# class OpenSSL::PKey::EC

`OpenSSL::PKey::EC` provides access to Elliptic Curve Digital Signature Algorithm (ECDSA) and Elliptic Curve Diffie-Hellman (ECDH).

### Key exchange¶ ↑

    ec1 = OpenSSL::PKey::EC.generate("prime256v1")
    ec2 = OpenSSL::PKey::EC.generate("prime256v1")
    # ec1 and ec2 have own private key respectively
    shared_key1 = ec1.dh_compute_key(ec2.public_key)
    shared_key2 = ec2.dh_compute_key(ec1.public_key)

    p shared_key1 == shared_key2 #=> true

### Constants

EXPLICIT_CURVE
NAMED_CURVE

### Public Class Methods

builtin_curves → [[sn, comment], ...] click to toggle source

Obtains a list of all predefined curves by the `OpenSSL`. Curve names are returned as sn.

See the `OpenSSL` documentation for EC_get_builtin_curves().

    static VALUE ossl_s_builtin_curves(VALUE self)
    {
        EC_builtin_curve *curves = NULL;
        int n;
        int crv_len = rb_long2int(EC_get_builtin_curves(NULL, 0));
        VALUE ary, ret;

        curves = ALLOCA_N(EC_builtin_curve, crv_len);
        if (curves == NULL)
            return Qnil;
        if (!EC_get_builtin_curves(curves, crv_len))
            ossl_raise(rb_eRuntimeError, "EC_get_builtin_curves");

        ret = rb_ary_new2(crv_len);

        for (n = 0; n < crv_len; n++) {
            const char *sname = OBJ_nid2sn(curves[n].nid);
            const char *comment = curves[n].comment;

            ary = rb_ary_new2(2);
            rb_ary_push(ary, rb_str_new2(sname));
            rb_ary_push(ary, comment ? rb_str_new2(comment) : Qnil);
            rb_ary_push(ret, ary);
        }

        return ret;
    }

generate(ec_group) → ec click to toggle source
generate(string) → ec

Creates a new `EC` instance with a new random private and public key.

    static VALUE
    ossl_ec_key_s_generate(VALUE klass, VALUE arg)
    {
        EC_KEY *ec;
        VALUE obj;

        ec = ec_key_new_from_group(arg);

        obj = ec_instance(klass, ec);
        if (obj == Qfalse) {
            EC_KEY_free(ec);
            ossl_raise(eECError, NULL);
        }

        if (!EC_KEY_generate_key(ec))
            ossl_raise(eECError, "EC_KEY_generate_key");

        return obj;
    }

OpenSSL::PKey::EC.new click to toggle source
OpenSSL::PKey::EC.new(ec_key)
OpenSSL::PKey::EC.new(ec_group)
OpenSSL::PKey::EC.new("secp112r1")
OpenSSL::PKey::EC.new(pem_string [, pwd])
OpenSSL::PKey::EC.new(der_string)

Creates a new `EC` object from given arguments.

    static VALUE ossl_ec_key_initialize(int argc, VALUE *argv, VALUE self)
    {
        EVP_PKEY *pkey;
        EC_KEY *ec;
        VALUE arg, pass;

        GetPKey(self, pkey);
        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_NONE)
            ossl_raise(eECError, "EC_KEY already initialized");

        rb_scan_args(argc, argv, "02", &arg, &pass);

        if (NIL_P(arg)) {
            if (!(ec = EC_KEY_new()))
                ossl_raise(eECError, NULL);
        } else if (rb_obj_is_kind_of(arg, cEC)) {
            EC_KEY *other_ec = NULL;

            GetEC(arg, other_ec);
            if (!(ec = EC_KEY_dup(other_ec)))
                ossl_raise(eECError, NULL);
        } else if (rb_obj_is_kind_of(arg, cEC_GROUP)) {
            ec = ec_key_new_from_group(arg);
        } else {
            BIO *in;

            pass = ossl_pem_passwd_value(pass);
            in = ossl_obj2bio(&arg);

            ec = PEM_read_bio_ECPrivateKey(in, NULL, ossl_pem_passwd_cb, (void *)pass);
            if (!ec) {
                OSSL_BIO_reset(in);
                ec = PEM_read_bio_EC_PUBKEY(in, NULL, ossl_pem_passwd_cb, (void *)pass);
            }
            if (!ec) {
                OSSL_BIO_reset(in);
                ec = d2i_ECPrivateKey_bio(in, NULL);
            }
            if (!ec) {
                OSSL_BIO_reset(in);
                ec = d2i_EC_PUBKEY_bio(in, NULL);
            }
            BIO_free(in);

            if (!ec) {
                ossl_clear_error();
                ec = ec_key_new_from_group(arg);
            }
        }

        if (!EVP_PKEY_assign_EC_KEY(pkey, ec)) {
            EC_KEY_free(ec);
            ossl_raise(eECError, "EVP_PKEY_assign_EC_KEY");
        }

        return self;
    }

### Public Instance Methods

check_key → true click to toggle source

Raises an exception if the key is invalid.

