Crypto++ 8.9
Free C++ class library of cryptographic schemes
poly1305.h
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1// poly1305.h - written and placed in the public domain by Jeffrey Walton and Jean-Pierre Munch
2// Based on Andy Polyakov's Base-2^26 scalar multiplication implementation.
3// For more information, see https://www.openssl.org/~appro/cryptogams/.
4
5// The library added Bernstein's Poly1305 classes at Crypto++ 6.0. The IETF
6// uses a slightly different implementation than Bernstein, and the IETF
7// classes were added at Crypto++ 8.1. We wanted to maintain ABI compatibility
8// at the 8.1 release so the original Poly1305 classes were not disturbed.
9// Instead new classes were added for IETF Poly1305. The back-end implementation
10// shares code as expected, however.
11
12/// \file poly1305.h
13/// \brief Classes for Poly1305 message authentication code
14/// \details Poly1305-AES is a state-of-the-art message-authentication code suitable for a wide
15/// variety of applications. Poly1305-AES computes a 16-byte authenticator of a variable-length
16/// message, using a 16-byte AES key, a 16-byte additional key, and a 16-byte nonce.
17/// \details Crypto++ also supplies the IETF's version of Poly1305. It is a slightly different
18/// algorithm than Bernstein's version.
19/// \sa Daniel J. Bernstein <A HREF="http://cr.yp.to/mac/poly1305-20050329.pdf">The Poly1305-AES
20/// Message-Authentication Code (20050329)</A>, <a href="http://tools.ietf.org/html/rfc8439">RFC
21/// 8439, ChaCha20 and Poly1305 for IETF Protocols</a> and Andy Polyakov <A
22/// HREF="http://www.openssl.org/blog/blog/2016/02/15/poly1305-revised/">Poly1305 Revised</A>
23/// \since Poly1305 since Crypto++ 6.0, Poly1305TLS since Crypto++ 8.1
24
25#ifndef CRYPTOPP_POLY1305_H
26#define CRYPTOPP_POLY1305_H
27
28#include "cryptlib.h"
29#include "seckey.h"
30#include "secblock.h"
31#include "argnames.h"
32#include "algparam.h"
33
34NAMESPACE_BEGIN(CryptoPP)
35
36////////////////////////////// Bernstein Poly1305 //////////////////////////////
37
38/// \brief Poly1305 message authentication code base class
39/// \tparam T BlockCipherDocumentation derived class with 16-byte key and 16-byte blocksize
40/// \details Poly1305_Base is the base class of Bernstein's Poly1305 algorithm.
41/// \since Crypto++ 6.0
42template <class T>
43class CRYPTOPP_NO_VTABLE Poly1305_Base : public FixedKeyLength<32, SimpleKeyingInterface::UNIQUE_IV, 16>, public MessageAuthenticationCode
44{
45 CRYPTOPP_COMPILE_ASSERT(T::DEFAULT_KEYLENGTH == 16);
46 CRYPTOPP_COMPILE_ASSERT(T::BLOCKSIZE == 16);
47
48public:
49 static std::string StaticAlgorithmName() {return std::string("Poly1305(") + T::StaticAlgorithmName() + ")";}
50
51 CRYPTOPP_CONSTANT(DIGESTSIZE=T::BLOCKSIZE);
52 CRYPTOPP_CONSTANT(BLOCKSIZE=T::BLOCKSIZE);
53
54 virtual ~Poly1305_Base() {}
55 Poly1305_Base() : m_idx(0), m_used(true) {}
56
57 void Resynchronize (const byte *iv, int ivLength=-1);
58 void GetNextIV (RandomNumberGenerator &rng, byte *iv);
59
60 void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
61 void Update(const byte *input, size_t length);
62 void TruncatedFinal(byte *mac, size_t size);
63 void Restart();
64
65 unsigned int BlockSize() const {return BLOCKSIZE;}
66 unsigned int DigestSize() const {return DIGESTSIZE;}
67
68 std::string AlgorithmProvider() const;
69
70protected:
71 // TODO: No longer needed. Remove at next major version bump
72 void HashBlocks(const byte *input, size_t length, word32 padbit);
73 void HashFinal(byte *mac, size_t length);
74
75 typename T::Encryption m_cipher;
76
77 // Accumulated hash, clamped r-key, and encrypted nonce
81
82 // Accumulated message bytes and index
84 size_t m_idx;
85
86 // Track nonce reuse; assert in debug but continue
87 bool m_used;
88};
89
90/// \brief Poly1305 message authentication code
91/// \tparam T class derived from BlockCipherDocumentation with 16-byte key and 16-byte blocksize
92/// \details Poly1305-AES is a state-of-the-art message-authentication code suitable for a wide
93/// variety of applications. Poly1305-AES computes a 16-byte authenticator of a variable-length
94/// message, using a 16-byte AES key, a 16-byte additional key, and a 16-byte nonce.
95/// \details The key is 32 bytes and a concatenation <tt>key = {k,s}</tt>, where
96/// <tt>k</tt> is the AES key and <tt>r</tt> is additional key that gets clamped.
