#include <ec_group.h>

Public Member Functions
SecureVector< byte >	DER_encode (EC_Group_Encoding form) const
	EC_Group (const CurveGFp &curve, const PointGFp &base_point, const BigInt &order, const BigInt &cofactor)
	EC_Group (const MemoryRegion< byte > &ber_encoding)
	EC_Group (const OID &oid)
	EC_Group (const std::string &pem_or_oid="")
const PointGFp &	get_base_point () const
const BigInt &	get_cofactor () const
const CurveGFp &	get_curve () const
std::string	get_oid () const
const BigInt &	get_order () const
bool	initialized () const
bool	operator== (const EC_Group &other) const
std::string	PEM_encode () const

Detailed Description

Class representing an elliptic curve

Definition at line 31 of file ec_group.h.

Constructor & Destructor Documentation

◆ EC_Group() [1/4]

Botan::EC_Group::EC_Group	(	const CurveGFp &	curve,
		const PointGFp &	base_point,
		const BigInt &	order,
		const BigInt &	cofactor )

inline

Construct Domain paramers from specified parameters

Parameters

curve	elliptic curve
base_point	a base point
order	the order of the base point
cofactor	the cofactor

Definition at line 42 of file ec_group.h.

                                       :
         curve(curve),
         base_point(base_point),
         order(order),
         cofactor(cofactor),
         oid("")
         {}

Referenced by EC_Group(), EC_Group(), EC_Group(), Botan::EC_PrivateKey::EC_PrivateKey(), Botan::EC_PublicKey::EC_PublicKey(), and operator==().

◆ EC_Group() [2/4]

Botan::EC_Group::EC_Group ( const MemoryRegion< byte > & ber_encoding )

Decode a BER encoded ECC domain parameter set

Parameters

ber_encoding the bytes of the BER encoding

Definition at line 51 of file ec_group.cpp.

   {
   BER_Decoder ber(ber_data);
   BER_Object obj = ber.get_next_object();
 
   if(obj.type_tag == NULL_TAG)
      throw Decoding_Error("Cannot handle ImplicitCA ECDSA parameters");
   else if(obj.type_tag == OBJECT_ID)
      {
      OID dom_par_oid;
      BER_Decoder(ber_data).decode(dom_par_oid);
      *this = EC_Group(dom_par_oid);
      }
   else if(obj.type_tag == SEQUENCE)
      {
      BigInt p, a, b;
      SecureVector<byte> sv_base_point;
 
      BER_Decoder(ber_data)
         .start_cons(SEQUENCE)
           .decode_and_check<size_t>(1, "Unknown ECC param version code")
           .start_cons(SEQUENCE)
            .decode_and_check(OID("1.2.840.10045.1.1"),
                              "Only prime ECC fields supported")
             .decode(p)
           .end_cons()
           .start_cons(SEQUENCE)
             .decode_octet_string_bigint(a)
             .decode_octet_string_bigint(b)
           .end_cons()
           .decode(sv_base_point, OCTET_STRING)
           .decode(order)
           .decode(cofactor)
         .end_cons()
         .verify_end();
 
      curve = CurveGFp(p, a, b);
      base_point = OS2ECP(sv_base_point, curve);
      }
   else
      throw Decoding_Error("Unexpected tag while decoding ECC domain params");
   }

References Botan::BER_Decoder::BER_Decoder(), Botan::CurveGFp::CurveGFp(), Botan::Decoding_Error::Decoding_Error(), EC_Group(), Botan::BER_Decoder::get_next_object(), Botan::NULL_TAG, Botan::OBJECT_ID, Botan::OCTET_STRING, Botan::OID::OID(), Botan::OS2ECP(), Botan::SEQUENCE, and Botan::BER_Object::type_tag.

◆ EC_Group() [3/4]

Botan::EC_Group::EC_Group ( const OID & oid )

Create an EC domain by OID (or throw if unknown)

Parameters

oid	the OID of the EC domain to create

Definition at line 19 of file ec_group.cpp.

   {
   std::string pem =
      global_state().get("ec", OIDS::lookup(domain_oid));
 
   if(pem == "")
      throw Lookup_Error("No ECC domain data for " + domain_oid.as_string());
 
   *this = EC_Group(pem);
   oid = domain_oid.as_string();
   }

References Botan::OID::as_string(), EC_Group(), Botan::Library_State::get(), Botan::global_state(), Botan::OIDS::lookup(), and Botan::Lookup_Error::Lookup_Error().

◆ EC_Group() [4/4]

Botan::EC_Group::EC_Group ( const std::string & pem_or_oid = "" )

Create an EC domain from PEM encoding (as from PEM_encode), or from an OID name (eg "secp160r1", or "1.3.132.0.8")

Parameters

pem_or_oid PEM-encoded data, or an OID

Definition at line 31 of file ec_group.cpp.

   {
   if(str == "")
      return; // no initialization / uninitialized
 
   try
      {
      DataSource_Memory input(str);
 
      SecureVector<byte> ber =
         PEM_Code::decode_check_label(input, "EC PARAMETERS");
 
      *this = EC_Group(ber);
      }
   catch(Decoding_Error) // hmm, not PEM?
      {
      *this = EC_Group(OIDS::lookup(str));
      }
   }

References Botan::PEM_Code::decode_check_label(), EC_Group(), and Botan::OIDS::lookup().

