class OpenSSL::ASN1::Constructive

The parent class for all constructed encodings. The value attribute of a Constructive is always an Array. Attributes are the same as for ASN1Data, with the addition of tagging.


Most constructed encodings come in the form of a SET or a SEQUENCE. These encodings are represented by one of the two sub-classes of Constructive:

Please note that tagged sequences and sets are still parsed as instances of ASN1Data. Find further details on tagged values there.

Example - constructing a SEQUENCE

int =
str ='abc')
sequence = [ int, str ] )

Example - constructing a SET

int =
str ='abc')
set = [ int, str ] )



May be used as a hint for encoding a value either implicitly or explicitly by setting it either to :IMPLICIT or to :EXPLICIT. tagging is not set when a ASN.1 structure is parsed using OpenSSL::ASN1.decode.

Public Class Methods [, tag, tagging, tag_class ]) → Primitive click to toggle source

value: is mandatory.

tag: optional, may be specified for tagged values. If no tag is specified, the UNIVERSAL tag corresponding to the Primitive sub-class is used by default.

tagging: may be used as an encoding hint to encode a value either explicitly or implicitly, see ASN1 for possible values.

tag_class: if tag and tagging are nil then this is set to :UNIVERSAL by default. If either tag or tagging are set then :CONTEXT_SPECIFIC is used as the default. For possible values please cf. ASN1.


int =
zero_tagged_int =, 0, :IMPLICIT)
private_explicit_zero_tagged_int =, 0, :EXPLICIT, :PRIVATE)
static VALUE
ossl_asn1_initialize(int argc, VALUE *argv, VALUE self)
    VALUE value, tag, tagging, tag_class;
    int default_tag;

    rb_scan_args(argc, argv, "13", &value, &tag, &tagging, &tag_class);
    default_tag = ossl_asn1_default_tag(self);

    if (default_tag == -1 || argc > 1) {
            ossl_raise(eASN1Error, "must specify tag number");
        if(!NIL_P(tagging) && !SYMBOL_P(tagging))
            ossl_raise(eASN1Error, "invalid tagging method");
        if(NIL_P(tag_class)) {
            if (NIL_P(tagging))
                tag_class = sym_UNIVERSAL;
                tag_class = sym_CONTEXT_SPECIFIC;
            ossl_raise(eASN1Error, "invalid tag class");
        tag = INT2NUM(default_tag);
        tagging = Qnil;
        tag_class = sym_UNIVERSAL;
    ossl_asn1_set_tag(self, tag);
    ossl_asn1_set_value(self, value);
    ossl_asn1_set_tagging(self, tagging);
    ossl_asn1_set_tag_class(self, tag_class);
    ossl_asn1_set_indefinite_length(self, Qfalse);
    if (default_tag == V_ASN1_BIT_STRING)
        rb_ivar_set(self, sivUNUSED_BITS, INT2FIX(0));

    return self;

Public Instance Methods

each { |asn1| block } → asn1_ary click to toggle source

Calls the given block once for each element in self, passing that element as parameter asn1. If no block is given, an enumerator is returned instead.


asn1_ary.each do |asn1|
  puts asn1
static VALUE
ossl_asn1cons_each(VALUE self)
    rb_block_call(ossl_asn1_get_value(self), id_each, 0, 0, 0, 0);

    return self;
to_der → DER-encoded String click to toggle source

See OpenSSL::ASN1::ASN1Data#to_der for details.

static VALUE
ossl_asn1cons_to_der(VALUE self)
    VALUE ary, str;
    long i;
    int indef_len;

    indef_len = RTEST(ossl_asn1_get_indefinite_length(self));
    ary = rb_convert_type(ossl_asn1_get_value(self), T_ARRAY, "Array", "to_a");
    str = rb_str_new(NULL, 0);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
        VALUE item = RARRAY_AREF(ary, i);

        if (indef_len && rb_obj_is_kind_of(item, cASN1EndOfContent)) {
            if (i != RARRAY_LEN(ary) - 1)
                ossl_raise(eASN1Error, "illegal EOC octets in value");

             * EOC is not really part of the content, but we required to add one
             * at the end in the past.

        item = ossl_to_der_if_possible(item);
        rb_str_append(str, item);

    return to_der_internal(self, 1, indef_len, str);