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125 lines
3.9 KiB
C++
125 lines
3.9 KiB
C++
#ifndef ED25519_H__
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#define ED25519_H__
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#include <memory>
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#include <openssl/bn.h>
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namespace i2p
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{
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namespace crypto
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{
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struct EDDSAPoint
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{
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BIGNUM * x {nullptr};
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BIGNUM * y {nullptr};
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BIGNUM * z {nullptr};
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BIGNUM * t {nullptr}; // projective coordinates
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EDDSAPoint () {}
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EDDSAPoint (const EDDSAPoint& other) { *this = other; }
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EDDSAPoint (EDDSAPoint&& other) { *this = std::move (other); }
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EDDSAPoint (BIGNUM * x1, BIGNUM * y1, BIGNUM * z1 = nullptr, BIGNUM * t1 = nullptr)
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: x(x1)
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, y(y1)
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, z(z1)
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, t(t1)
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{}
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~EDDSAPoint () { BN_free (x); BN_free (y); BN_free(z); BN_free(t); }
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EDDSAPoint& operator=(EDDSAPoint&& other)
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{
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if (this != &other)
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{
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BN_free (x); x = other.x; other.x = nullptr;
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BN_free (y); y = other.y; other.y = nullptr;
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BN_free (z); z = other.z; other.z = nullptr;
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BN_free (t); t = other.t; other.t = nullptr;
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}
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return *this;
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}
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EDDSAPoint& operator=(const EDDSAPoint& other)
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{
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if (this != &other)
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{
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BN_free (x); x = other.x ? BN_dup (other.x) : nullptr;
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BN_free (y); y = other.y ? BN_dup (other.y) : nullptr;
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BN_free (z); z = other.z ? BN_dup (other.z) : nullptr;
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BN_free (t); t = other.t ? BN_dup (other.t) : nullptr;
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}
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return *this;
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}
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EDDSAPoint operator-() const
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{
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BIGNUM * x1 = NULL, * y1 = NULL, * z1 = NULL, * t1 = NULL;
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if (x) { x1 = BN_dup (x); BN_set_negative (x1, !BN_is_negative (x)); };
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if (y) y1 = BN_dup (y);
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if (z) z1 = BN_dup (z);
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if (t) { t1 = BN_dup (t); BN_set_negative (t1, !BN_is_negative (t)); };
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return EDDSAPoint {x1, y1, z1, t1};
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}
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};
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const size_t EDDSA25519_PUBLIC_KEY_LENGTH = 32;
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const size_t EDDSA25519_SIGNATURE_LENGTH = 64;
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const size_t EDDSA25519_PRIVATE_KEY_LENGTH = 32;
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class Ed25519
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{
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public:
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Ed25519 ();
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Ed25519 (const Ed25519& other);
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~Ed25519 ();
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EDDSAPoint GeneratePublicKey (const uint8_t * expandedPrivateKey, BN_CTX * ctx) const;
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EDDSAPoint DecodePublicKey (const uint8_t * buf, BN_CTX * ctx) const;
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void EncodePublicKey (const EDDSAPoint& publicKey, uint8_t * buf, BN_CTX * ctx) const;
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void ScalarMul (const uint8_t * p, const uint8_t * e, uint8_t * buf, BN_CTX * ctx) const; // p is point, e is number for x25519
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void ScalarMulB (const uint8_t * e, uint8_t * buf, BN_CTX * ctx) const;
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bool Verify (const EDDSAPoint& publicKey, const uint8_t * digest, const uint8_t * signature) const;
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void Sign (const uint8_t * expandedPrivateKey, const uint8_t * publicKeyEncoded, const uint8_t * buf, size_t len, uint8_t * signature) const;
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static void ExpandPrivateKey (const uint8_t * key, uint8_t * expandedKey); // key - 32 bytes, expandedKey - 64 bytes
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private:
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EDDSAPoint Sum (const EDDSAPoint& p1, const EDDSAPoint& p2, BN_CTX * ctx) const;
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void Double (EDDSAPoint& p, BN_CTX * ctx) const;
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EDDSAPoint Mul (const EDDSAPoint& p, const BIGNUM * e, BN_CTX * ctx) const;
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EDDSAPoint MulB (const uint8_t * e, BN_CTX * ctx) const; // B*e, e is 32 bytes Little Endian
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EDDSAPoint Normalize (const EDDSAPoint& p, BN_CTX * ctx) const;
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bool IsOnCurve (const EDDSAPoint& p, BN_CTX * ctx) const;
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BIGNUM * RecoverX (const BIGNUM * y, BN_CTX * ctx) const;
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EDDSAPoint DecodePoint (const uint8_t * buf, BN_CTX * ctx) const;
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void EncodePoint (const EDDSAPoint& p, uint8_t * buf) const;
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template<int len>
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BIGNUM * DecodeBN (const uint8_t * buf) const;
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void EncodeBN (const BIGNUM * bn, uint8_t * buf, size_t len) const;
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// for x25519
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BIGNUM * ScalarMul (const BIGNUM * p, const BIGNUM * e, BN_CTX * ctx) const;
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private:
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BIGNUM * q, * l, * d, * I;
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// transient values
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BIGNUM * two_252_2; // 2^252-2
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EDDSAPoint Bi256[32][128]; // per byte, Bi256[i][j] = (256+j+1)^i*B, we don't store zeroes
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// if j > 128 we use 256 - j and carry 1 to next byte
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// Bi256[0][0] = B, base point
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EDDSAPoint Bi256Carry; // Bi256[32][0]
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};
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std::unique_ptr<Ed25519>& GetEd25519 ();
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}
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}
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#endif
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