See the `OpenSSL` documentation for EC_KEY_check_key()

    static VALUE ossl_ec_key_check_key(VALUE self)
    {
        EC_KEY *ec;

        GetEC(self, ec);
        if (EC_KEY_check_key(ec) != 1)
            ossl_raise(eECError, "EC_KEY_check_key");

        return Qtrue;
    }

dh_compute_key(pubkey) → String click to toggle source

See the `OpenSSL` documentation for ECDH_compute_key()

    static VALUE ossl_ec_key_dh_compute_key(VALUE self, VALUE pubkey)
    {
        EC_KEY *ec;
        EC_POINT *point;
        int buf_len;
        VALUE str;

        GetEC(self, ec);
        GetECPoint(pubkey, point);

    /* BUG: need a way to figure out the maximum string size */
        buf_len = 1024;
        str = rb_str_new(0, buf_len);
    /* BUG: take KDF as a block */
        buf_len = ECDH_compute_key(RSTRING_PTR(str), buf_len, point, ec, NULL);
        if (buf_len < 0)
             ossl_raise(eECError, "ECDH_compute_key");

        rb_str_resize(str, buf_len);

        return str;
    }

dsa_sign_asn1(data) → String click to toggle source

See the `OpenSSL` documentation for ECDSA_sign()

    static VALUE ossl_ec_key_dsa_sign_asn1(VALUE self, VALUE data)
    {
        EC_KEY *ec;
        unsigned int buf_len;
        VALUE str;

        GetEC(self, ec);
        StringValue(data);

        if (EC_KEY_get0_private_key(ec) == NULL)
            ossl_raise(eECError, "Private EC key needed!");

        str = rb_str_new(0, ECDSA_size(ec));
        if (ECDSA_sign(0, (unsigned char *) RSTRING_PTR(data), RSTRING_LENINT(data), (unsigned char *) RSTRING_PTR(str), &buf_len, ec) != 1)
            ossl_raise(eECError, "ECDSA_sign");
        rb_str_set_len(str, buf_len);

        return str;
    }

dsa_verify_asn1(data, sig) → true or false click to toggle source

See the `OpenSSL` documentation for ECDSA_verify()

    static VALUE ossl_ec_key_dsa_verify_asn1(VALUE self, VALUE data, VALUE sig)
    {
        EC_KEY *ec;

        GetEC(self, ec);
        StringValue(data);
        StringValue(sig);

        switch (ECDSA_verify(0, (unsigned char *)RSTRING_PTR(data), RSTRING_LENINT(data),
                             (unsigned char *)RSTRING_PTR(sig), RSTRING_LENINT(sig), ec)) {
          case 1:
            return Qtrue;
          case 0:
            return Qfalse;
          default:
            ossl_raise(eECError, "ECDSA_verify");
        }
    }

export([cipher, pass_phrase]) → String click to toggle source
to_pem([cipher, pass_phrase]) → String

Outputs the `EC` key in PEM encoding. If cipher and pass_phrase are given they will be used to encrypt the key. cipher must be an `OpenSSL::Cipher` instance. Note that encryption will only be effective for a private key, public keys will always be encoded in plain text.

    static VALUE ossl_ec_key_export(int argc, VALUE *argv, VALUE self)
    {
        VALUE cipher, passwd;
        rb_scan_args(argc, argv, "02", &cipher, &passwd);
        return ossl_ec_key_to_string(self, cipher, passwd, EXPORT_PEM);
    }

Also aliased as: to_pem
generate_key()
Alias for: generate_key!
generate_key! → self click to toggle source

Generates a new random private and public key.

See also the `OpenSSL` documentation for EC_KEY_generate_key()

### Example¶ ↑

    ec = OpenSSL::PKey::EC.new("prime256v1")
    p ec.private_key # => nil
    ec.generate_key!
    p ec.private_key # => #<OpenSSL::BN XXXXXX>

    static VALUE ossl_ec_key_generate_key(VALUE self)
    {
        EC_KEY *ec;

        GetEC(self, ec);
        if (EC_KEY_generate_key(ec) != 1)
            ossl_raise(eECError, "EC_KEY_generate_key");

        return self;
    }

Also aliased as: generate_key
group → group click to toggle source

Returns the `EC::Group` that the key is associated with. Modifying the returned group does not affect key.

    static VALUE
    ossl_ec_key_get_group(VALUE self)
    {
        EC_KEY *ec;
        const EC_GROUP *group;

        GetEC(self, ec);
        group = EC_KEY_get0_group(ec);
        if (!group)
            return Qnil;

        return ec_group_new(group);
    }

group = group click to toggle source

Sets the `EC::Group` for the key. The group structure is internally copied so modification to group after assigning to a key has no effect on the key.

    static VALUE
    ossl_ec_key_set_group(VALUE self, VALUE group_v)
    {
        EC_KEY *ec;
        EC_GROUP *group;