Member Function Documentation

◆ DER_encode()

SecureVector< byte > Botan::EC_Group::DER_encode ( EC_Group_Encoding form ) const

Create the DER encoding of this domain

Parameters

form	of encoding to use

Returns: bytes encododed as DER

Definition at line 95 of file ec_group.cpp.

   {
   if(form == EC_DOMPAR_ENC_EXPLICIT)
      {
      const size_t ecpVers1 = 1;
      OID curve_type("1.2.840.10045.1.1");
 
      const size_t p_bytes = curve.get_p().bytes();
 
      return DER_Encoder()
         .start_cons(SEQUENCE)
            .encode(ecpVers1)
            .start_cons(SEQUENCE)
               .encode(curve_type)
               .encode(curve.get_p())
            .end_cons()
            .start_cons(SEQUENCE)
               .encode(BigInt::encode_1363(curve.get_a(), p_bytes),
                       OCTET_STRING)
               .encode(BigInt::encode_1363(curve.get_b(), p_bytes),
                       OCTET_STRING)
            .end_cons()
            .encode(EC2OSP(base_point, PointGFp::UNCOMPRESSED), OCTET_STRING)
            .encode(order)
            .encode(cofactor)
         .end_cons()
         .get_contents();
      }
   else if(form == EC_DOMPAR_ENC_OID)
      return DER_Encoder().encode(OID(get_oid())).get_contents();
   else if(form == EC_DOMPAR_ENC_IMPLICITCA)
      return DER_Encoder().encode_null().get_contents();
   else
      throw Internal_Error("EC_Group::DER_encode: Unknown encoding");
   }

References Botan::EC2OSP(), Botan::EC_DOMPAR_ENC_EXPLICIT, Botan::EC_DOMPAR_ENC_IMPLICITCA, Botan::EC_DOMPAR_ENC_OID, Botan::DER_Encoder::encode(), Botan::BigInt::encode_1363(), Botan::DER_Encoder::encode_null(), Botan::DER_Encoder::end_cons(), Botan::DER_Encoder::get_contents(), get_oid(), Botan::Internal_Error::Internal_Error(), Botan::OCTET_STRING, Botan::OID::OID(), Botan::SEQUENCE, Botan::DER_Encoder::start_cons(), and Botan::PointGFp::UNCOMPRESSED.

Referenced by PEM_encode().

◆ get_base_point()

const PointGFp & Botan::EC_Group::get_base_point ( ) const

inline

Return domain parameter curve

Returns: domain parameter curve

Definition at line 95 of file ec_group.h.

95{ return base_point; }

Referenced by Botan::EC_PrivateKey::EC_PrivateKey(), Botan::EC_PrivateKey::EC_PrivateKey(), and operator==().

◆ get_cofactor()

const BigInt & Botan::EC_Group::get_cofactor ( ) const

inline

Return the cofactor

Returns: the cofactor

Definition at line 107 of file ec_group.h.

107{ return cofactor; }

Referenced by operator==().

◆ get_curve()

const CurveGFp & Botan::EC_Group::get_curve ( ) const

inline

Return domain parameter curve

Returns: domain parameter curve

Definition at line 89 of file ec_group.h.

89{ return curve; }

Referenced by operator==().

◆ get_oid()

std::string Botan::EC_Group::get_oid ( ) const

inline

Return the OID of these domain parameters

Returns: the OID

Definition at line 115 of file ec_group.h.

115{ return oid; }

Referenced by DER_encode(), and Botan::EC_PublicKey::set_parameter_encoding().

◆ get_order()

const BigInt & Botan::EC_Group::get_order ( ) const

inline

Return the order of the base point

Returns: order of the base point

Definition at line 101 of file ec_group.h.

101{ return order; }

Referenced by Botan::ECDH_KA_Operation::ECDH_KA_Operation(), and operator==().

◆ initialized()

bool Botan::EC_Group::initialized ( ) const

inline

Definition at line 109 of file ec_group.h.

109{ return !base_point.is_zero(); }

◆ operator==()

bool Botan::EC_Group::operator== ( const EC_Group & other ) const

inline

Definition at line 117 of file ec_group.h.

         {
         return ((get_curve() == other.get_curve()) &&
                 (get_base_point() == other.get_base_point()) &&
                 (get_order() == other.get_order()) &&
                 (get_cofactor() == other.get_cofactor()));
         }

References EC_Group(), get_base_point(), get_cofactor(), get_curve(), and get_order().

◆ PEM_encode()

std::string Botan::EC_Group::PEM_encode ( ) const

Return the PEM encoding (always in explicit form)

Returns: string containing PEM data

Definition at line 131 of file ec_group.cpp.

   {
   SecureVector<byte> der = DER_encode(EC_DOMPAR_ENC_EXPLICIT);
   return PEM_Code::encode(der, "EC PARAMETERS");
   }

References DER_encode(), Botan::EC_DOMPAR_ENC_EXPLICIT, and Botan::PEM_Code::encode().

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

src/pubkey/ec_group/ec_group.h
src/pubkey/ec_group/ec_group.cpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ EC_Group() [1/4]

◆ EC_Group() [2/4]

◆ EC_Group() [3/4]

◆ EC_Group() [4/4]

Member Function Documentation

◆ DER_encode()

◆ get_base_point()

◆ get_cofactor()

◆ get_curve()

◆ get_oid()

◆ get_order()

◆ initialized()

◆ operator==()

◆ PEM_encode()