresh key or nonce for each message. The source code will assert in debug
/// builds to alert of nonce reuse. No action is taken in release builds.
/// \sa Daniel J. Bernstein The Poly1305-AES
/// Message-Authentication Code (20050329) and Andy Polyakov Poly1305 Revised
/// \since Crypto++ 6.0
template
class Poly1305 : public MessageAuthenticationCodeFinal >
{
public:
CRYPTOPP_CONSTANT(DEFAULT_KEYLENGTH=Poly1305_Base::DEFAULT_KEYLENGTH)
;
/// \brief Construct a Poly1305
Poly1305() {}
/// \brief Construct a Poly1305
/// \param key a byte array used to key the cipher
/// \param keyLength the size of the byte array, in bytes
/// \param nonce a byte array used to key the cipher
/// \param nonceLength the size of the byte array, in bytes
/// \details The key is 32 bytes and a concatenation key = {k,s}, where
/// k is the AES key and r is additional key that gets clamped.
/// The key is clamped internally so there is no need to perform the operation
/// before setting the key.
/// \details Each message requires a unique security context. You can use GetNextIV()
/// and Resynchronize() to set a new nonce under a key for a message.
Poly1305(const byte *key, size_t keyLength=DEFAULT_KEYLENGTH, const byte *nonce=NULLPTR, size_t nonceLength=0)
{this->SetKey(key, keyLength, MakeParameters(Name::IV(), ConstByteArrayParameter(nonce, nonceLength)));}
};
////////////////////////////// IETF Poly1305 //////////////////////////////
/// \brief Poly1305-TLS message authentication code base class
/// \details Poly1305TLS_Base is the base class of the IETF's Poly1305 algorithm.
/// \since Crypto++ 8.1
class Poly1305TLS_Base : public FixedKeyLength<32>, public MessageAuthenticationCode
{
public:
static std::string StaticAlgorithmName() {return std::string("Poly1305TLS");}
CRYPTOPP_CONSTANT(DIGESTSIZE=16)
;
CRYPTOPP_CONSTANT(BLOCKSIZE=16)
;
virtual ~Poly1305TLS_Base() {}
Poly1305TLS_Base() {}
void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms);
void Update(const byte *input, size_t length);
void TruncatedFinal(byte *mac, size_t size);
void Restart();
unsigned int BlockSize() const {return BLOCKSIZE;}
unsigned int DigestSize() const {return DIGESTSIZE;}
protected:
// Accumulated hash, clamped r-key, and encrypted nonce
FixedSizeAlignedSecBlock m_h;
FixedSizeAlignedSecBlock m_r;
FixedSizeAlignedSecBlock m_n;
// Accumulated message bytes and index
FixedSizeAlignedSecBlock m_acc;
size_t m_idx;
};
/// \brief Poly1305-TLS message authentication code
/// \details This is the IETF's variant of Bernstein's Poly1305 from RFC 8439.
/// IETF Poly1305 is called Poly1305TLS in the Crypto++ library. It is
/// _slightly_ different from the Bernstein implementation. Poly1305-TLS
/// can be used for cipher suites
/// TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
/// TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, and
/// TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256.
/// \details The key is 32 bytes and a concatenation key = {r,s}, where
/// r is additional key that gets clamped and s is the nonce.
/// The key is clamped internally so there is no need to perform the operation
/// before setting the key.
/// \details Each message must have a unique security context, which means the key
/// must be changed after each message. It can be accomplished in one of two ways.
/// First, you can create a new Poly1305 object with a new key each time its needed.
/// SecByteBlock key(32);
/// prng.GenerateBlock(key, key.size());
///
/// Poly1305TLS poly1305(key, key.size());
/// poly1305.Update(...);
/// poly1305.Final(...);
///
/// \details Second, you can create a Poly1305 object, and use a new key for each
/// message. The keys can be generated directly using a RandomNumberGenerator()
/// derived class.
/// SecByteBlock key(32);
/// prng.GenerateBlock(key, key.size());
///
/// // First message
/// Poly1305TLS poly1305(key, key.size());
/// poly1305.Update(...);
/// poly1305.Final(...);
///
/// // Second message
/// prng.GenerateBlock(key, key.size());
/// poly1305.SetKey(key, key.size());
/// poly1305.Update(...);
/// poly1305.Final(...);
/// ...
/// \warning Each message must have a unique security context. The Poly1305-TLS class
/// does not enforce a fresh key or nonce for each message.
/// \since Crypto++ 8.1
/// \sa MessageAuthenticationCode(), RFC
/// 8439, ChaCha20 and Poly1305 for IETF Protocols
DOCUMENTED_TYPEDEF(MessageAuthenticationCodeFinal, Poly1305TLS)
;
NAMESPACE_END
#endif // CRYPTOPP_POLY1305_H