Get the subject's key identifier from the subjectKeyIdentifier exteension, as described in RFC5280 Section 4.2.1.2.
Returns the binary String key identifier or nil or raises ASN1::ASN1Error.
# File openssl/lib/openssl/x509.rb, line 81 def subject_key_identifier ext = find_extension("subjectKeyIdentifier") return nil if ext.nil? ski_asn1 = ASN1.decode(ext.value_der) if ext.critical? || ski_asn1.tag_class != :UNIVERSAL || ski_asn1.tag != ASN1::OCTET_STRING raise ASN1::ASN1Error, "invalid extension" end ski_asn1.value end