Coverage Report

Created: 2020-02-14 15:38

/src/botan/build/include/botan/gcm.h
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/*
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* GCM Mode
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* (C) 2013 Jack Lloyd
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* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
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*
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* Botan is released under the Simplified BSD License (see license.txt)
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*/
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#ifndef BOTAN_AEAD_GCM_H_
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#define BOTAN_AEAD_GCM_H_
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#include <botan/aead.h>
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#include <botan/sym_algo.h>
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BOTAN_FUTURE_INTERNAL_HEADER(gcm.h)
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namespace Botan {
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class BlockCipher;
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class StreamCipher;
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class GHASH;
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/**
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* GCM Mode
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*/
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class BOTAN_PUBLIC_API(2,0) GCM_Mode : public AEAD_Mode
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   {
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   public:
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      void set_associated_data(const uint8_t ad[], size_t ad_len) override;
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      std::string name() const override;
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      size_t update_granularity() const override;
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      Key_Length_Specification key_spec() const override;
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      bool valid_nonce_length(size_t len) const override;
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      size_t tag_size() const override { return m_tag_size; }
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      void clear() override;
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      void reset() override;
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      std::string provider() const override;
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   protected:
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      GCM_Mode(BlockCipher* cipher, size_t tag_size);
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      ~GCM_Mode();
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      static const size_t GCM_BS = 16;
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      const size_t m_tag_size;
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      const std::string m_cipher_name;
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      std::unique_ptr<StreamCipher> m_ctr;
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      std::unique_ptr<GHASH> m_ghash;
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   private:
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      void start_msg(const uint8_t nonce[], size_t nonce_len) override;
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      void key_schedule(const uint8_t key[], size_t length) override;
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      secure_vector<uint8_t> m_y0;
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   };
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/**
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* GCM Encryption
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*/
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class BOTAN_PUBLIC_API(2,0) GCM_Encryption final : public GCM_Mode
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   {
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   public:
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      /**
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      * @param cipher the 128 bit block cipher to use
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      * @param tag_size is how big the auth tag will be
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      */
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      GCM_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
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         GCM_Mode(cipher, tag_size) {}
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      size_t output_length(size_t input_length) const override
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         { return input_length + tag_size(); }
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      size_t minimum_final_size() const override { return 0; }
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      size_t process(uint8_t buf[], size_t size) override;
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      void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
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   };
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/**
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* GCM Decryption
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*/
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class BOTAN_PUBLIC_API(2,0) GCM_Decryption final : public GCM_Mode
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   {
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   public:
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      /**
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      * @param cipher the 128 bit block cipher to use
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      * @param tag_size is how big the auth tag will be
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      */
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      GCM_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
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         GCM_Mode(cipher, tag_size) {}
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      size_t output_length(size_t input_length) const override
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         {
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         BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
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         return input_length - tag_size();
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         }
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      size_t minimum_final_size() const override { return tag_size(); }
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      size_t process(uint8_t buf[], size_t size) override;
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      void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
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   };
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}
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#endif