        GetEC(self, ec);
        GetECGroup(group_v, group);

        if (EC_KEY_set_group(ec, group) != 1)
            ossl_raise(eECError, "EC_KEY_set_group");

        return group_v;
    }

initialize_copy(p1) click to toggle source

    static VALUE
    ossl_ec_key_initialize_copy(VALUE self, VALUE other)
    {
        EVP_PKEY *pkey;
        EC_KEY *ec, *ec_new;

        GetPKey(self, pkey);
        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_NONE)
            ossl_raise(eECError, "EC already initialized");
        GetEC(other, ec);

        ec_new = EC_KEY_dup(ec);
        if (!ec_new)
            ossl_raise(eECError, "EC_KEY_dup");
        if (!EVP_PKEY_assign_EC_KEY(pkey, ec_new)) {
            EC_KEY_free(ec_new);
            ossl_raise(eECError, "EVP_PKEY_assign_EC_KEY");
        }

        return self;
    }

private? → true or false click to toggle source

Returns whether this `EC` instance has a private key. The private key (`BN`) can be retrieved with `EC#private_key`.

    static VALUE ossl_ec_key_is_private(VALUE self)
    {
        EC_KEY *ec;

        GetEC(self, ec);

        return EC_KEY_get0_private_key(ec) ? Qtrue : Qfalse;
    }

Also aliased as: private_key?
private_key → OpenSSL::BN click to toggle source

See the `OpenSSL` documentation for EC_KEY_get0_private_key()

    static VALUE ossl_ec_key_get_private_key(VALUE self)
    {
        EC_KEY *ec;
        const BIGNUM *bn;

        GetEC(self, ec);
        if ((bn = EC_KEY_get0_private_key(ec)) == NULL)
            return Qnil;

        return ossl_bn_new(bn);
    }

private_key = openssl_bn click to toggle source

See the `OpenSSL` documentation for EC_KEY_set_private_key()

    static VALUE ossl_ec_key_set_private_key(VALUE self, VALUE private_key)
    {
        EC_KEY *ec;
        BIGNUM *bn = NULL;

        GetEC(self, ec);
        if (!NIL_P(private_key))
            bn = GetBNPtr(private_key);

        switch (EC_KEY_set_private_key(ec, bn)) {
        case 1:
            break;
        case 0:
            if (bn == NULL)
                break;
        default:
            ossl_raise(eECError, "EC_KEY_set_private_key");
        }

        return private_key;
    }

private_key?()
Alias for: private?
public? → true or false click to toggle source

Returns whether this `EC` instance has a public key. The public key (`EC::Point`) can be retrieved with `EC#public_key`.

    static VALUE ossl_ec_key_is_public(VALUE self)
    {
        EC_KEY *ec;

        GetEC(self, ec);

        return EC_KEY_get0_public_key(ec) ? Qtrue : Qfalse;
    }

Also aliased as: public_key?
public_key → OpenSSL::PKey::EC::Point click to toggle source

See the `OpenSSL` documentation for EC_KEY_get0_public_key()

    static VALUE ossl_ec_key_get_public_key(VALUE self)
    {
        EC_KEY *ec;
        const EC_POINT *point;

        GetEC(self, ec);
        if ((point = EC_KEY_get0_public_key(ec)) == NULL)
            return Qnil;

        return ec_point_new(point, EC_KEY_get0_group(ec));
    }

public_key = ec_point click to toggle source

See the `OpenSSL` documentation for EC_KEY_set_public_key()

    static VALUE ossl_ec_key_set_public_key(VALUE self, VALUE public_key)
    {
        EC_KEY *ec;
        EC_POINT *point = NULL;

        GetEC(self, ec);
        if (!NIL_P(public_key))
            GetECPoint(public_key, point);

        switch (EC_KEY_set_public_key(ec, point)) {
        case 1:
            break;
        case 0:
            if (point == NULL)
                break;
        default:
            ossl_raise(eECError, "EC_KEY_set_public_key");
        }

        return public_key;
    }

public_key?()
Alias for: public?
to_der → String click to toggle source

See the `OpenSSL` documentation for i2d_ECPrivateKey_bio()

    static VALUE ossl_ec_key_to_der(VALUE self)
    {
        return ossl_ec_key_to_string(self, Qnil, Qnil, EXPORT_DER);
    }

to_pem(p1 = v1, p2 = v2)
Alias for: export
to_text → String click to toggle source

See the `OpenSSL` documentation for EC_KEY_print()

    static VALUE ossl_ec_key_to_text(VALUE self)
    {
        EC_KEY *ec;
        BIO *out;
        VALUE str;

        GetEC(self, ec);
        if (!(out = BIO_new(BIO_s_mem()))) {
            ossl_raise(eECError, "BIO_new(BIO_s_mem())");
        }
        if (!EC_KEY_print(out, ec, 0)) {
            BIO_free(out);
            ossl_raise(eECError, "EC_KEY_print");
        }
        str = ossl_membio2str(out);

        return str;
    }