Rasn1
Rasn1 is a ruby ASN.1 library to encode, parse and decode ASN.1 data in DER format.
Installation
Add this line to your application's Gemfile:
gem 'rasn1'And then execute:
$ bundle install
Or install it yourself as:
$ gem install rasn1
Simple usage
To decode a DER/BER string without checking a model, do:
decoded_der = RASN1.parse(der_string)
decoded_ber = RASN1.parse(ber_string, ber: true)Advanced usage
All examples below will be based on:
Record ::= SEQUENCE {
id INTEGER,
room [0] INTEGER OPTIONAL,
house [1] INTEGER DEFAULT 0
}
ComplexRecord ::= SEQUENCE {
bool BOOLEAN,
data [0] EXPLICIT OCTET STRING,
a_record Record
}
Create a ASN.1 model
class Record < RASN1::Model
sequence :record,
content: [integer(:id),
integer(:room, implicit: 0, optional: true),
integer(:house, implicit: 1, default: 0)]
endMore comple classes may be designed by nesting simple classes. For example:
class ComplexRecord < RASN1::Model
sequence :cplx_record,
content: [boolean(:bool),
octet_string(:data, explicit: 0),
model(:a_record, Record)]
endParse a DER-encoded string
record = Record.parse(der_string)
record[:id] # => RASN1::Types::Integer
record[:id].value # => Integer
record[:id].to_i # => Integer
record[:id].asn1_class # => Symbol
record[:id].optional? # => false
record[:id].default # => nil
record[:room].optional # => true
record[:house].default # => 0
record[:id].to_der # => String
cplx_record = ComplexRecord.parse(der_string)
cplx_record[:bool] # => RASN1::Types::Boolean
cplx_record[:bool].value # => TrueClass/FalseClass
cplx_record[:data].value # => String
cplx_record[:data].explicit? # => true
cplx_record[:a_record] # => RecordGenerate a DER-encoded string
record = Record.new(id: 12)
record[:id].to_i # => 12
record[:room] # => nil
record[:house] # => 0
# Set one value
record[:room] = 43
record[:room] # => 43
# Set mulitple values
record.set id: 124, house: 155
record.to_der # => StringMore information
see https://github.com/sdaubert/rasn1/wiki
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/sdaubert/rasn1.