Module: PQCrypto::SPKI

Defined in:
lib/pq_crypto/spki.rb

Constant Summary collapse

PEM_LABEL = 
"PUBLIC KEY"
PEM_BEGIN = 
"-----BEGIN #{PEM_LABEL}-----"
PEM_END = 
"-----END #{PEM_LABEL}-----"

Class Method Summary collapse

Class Method Details

.decode_der(der) ⇒ Object 



39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
 
# File 'lib/pq_crypto/spki.rb', line 39

def decode_der(der)
  input = String(der).b
  outer = decode_asn1(input)
  raise SerializationError, "SPKI DER contains trailing data" unless outer.to_der.b == input
  raise SerializationError, "SPKI must be an ASN.1 SEQUENCE" unless outer.is_a?(OpenSSL::ASN1::Sequence)
  raise SerializationError, "SPKI SEQUENCE must contain exactly 2 elements" unless outer.value.size == 2

  algorithm_identifier, subject_public_key = outer.value
  algorithm = decode_algorithm_identifier(algorithm_identifier)
  entry = AlgorithmRegistry.fetch(algorithm)
  validate_public_key_algorithm!(algorithm, entry)

  unless subject_public_key.is_a?(OpenSSL::ASN1::BitString)
    raise SerializationError, "SPKI subjectPublicKey must be a BIT STRING"
  end
  unless subject_public_key.unused_bits.zero?
    raise SerializationError, "SPKI subjectPublicKey must have zero unused bits"
  end

  bytes = String(subject_public_key.value).b
  expected = entry.fetch(:public_key_bytes)
  unless bytes.bytesize == expected
    raise SerializationError,
          "Invalid #{algorithm.inspect} SPKI public key length: expected #{expected}, got #{bytes.bytesize}"
  end

  [algorithm, bytes]
rescue OpenSSL::OpenSSLError, TypeError => e
  raise SerializationError, e.message
end

.decode_pem(pem) ⇒ Object 



70
71
72
73
 
# File 'lib/pq_crypto/spki.rb', line 70

def decode_pem(pem)
  der = der_from_pem(pem)
  decode_der(der)
end

.encode_der(algorithm_symbol, public_key_bytes) ⇒ Object 



12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
# File 'lib/pq_crypto/spki.rb', line 12

def encode_der(algorithm_symbol, public_key_bytes)
  entry = AlgorithmRegistry.fetch(algorithm_symbol)
  validate_public_key_algorithm!(algorithm_symbol, entry)

  bytes = String(public_key_bytes).b
  expected = entry.fetch(:public_key_bytes)
  unless bytes.bytesize == expected
    raise SerializationError,
          "Invalid #{algorithm_symbol.inspect} public key length: expected #{expected}, got #{bytes.bytesize}"
  end

  OpenSSL::ASN1::Sequence.new([
    OpenSSL::ASN1::Sequence.new([
      OpenSSL::ASN1::ObjectId.new(AlgorithmRegistry.standard_oid(algorithm_symbol)),
    ]),
    OpenSSL::ASN1::BitString.new(bytes),
  ]).to_der.b
rescue OpenSSL::OpenSSLError, TypeError => e
  raise SerializationError, e.message
end

.encode_pem(algorithm_symbol, public_key_bytes) ⇒ Object 



33
34
35
36
37
 
# File 'lib/pq_crypto/spki.rb', line 33

def encode_pem(algorithm_symbol, public_key_bytes)
  der = encode_der(algorithm_symbol, public_key_bytes)
  body = encode_base64(der).scan(/.{1,64}/).join("\n")
  "#{PEM_BEGIN}\n#{body}\n#{PEM_END}\n"
end