fc::em::private_key Class Reference

an elliptic curve private key. More...

#include <elliptic_em.hpp>

Public Member Functions
	private_key ()
	private_key (private_key &&pk)
	private_key (const private_key &pk)
	~private_key ()
private_key &	operator= (private_key &&pk)
private_key &	operator= (const private_key &pk)
private_key	child (const fc::sha256 &offset) const
private_key_secret	get_secret () const
	operator private_key_secret () const
fc::sha512	get_shared_secret (const public_key &pub) const
compact_signature	sign_compact (const fc::sha256 &digest, bool require_canonical=true) const
public_key	get_public_key () const
unsigned int	fingerprint () const

Static Public Member Functions
static private_key	generate ()
static private_key	regenerate (const fc::sha256 &secret)
static private_key	generate_from_seed (const fc::sha256 &seed, const fc::sha256 &offset=fc::sha256())

Friends
bool	operator== (const private_key &a, const private_key &b)
bool	operator!= (const private_key &a, const private_key &b)
bool	operator< (const private_key &a, const private_key &b)

Detailed Description

Definition at line 90 of file elliptic_em.hpp.

Constructor & Destructor Documentation

private_key() [1/3]

fc::em::private_key::private_key

(

)

Definition at line 33 of file elliptic_em_impl_priv.cpp.

{}

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private_key() [2/3]

fc::em::private_key::private_key

(

private_key &&

pk

)

Definition at line 37 of file elliptic_em_impl_priv.cpp.

: my( std::move( pk.my ) ) {}

private_key() [3/3]

fc::em::private_key::private_key

(

const private_key &

pk

)

Definition at line 35 of file elliptic_em_impl_priv.cpp.

: my( pk.my ) {}

~private_key()

fc::em::private_key::~private_key

(

)

Definition at line 39 of file elliptic_em_impl_priv.cpp.

{}

Member Function Documentation

child()

private_key fc::em::private_key::child

(

const fc::sha256 &

offset

)

const

Definition at line 114 of file elliptic_em_common.cpp.

    {
       fc::sha256::encoder enc;
       fc::raw::pack( enc, get_public_key() );
       fc::raw::pack( enc, offset );
       return generate_from_seed( get_secret(), enc.result() );
    }

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fingerprint()

unsigned int fc::em::private_key::fingerprint ( ) const

inline

Definition at line 142 of file elliptic_em.hpp.

{ return get_public_key().fingerprint(); }

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generate()

private_key fc::em::private_key::generate ( )

static

Definition at line 201 of file elliptic_em_common.cpp.

    {
       EC_KEY* k = EC_KEY_new_by_curve_name( NID_secp256k1 );
       if( !k ) FC_THROW_EXCEPTION( exception, "Unable to generate EC key" );
       if( !EC_KEY_generate_key( k ) )
       {
          FC_THROW_EXCEPTION( exception, "ecc key generation error" );
 
       }
 
       return private_key( k );
    }

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generate_from_seed()

private_key fc::em::private_key::generate_from_seed ( const fc::sha256 & seed, const fc::sha256 & offset = fc::sha256() )

static

This method of generation enables creating a new private key in a deterministic manner relative to an initial seed. A public_key created from the seed can be multiplied by the offset to calculate the new public key without having to know the private key.

Definition at line 160 of file elliptic_em_common.cpp.

    {
        ssl_bignum z;
        BN_bin2bn((unsigned char*)&offset, sizeof(offset), z);
 
        ec_group group(EC_GROUP_new_by_curve_name(NID_secp256k1));
        bn_ctx ctx(BN_CTX_new());
        ssl_bignum order;
        EC_GROUP_get_order(group, order, ctx);
 
        // secexp = (seed + z) % order
        ssl_bignum secexp;
        BN_bin2bn((unsigned char*)&seed, sizeof(seed), secexp);
        BN_add(secexp, secexp, z);
        BN_mod(secexp, secexp, order, ctx);
 
        fc::sha256 secret;
        FC_ASSERT(BN_num_bytes(secexp) <= int64_t(sizeof(secret)));
        auto shift = sizeof(secret) - BN_num_bytes(secexp);
        BN_bn2bin(secexp, ((unsigned char*)&secret)+shift);
        return regenerate( secret );
    }

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get_public_key()

public_key fc::em::private_key::get_public_key

(

)

const

Definition at line 71 of file elliptic_em_impl_priv.cpp.