97/// The key is clamped internally so there is no need to perform the operation
98/// before setting the key.
99/// \details Each message must have a unique security context, which means either the key or nonce
100/// must be changed after each message. It can be accomplished in one of two ways. First, you
101/// can create a new Poly1305 object each time its needed.
102/// <pre> SecByteBlock key(32), nonce(16);
103/// prng.GenerateBlock(key, key.size());
104/// prng.GenerateBlock(nonce, nonce.size());
105///
106/// Poly1305<AES> poly1305(key, key.size(), nonce, nonce.size());
107/// poly1305.Update(...);
108/// poly1305.Final(...);</pre>
109///
110/// \details Second, you can create a Poly1305 object, reuse the key, and set a fresh nonce
111/// for each message. The second and subsequent nonces can be generated using GetNextIV().
112/// <pre> SecByteBlock key(32), nonce(16);
113/// prng.GenerateBlock(key, key.size());
114/// prng.GenerateBlock(nonce, nonce.size());
115///
116/// // First message
117/// Poly1305<AES> poly1305(key, key.size());
118/// poly1305.Resynchronize(nonce);
119/// poly1305.Update(...);
120/// poly1305.Final(...);
121///
122/// // Second message
123/// poly1305.GetNextIV(prng, nonce);
124/// poly1305.Resynchronize(nonce);
125/// poly1305.Update(...);
126/// poly1305.Final(...);
127/// ...</pre>
128/// \warning Each message must have a unique security context. The Poly1305 class does not
129/// enforce a fresh key or nonce for each message. The source code will assert in debug
130/// builds to alert of nonce reuse. No action is taken in release builds.
131/// \sa Daniel J. Bernstein <A HREF="http://cr.yp.to/mac/poly1305-20050329.pdf">The Poly1305-AES
132/// Message-Authentication Code (20050329)</A> and Andy Polyakov <A
133/// HREF="http://www.openssl.org/blog/blog/2016/02/15/poly1305-revised/">Poly1305 Revised</A>
134/// \since Crypto++ 6.0
135template <class T>
136class Poly1305 : public MessageAuthenticationCodeFinal<Poly1305_Base<T> >
137{
138public:
139 CRYPTOPP_CONSTANT(DEFAULT_KEYLENGTH=Poly1305_Base<T>::DEFAULT_KEYLENGTH);
140
141 /// \brief Construct a Poly1305
143
144 /// \brief Construct a Poly1305
145 /// \param key a byte array used to key the cipher
146 /// \param keyLength the size of the byte array, in bytes
147 /// \param nonce a byte array used to key the cipher
148 /// \param nonceLength the size of the byte array, in bytes
149 /// \details The key is 32 bytes and a concatenation <tt>key = {k,s}</tt>, where
150 /// <tt>k</tt> is the AES key and <tt>r</tt> is additional key that gets clamped.
151 /// The key is clamped internally so there is no need to perform the operation
152 /// before setting the key.
153 /// \details Each message requires a unique security context. You can use GetNextIV()
154 /// and Resynchronize() to set a new nonce under a key for a message.
155 Poly1305(const byte *key, size_t keyLength=DEFAULT_KEYLENGTH, const byte *nonce=NULLPTR, size_t nonceLength=0)
156 {this->SetKey(key, keyLength, MakeParameters(Name::IV(), ConstByteArrayParameter(nonce, nonceLength)));}
157};
158
159////////////////////////////// IETF Poly1305 //////////////////////////////
160
161/// \brief Poly1305-TLS message authentication code base class
162/// \details Poly1305TLS_Base is the base class of the IETF's Poly1305 algorithm.
163/// \since Crypto++ 8.1
165{
166public:
167 static std::string StaticAlgorithmName() {return std::string("Poly1305TLS");}
168 CRYPTOPP_CONSTANT(DIGESTSIZE=16);
169 CRYPTOPP_CONSTANT(BLOCKSIZE=16);
170
171 virtual ~Poly1305TLS_Base() {}
173
174 void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
175 void Update(const byte *input, size_t length);
176 void TruncatedFinal(byte *mac, size_t size);
177 void Restart();
178
179 unsigned int BlockSize() const {return BLOCKSIZE;}
180 unsigned int DigestSize() const {return DIGESTSIZE;}
181
182protected:
183 // Accumulated hash, clamped r-key, and encrypted nonce
187
188 // Accumulated message bytes and index
190 size_t m_idx;
191};
192
193/// \brief Poly1305-TLS message authentication code
194/// \details This is the IETF's variant of Bernstein's Poly1305 from RFC 8439.
195/// IETF Poly1305 is called Poly1305TLS in the Crypto++ library. It is
196/// _slightly_ different from the Bernstein implementation. Poly1305-TLS
197/// can be used for cipher suites
198/// <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
199/// <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and
200/// <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
201/// \details The key is 32 bytes and a concatenation <tt>key = {r,s}</tt>, where
202/// <tt>r</tt> is additional key that gets clamped and <tt>s</tt> is the nonce.
