-- |
-- Module      : Data.X509.AlgorithmIdentifier
-- License     : BSD-style
-- Maintainer  : Vincent Hanquez <vincent@snarc.org>
-- Stability   : experimental
-- Portability : unknown
module Data.X509.AlgorithmIdentifier (
    HashALG (..),
    PubKeyALG (..),
    SignatureALG (..),
) where

import Data.ASN1.Types
import Data.List (find)

-- | Hash Algorithm
data HashALG
    = HashMD2
    | HashMD5
    | HashSHA1
    | HashSHA224
    | HashSHA256
    | HashSHA384
    | HashSHA512
    deriving (Int -> HashALG -> ShowS
[HashALG] -> ShowS
HashALG -> String
(Int -> HashALG -> ShowS)
-> (HashALG -> String) -> ([HashALG] -> ShowS) -> Show HashALG
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Int -> HashALG -> ShowS
showsPrec :: Int -> HashALG -> ShowS
$cshow :: HashALG -> String
show :: HashALG -> String
$cshowList :: [HashALG] -> ShowS
showList :: [HashALG] -> ShowS
Show, HashALG -> HashALG -> Bool
(HashALG -> HashALG -> Bool)
-> (HashALG -> HashALG -> Bool) -> Eq HashALG
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: HashALG -> HashALG -> Bool
== :: HashALG -> HashALG -> Bool
$c/= :: HashALG -> HashALG -> Bool
/= :: HashALG -> HashALG -> Bool
Eq)

-- | Public Key Algorithm
data PubKeyALG
    = -- | RSA Public Key algorithm
      PubKeyALG_RSA
    | -- | RSA PSS Key algorithm (RFC 3447)
      PubKeyALG_RSAPSS
    | -- | DSA Public Key algorithm
      PubKeyALG_DSA
    | -- | ECDSA & ECDH Public Key algorithm
      PubKeyALG_EC
    | -- | ECDH 25519 key agreement
      PubKeyALG_X25519
    | -- | ECDH 448 key agreement
      PubKeyALG_X448
    | -- | EdDSA 25519 signature algorithm
      PubKeyALG_Ed25519
    | -- | EdDSA 448 signature algorithm
      PubKeyALG_Ed448
    | -- | Diffie Hellman Public Key algorithm
      PubKeyALG_DH
    | -- | Unknown Public Key algorithm
      PubKeyALG_Unknown OID
    deriving (Int -> PubKeyALG -> ShowS
[PubKeyALG] -> ShowS
PubKeyALG -> String
(Int -> PubKeyALG -> ShowS)
-> (PubKeyALG -> String)
-> ([PubKeyALG] -> ShowS)
-> Show PubKeyALG
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Int -> PubKeyALG -> ShowS
showsPrec :: Int -> PubKeyALG -> ShowS
$cshow :: PubKeyALG -> String
show :: PubKeyALG -> String
$cshowList :: [PubKeyALG] -> ShowS
showList :: [PubKeyALG] -> ShowS
Show, PubKeyALG -> PubKeyALG -> Bool
(PubKeyALG -> PubKeyALG -> Bool)
-> (PubKeyALG -> PubKeyALG -> Bool) -> Eq PubKeyALG
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: PubKeyALG -> PubKeyALG -> Bool
== :: PubKeyALG -> PubKeyALG -> