/src/botan/build/include/public/botan/stream_cipher.h

Source (jump to first uncovered line)
/*
* Stream Cipher
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_STREAM_CIPHER_H_
#define BOTAN_STREAM_CIPHER_H_

#include <botan/concepts.h>
#include <botan/secmem.h>
#include <botan/sym_algo.h>
#include <memory>
#include <string>
#include <string_view>
#include <vector>

namespace Botan {

/**
* Base class for all stream ciphers
*/
class BOTAN_PUBLIC_API(2, 0) StreamCipher : public SymmetricAlgorithm {
   public:
      ~StreamCipher() override = default;

      /**
      * Create an instance based on a name
      * If provider is empty then best available is chosen.
      * @param algo_spec algorithm name
      * @param provider provider implementation to use
      * @return a null pointer if the algo/provider combination cannot be found
      */
      static std::unique_ptr<StreamCipher> create(std::string_view algo_spec, std::string_view provider = "");

      /**
      * Create an instance based on a name
      * If provider is empty then best available is chosen.
      * @param algo_spec algorithm name
      * @param provider provider implementation to use
      * Throws a Lookup_Error if the algo/provider combination cannot be found
      */
      static std::unique_ptr<StreamCipher> create_or_throw(std::string_view algo_spec, std::string_view provider = "");

      /**
      * @return list of available providers for this algorithm, empty if not available
      */
      static std::vector<std::string> providers(std::string_view algo_spec);

      /**
      * Encrypt or decrypt a message
      *
      * Processes all bytes plain/ciphertext from @p in and writes the result to
      * @p out.
      *
      * @param in the plaintext
      * @param out the byte array to hold the output, i.e. the ciphertext
      * @param len the length of both in and out in bytes
      */
      void cipher(const uint8_t in[], uint8_t out[], size_t len) { cipher_bytes(in, out, len); }

      /**
      * Encrypt or decrypt a message
      * @param in the plaintext
      * @param out the byte array to hold the output, i.e. the ciphertext
      *            with at least the same size as @p in
      */
      void cipher(std::span<const uint8_t> in, std::span<uint8_t> out);

      /**
      * Write keystream bytes to a buffer
      *
      * The contents of @p out are ignored/overwritten
      *
      * @param out the byte array to hold the keystream
      * @param len the length of out in bytes
      */
      void write_keystream(uint8_t out[], size_t len) { generate_keystream(out, len); }

      /**
      * Fill a given buffer with keystream bytes
      *
      * The contents of @p out are ignored/overwritten
      *
      * @param out the byte array to hold the keystream
      */
      void write_keystream(std::span<uint8_t> out) { generate_keystream(out.data(), out.size()); }

      /**
      * Get @p bytes from the keystream
      *
      * The bytes are written into a continous byte buffer of your choosing.
      *
      * @param bytes The number of bytes to be produced
      */
      template <concepts::resizable_byte_buffer T = secure_vector<uint8_t>>
      T keystream_bytes(size_t bytes) {
         T out(bytes);
         write_keystream(out);
         return out;
      }

      /**
      * Encrypt or decrypt a message
      * The message is encrypted/decrypted in place.
      * @param buf the plaintext / ciphertext
      * @param len the length of buf in bytes
      */
      void cipher1(uint8_t buf[], size_t len) { cipher(buf, buf, len); }

      /**
      * Encrypt or decrypt a message
      * The message is encrypted/decrypted in place.
      * @param buf the plaintext / ciphertext
      */
      void cipher1(std::span<uint8_t> buf) { cipher(buf, buf); }

      /**
      * Encrypt a message
      * The message is encrypted/decrypted in place.
      * @param inout the plaintext / ciphertext
      */
      void encipher(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }

      /**
      * Encrypt a message
      * The message is encrypted in place.
      * @param inout the plaintext / ciphertext
      */
      void encrypt(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }

      /**
      * Decrypt a message in place
      * The message is decrypted in place.
      * @param inout the plaintext / ciphertext
      */
      void decrypt(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }

      /**
      * Return the optimium buffer size to use with this cipher
      *
      * Most stream ciphers internally produce blocks of bytes.  This function
      * returns that block size. Aligning buffer sizes to a multiple of this
      * size may improve performance by reducing internal buffering overhead.
      *
      * Note the return value of this function may change for any particular
      * algorithm due to changes in the implementation from release to release,
      * or changes in the runtime environment (such as CPUID indicating
      * availability of an optimized implementation). It is not intrinsic to
      * the algorithm; it is just a suggestion for gaining best performance.
      */
      virtual size_t buffer_size() const = 0;

      /**
      * Resync the cipher using the IV
      *
      * Load @p IV into the stream cipher state. This should happen after the
      * key is set (set_key()) and before any operation (encrypt(), decrypt() or
      * seek()) is called.
      *
      * If the cipher does not support IVs, then a call with an empty IV will be
      * accepted and any other length will cause an Invalid_IV_Length exception.
      *
      * @param iv the initialization vector
      * @param iv_len the length of the IV in bytes
      */
      void set_iv(const uint8_t iv[], size_t iv_len) { set_iv_bytes(iv, iv_len); }

      /**
      * Resync the cipher using the IV
      * @param iv the initialization vector
      * @throws Invalid_IV_Length if an incompatible IV was passed.
      */
      void set_iv(std::span<const uint8_t> iv) { set_iv_bytes(iv.data(), iv.size()); }

      /**
      * Return the default (preferred) nonce length
      *
      * If this function returns zero, then this cipher does not support nonces;
      * in this case any call to set_iv with a (non-empty) value will fail.
      *
      * Default implementation returns 0
      */
      virtual size_t default_iv_length() const;

      /**
      * @param iv_len the length of the IV in bytes
      * @return if the length is valid for this algorithm
      */
      virtual bool valid_iv_length(size_t iv_len) const { return (iv_len == 0); }

      /**
      * @return a new object representing the same algorithm as *this
      */
      StreamCipher* clone() const { return this->new_object().release(); }

      /**
      * @return new object representing the same algorithm as *this
      */
      virtual std::unique_ptr<StreamCipher> new_object() const = 0;

      /**
      * Set the offset and the state used later to generate the keystream
      *
      * Sets the state of the stream cipher and keystream according to the
      * passed @p offset, exactly as if @p offset bytes had first been
      * encrypted. The key and (if required) the IV have to be set before this
      * can be called.
      *
      * @note Not all ciphers support seeking; such objects will throw
      *       Not_Implemented in this case.
      *
      * @param offset the offset where we begin to generate the keystream
      */
      virtual void seek(uint64_t offset) = 0;

      /**
      * @return provider information about this implementation. Default is "base",
      * might also return "sse2", "avx2" or some other arbitrary string.
      */
      virtual std::string provider() const { return "base"; }

   protected:
      /**
      * Encrypt or decrypt a message
      */
      virtual void cipher_bytes(const uint8_t in[], uint8_t out[], size_t len) = 0;

      /**
      * Write keystream bytes to a buffer
      */
      virtual void generate_keystream(uint8_t out[], size_t len);

      /**
      * Resync the cipher using the IV
      */
      virtual void set_iv_bytes(const uint8_t iv[], size_t iv_len) = 0;
};

}  // namespace Botan

#endif

Coverage Report

Created: 2025-04-24 07:09

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Stream Cipher
3		* (C) 1999-2007 Jack Lloyd
4		*
5		* Botan is released under the Simplified BSD License (see license.txt)
6		*/
7
8		#ifndef BOTAN_STREAM_CIPHER_H_
9		#define BOTAN_STREAM_CIPHER_H_
10
11		#include <botan/concepts.h>
12		#include <botan/secmem.h>
13		#include <botan/sym_algo.h>
14		#include <memory>
15		#include <string>
16		#include <string_view>
17		#include <vector>
18
19		namespace Botan {
20
21		/**
22		* Base class for all stream ciphers
23		*/
24		class BOTAN_PUBLIC_API(2, 0) StreamCipher : public SymmetricAlgorithm {
25		public:
26		~StreamCipher() override = default;
27
28		/**
29		* Create an instance based on a name
30		* If provider is empty then best available is chosen.
31		* @param algo_spec algorithm name
32		* @param provider provider implementation to use
33		* @return a null pointer if the algo/provider combination cannot be found
34		*/
35		static std::unique_ptr<StreamCipher> create(std::string_view algo_spec, std::string_view provider = "");
36
37		/**
38		* Create an instance based on a name
39		* If provider is empty then best available is chosen.
40		* @param algo_spec algorithm name
41		* @param provider provider implementation to use
42		* Throws a Lookup_Error if the algo/provider combination cannot be found
43		*/
44		static std::unique_ptr<StreamCipher> create_or_throw(std::string_view algo_spec, std::string_view provider = "");
45
46		/**
47		* @return list of available providers for this algorithm, empty if not available
48		*/
49		static std::vector<std::string> providers(std::string_view algo_spec);
50
51		/**
52		* Encrypt or decrypt a message
53		*
54		* Processes all bytes plain/ciphertext from @p in and writes the result to
55		* @p out.
56		*
57		* @param in the plaintext
58		* @param out the byte array to hold the output, i.e. the ciphertext
59		* @param len the length of both in and out in bytes
60		*/
61	0	void cipher(const uint8_t in[], uint8_t out[], size_t len) { cipher_bytes(in, out, len); }
62
63		/**
64		* Encrypt or decrypt a message
65		* @param in the plaintext
66		* @param out the byte array to hold the output, i.e. the ciphertext
67		* with at least the same size as @p in
68		*/
69		void cipher(std::span<const uint8_t> in, std::span<uint8_t> out);
70
71		/**
72		* Write keystream bytes to a buffer
73		*
74		* The contents of @p out are ignored/overwritten
75		*
76		* @param out the byte array to hold the keystream
77		* @param len the length of out in bytes
78		*/
79	0	void write_keystream(uint8_t out[], size_t len) { generate_keystream(out, len); }
80
81		/**
82		* Fill a given buffer with keystream bytes
83		*
84		* The contents of @p out are ignored/overwritten
85		*
86		* @param out the byte array to hold the keystream
87		*/
88	0	void write_keystream(std::span<uint8_t> out) { generate_keystream(out.data(), out.size()); }
89
90		/**
91		* Get @p bytes from the keystream
92		*
93		* The bytes are written into a continous byte buffer of your choosing.
94		*
95		* @param bytes The number of bytes to be produced
96		*/
97		template <concepts::resizable_byte_buffer T = secure_vector<uint8_t>>
98		T keystream_bytes(size_t bytes) {
99		T out(bytes);
100		write_keystream(out);
101		return out;
102		}
103
104		/**
105		* Encrypt or decrypt a message
106		* The message is encrypted/decrypted in place.
107		* @param buf the plaintext / ciphertext
108		* @param len the length of buf in bytes
109		*/
110	0	void cipher1(uint8_t buf[], size_t len) { cipher(buf, buf, len); }
111
112		/**
113		* Encrypt or decrypt a message
114		* The message is encrypted/decrypted in place.
115		* @param buf the plaintext / ciphertext
116		*/
117	0	void cipher1(std::span<uint8_t> buf) { cipher(buf, buf); }
118
119		/**
120		* Encrypt a message
121		* The message is encrypted/decrypted in place.
122		* @param inout the plaintext / ciphertext
123		*/
124	0	void encipher(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }
125
126		/**
127		* Encrypt a message
128		* The message is encrypted in place.