    {
       FC_ASSERT( my->_key != empty_priv );
       public_key_data pub;
       size_t pub_len = sizeof(pub);
       secp256k1_pubkey secp_pub;
       FC_ASSERT( secp256k1_ec_pubkey_create( detail::_get_context(), &secp_pub, (unsigned char*) my->_key.data() ) );
       secp256k1_ec_pubkey_serialize( detail::_get_context(), (unsigned char*)&pub, &pub_len, &secp_pub, SECP256K1_EC_COMPRESSED );
       FC_ASSERT( pub_len == pub.size() );
       return public_key(pub);
    }

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get_secret()

fc::sha256 fc::em::private_key::get_secret

(

)

const

Definition at line 60 of file elliptic_em_impl_priv.cpp.

    {
        return my->_key;
    }

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get_shared_secret()

fc::sha512 fc::em::private_key::get_shared_secret

(

const public_key &

pub

)

const

Given a public key, calculatse a 512 bit shared secret between that key and this private key.

Definition at line 67 of file elliptic_em.cpp.

    {
      static const private_key_secret empty_priv;
      FC_ASSERT( my->_key != empty_priv );
      FC_ASSERT( other.my->_key != empty_pub );
      secp256k1_pubkey secp_pubkey;
      FC_ASSERT( secp256k1_ec_pubkey_parse( detail::_get_context(), &secp_pubkey, (unsigned char*)other.serialize().data, other.serialize().size() ) );
      FC_ASSERT( secp256k1_ec_pubkey_tweak_mul( detail::_get_context(), &secp_pubkey, (unsigned char*) my->_key.data() ) );
      public_key_data serialized_result;
      size_t serialized_result_sz = sizeof(serialized_result);
      secp256k1_ec_pubkey_serialize(detail::_get_context(), (unsigned char*)&serialized_result.data, &serialized_result_sz, &secp_pubkey, SECP256K1_EC_COMPRESSED );
      FC_ASSERT( serialized_result_sz == sizeof(serialized_result) );
      return fc::sha512::hash( serialized_result.begin() + 1, serialized_result.size() - 1 );
    }

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operator private_key_secret()

fc::em::private_key::operator private_key_secret ( ) const

inline

Definition at line 115 of file elliptic_em.hpp.

{ return get_secret(); }

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operator=() [1/2]

private_key & fc::em::private_key::operator=

(

const private_key &

pk

)

Definition at line 47 of file elliptic_em_impl_priv.cpp.

    {
        my = pk.my;
        return *this;
    }

operator=() [2/2]

private_key & fc::em::private_key::operator=

(

private_key &&

pk

)

Definition at line 41 of file elliptic_em_impl_priv.cpp.

    {
        my = std::move( pk.my );
        return *this;
    }

regenerate()

private_key fc::em::private_key::regenerate ( const fc::sha256 & secret )

static

Definition at line 53 of file elliptic_em_impl_priv.cpp.

    {
       private_key self;
       self.my->_key = secret;
       return self;
    }

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sign_compact()

compact_signature fc::em::private_key::sign_compact	(	const fc::sha256 &	digest,
		bool	require_canonical = true ) const

Definition at line 91 of file elliptic_em_impl_priv.cpp.

    {
        FC_ASSERT( my->_key != empty_priv );
        compact_signature result;
        secp256k1_ecdsa_recoverable_signature secp_sig;
        int recid;
        unsigned int counter = 0;
        do
        {
            FC_ASSERT( secp256k1_ecdsa_sign_recoverable( detail::_get_context(), &secp_sig, (unsigned char*) digest.data(), (unsigned char*) my->_key.data(), extended_nonce_function, &counter ));
            secp256k1_ecdsa_recoverable_signature_serialize_compact( detail::_get_context(), result.data + 1, &recid, &secp_sig);
        } while( require_canonical && !public_key::is_canonical( result ) );
 
        result.begin()[0] = 27 + 4 + recid;
        return result;
    }

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Friends And Related Symbol Documentation

operator!=

bool operator!= ( const private_key & a, const private_key & b )

friend

Definition at line 133 of file elliptic_em.hpp.

           {
            return a.get_secret() != b.get_secret();
           }

operator<

bool operator< ( const private_key & a, const private_key & b )

friend

Definition at line 137 of file elliptic_em.hpp.

           {
            return a.get_secret() < b.get_secret();
           }

operator==

bool operator== ( const private_key & a, const private_key & b )

friend

Definition at line 129 of file elliptic_em.hpp.

           {
            return a.get_secret() == b.get_secret();
           }

---

The documentation for this class was generated from the following files:

• libraries/fc/include/fc/crypto/elliptic_em.hpp
• libraries/fc/src/crypto/elliptic_em.cpp
• libraries/fc/src/crypto/elliptic_em_common.cpp
• libraries/fc/src/crypto/elliptic_em_impl_priv.cpp