Coverage Report

Created: 2020-06-30 13:58

/src/botan/build/include/botan/blinding.h
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/*
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* Blinding for public key operations
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* (C) 1999-2010,2015 Jack Lloyd
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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_BLINDER_H_
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#define BOTAN_BLINDER_H_
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#include <botan/bigint.h>
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#include <botan/reducer.h>
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#include <functional>
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BOTAN_FUTURE_INTERNAL_HEADER(blinding.h)
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namespace Botan {
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class RandomNumberGenerator;
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/**
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* Blinding Function Object.
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*/
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class BOTAN_PUBLIC_API(2,0) Blinder final
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   {
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   public:
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      /**
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      * Blind a value.
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      * The blinding nonce k is freshly generated after
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      * BOTAN_BLINDING_REINIT_INTERVAL calls to blind().
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      * BOTAN_BLINDING_REINIT_INTERVAL = 0 means a fresh
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      * nonce is only generated once. On every other call,
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      * an updated nonce is used for blinding: k' = k*k mod n.
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      * @param x value to blind
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      * @return blinded value
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      */
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      BigInt blind(const BigInt& x) const;
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      /**
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      * Unblind a value.
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      * @param x value to unblind
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      * @return unblinded value
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      */
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      BigInt unblind(const BigInt& x) const;
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      /**
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      * @param modulus the modulus
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      * @param rng the RNG to use for generating the nonce
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      * @param fwd_func a function that calculates the modular
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      * exponentiation of the public exponent and the given value (the nonce)
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      * @param inv_func a function that calculates the modular inverse
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      * of the given value (the nonce)
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      */
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      Blinder(const BigInt& modulus,
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              RandomNumberGenerator& rng,
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              std::function<BigInt (const BigInt&)> fwd_func,
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              std::function<BigInt (const BigInt&)> inv_func);
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      Blinder(const Blinder&) = delete;
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      Blinder& operator=(const Blinder&) = delete;
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      RandomNumberGenerator& rng() const { return m_rng; }
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   private:
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      BigInt blinding_nonce() const;
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      Modular_Reducer m_reducer;
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      RandomNumberGenerator& m_rng;
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      std::function<BigInt (const BigInt&)> m_fwd_fn;
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      std::function<BigInt (const BigInt&)> m_inv_fn;
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      size_t m_modulus_bits = 0;
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      mutable BigInt m_e, m_d;
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      mutable size_t m_counter = 0;
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   };
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}
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#endif