203/// The key is clamped internally so there is no need to perform the operation
204/// before setting the key.
205/// \details Each message must have a unique security context, which means the key
206/// must be changed after each message. It can be accomplished in one of two ways.
207/// First, you can create a new Poly1305 object with a new key each time its needed.
208/// <pre> SecByteBlock key(32);
209/// prng.GenerateBlock(key, key.size());
210///
211/// Poly1305TLS poly1305(key, key.size());
212/// poly1305.Update(...);
213/// poly1305.Final(...);</pre>
214///
215/// \details Second, you can create a Poly1305 object, and use a new key for each
216/// message. The keys can be generated directly using a RandomNumberGenerator()
217/// derived class.
218/// <pre> SecByteBlock key(32);
219/// prng.GenerateBlock(key, key.size());
220///
221/// // First message
222/// Poly1305TLS poly1305(key, key.size());
223/// poly1305.Update(...);
224/// poly1305.Final(...);
225///
226/// // Second message
227/// prng.GenerateBlock(key, key.size());
228/// poly1305.SetKey(key, key.size());
229/// poly1305.Update(...);
230/// poly1305.Final(...);
231/// ...</pre>
232/// \warning Each message must have a unique security context. The Poly1305-TLS class
233/// does not enforce a fresh key or nonce for each message.
234/// \since Crypto++ 8.1
235/// \sa MessageAuthenticationCode(), <a href="http://tools.ietf.org/html/rfc8439">RFC
236/// 8439, ChaCha20 and Poly1305 for IETF Protocols</a>
238
239NAMESPACE_END
240
241#endif // CRYPTOPP_POLY1305_H
Classes for working with NameValuePairs.
AlgorithmParameters MakeParameters(const char *name, const T &value, bool throwIfNotUsed=true)
Create an object that implements NameValuePairs.
Definition algparam.h:508
Standard names for retrieving values by name when working with NameValuePairs.
virtual std::string AlgorithmProvider() const
Retrieve the provider of this algorithm.
Definition cryptlib.h:641
Used to pass byte array input as part of a NameValuePairs object.
Definition algparam.h:25
Inherited by keyed algorithms with fixed key length.
Definition seckey.h:125
Fixed size stack-based SecBlock with 16-byte alignment.
Definition secblock.h:1259
virtual void TruncatedFinal(byte *digest, size_t digestSize)=0
Computes the hash of the current message.
virtual void Restart()
Restart the hash.
Definition cryptlib.h:1152
virtual void Update(const byte *input, size_t length)=0
Updates a hash with additional input.
Provides class member functions to key a message authentication code.
Definition seckey.h:371
Interface for message authentication codes.
Definition cryptlib.h:1304
Interface for retrieving values given their names.
Definition cryptlib.h:327
Poly1305 message authentication code base class.
Definition poly1305.h:44
unsigned int DigestSize() const
Provides the digest size of the hash.
Definition poly1305.h:66
unsigned int BlockSize() const
Provides the block size of the compression function.
Definition poly1305.h:65
Poly1305 message authentication code.
Definition poly1305.h:137
Poly1305(const byte *key, size_t keyLength=DEFAULT_KEYLENGTH, const byte *nonce=NULL, size_t nonceLength=0)
Construct a Poly1305.
Definition poly1305.h:155
Poly1305()
Construct a Poly1305.
Definition poly1305.h:142
Poly1305-TLS message authentication code base class.
Definition poly1305.h:165
unsigned int BlockSize() const
Provides the block size of the compression function.
Definition poly1305.h:179
void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
Sets the key for this object without performing parameter validation.
Definition poly1305.cpp:315
void TruncatedFinal(byte *mac, size_t size)
Computes the hash of the current message.
Definition poly1305.cpp:374
void Update(const byte *input, size_t length)
Updates a hash with additional input.
Definition poly1305.cpp:335
unsigned int DigestSize() const
Provides the digest size of the hash.
Definition poly1305.h:180
void Restart()
Restart the hash.
Definition poly1305.cpp:394
Poly1305-TLS message authentication code.
Definition poly1305.h:237
Interface for random number generators.
Definition cryptlib.h:1440
virtual void GetNextIV(RandomNumberGenerator &rng, byte *iv)
Retrieves a secure IV for the next message.
virtual void Resynchronize(const byte *iv, int ivLength=-1)
Resynchronize with an IV.
Definition cryptlib.h:788
unsigned int word32
32-bit unsigned datatype
Definition config_int.h:72
Abstract base classes that provide a uniform interface to this library.
#define CRYPTOPP_COMPILE_ASSERT(expr)
Compile time assertion.
Definition misc.h:153
Crypto++ library namespace.
const char * IV()
ConstByteArrayParameter, also accepts const byte * for backwards compatibility.
Definition argnames.h:21
Classes and functions for secure memory allocations.
Classes and functions for implementing secret key algorithms.