129		* @param inout the plaintext / ciphertext
130		*/
131	0	void encrypt(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }
132
133		/**
134		* Decrypt a message in place
135		* The message is decrypted in place.
136		* @param inout the plaintext / ciphertext
137		*/
138	0	void decrypt(std::span<uint8_t> inout) { cipher(inout.data(), inout.data(), inout.size()); }
139
140		/**
141		* Return the optimium buffer size to use with this cipher
142		*
143		* Most stream ciphers internally produce blocks of bytes. This function
144		* returns that block size. Aligning buffer sizes to a multiple of this
145		* size may improve performance by reducing internal buffering overhead.
146		*
147		* Note the return value of this function may change for any particular
148		* algorithm due to changes in the implementation from release to release,
149		* or changes in the runtime environment (such as CPUID indicating
150		* availability of an optimized implementation). It is not intrinsic to
151		* the algorithm; it is just a suggestion for gaining best performance.
152		*/
153		virtual size_t buffer_size() const = 0;
154
155		/**
156		* Resync the cipher using the IV
157		*
158		* Load @p IV into the stream cipher state. This should happen after the
159		* key is set (set_key()) and before any operation (encrypt(), decrypt() or
160		* seek()) is called.
161		*
162		* If the cipher does not support IVs, then a call with an empty IV will be
163		* accepted and any other length will cause an Invalid_IV_Length exception.
164		*
165		* @param iv the initialization vector
166		* @param iv_len the length of the IV in bytes
167		*/
168	0	void set_iv(const uint8_t iv[], size_t iv_len) { set_iv_bytes(iv, iv_len); }
169
170		/**
171		* Resync the cipher using the IV
172		* @param iv the initialization vector
173		* @throws Invalid_IV_Length if an incompatible IV was passed.
174		*/
175	0	void set_iv(std::span<const uint8_t> iv) { set_iv_bytes(iv.data(), iv.size()); }
176
177		/**
178		* Return the default (preferred) nonce length
179		*
180		* If this function returns zero, then this cipher does not support nonces;
181		* in this case any call to set_iv with a (non-empty) value will fail.
182		*
183		* Default implementation returns 0
184		*/
185		virtual size_t default_iv_length() const;
186
187		/**
188		* @param iv_len the length of the IV in bytes
189		* @return if the length is valid for this algorithm
190		*/
191	0	virtual bool valid_iv_length(size_t iv_len) const { return (iv_len == 0); }
192
193		/**
194		* @return a new object representing the same algorithm as *this
195		*/
196	0	StreamCipher* clone() const { return this->new_object().release(); }
197
198		/**
199		* @return new object representing the same algorithm as *this
200		*/
201		virtual std::unique_ptr<StreamCipher> new_object() const = 0;
202
203		/**
204		* Set the offset and the state used later to generate the keystream
205		*
206		* Sets the state of the stream cipher and keystream according to the
207		* passed @p offset, exactly as if @p offset bytes had first been
208		* encrypted. The key and (if required) the IV have to be set before this
209		* can be called.
210		*
211		* @note Not all ciphers support seeking; such objects will throw
212		* Not_Implemented in this case.
213		*
214		* @param offset the offset where we begin to generate the keystream
215		*/
216		virtual void seek(uint64_t offset) = 0;
217
218		/**
219		* @return provider information about this implementation. Default is "base",
220		* might also return "sse2", "avx2" or some other arbitrary string.
221		*/
222	0	virtual std::string provider() const { return "base"; }
223
224		protected:
225		/**
226		* Encrypt or decrypt a message
227		*/
228		virtual void cipher_bytes(const uint8_t in[], uint8_t out[], size_t len) = 0;
229
230		/**
231		* Write keystream bytes to a buffer
232		*/
233		virtual void generate_keystream(uint8_t out[], size_t len);
234
235		/**
236		* Resync the cipher using the IV
237		*/
238		virtual void set_iv_bytes(const uint8_t iv[], size_t iv_len) = 0;
239		};
240
241		} // namespace Botan
242
243		#endif