Coverage Report

Created: 2020-06-30 13:58

/src/botan/build/include/botan/chacha20poly1305.h
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/*
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* ChaCha20Poly1305 AEAD
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* (C) 2014 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_CHACHA20_POLY1305_H_
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#define BOTAN_AEAD_CHACHA20_POLY1305_H_
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#include <botan/aead.h>
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#include <botan/stream_cipher.h>
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#include <botan/mac.h>
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BOTAN_FUTURE_INTERNAL_HEADER(chacha20poly1305.h)
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namespace Botan {
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/**
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* Base class
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* See draft-irtf-cfrg-chacha20-poly1305-03 for specification
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* If a nonce of 64 bits is used the older version described in
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* draft-agl-tls-chacha20poly1305-04 is used instead.
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* If a nonce of 192 bits is used, XChaCha20Poly1305 is selected.
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*/
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class BOTAN_PUBLIC_API(2,0) ChaCha20Poly1305_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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      bool associated_data_requires_key() const override { return false; }
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      std::string name() const override { return "ChaCha20Poly1305"; }
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      size_t update_granularity() const override { return 64; }
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      Key_Length_Specification key_spec() const override
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         { return Key_Length_Specification(32); }
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      bool valid_nonce_length(size_t n) const override;
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      size_t tag_size() const override { return 16; }
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      void clear() override;
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      void reset() override;
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   protected:
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      std::unique_ptr<StreamCipher> m_chacha;
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      std::unique_ptr<MessageAuthenticationCode> m_poly1305;
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      ChaCha20Poly1305_Mode();
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      secure_vector<uint8_t> m_ad;
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      size_t m_nonce_len = 0;
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      size_t m_ctext_len = 0;
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      bool cfrg_version() const { return m_nonce_len == 12 || m_nonce_len == 24; }
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      void update_len(size_t len);
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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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   };
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/**
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* ChaCha20Poly1305 Encryption
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*/
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class BOTAN_PUBLIC_API(2,0) ChaCha20Poly1305_Encryption final : public ChaCha20Poly1305_Mode
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   {
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   public:
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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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* ChaCha20Poly1305 Decryption
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*/
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class BOTAN_PUBLIC_API(2,0) ChaCha20Poly1305_Decryption final : public ChaCha20Poly1305_Mode
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   {
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   public:
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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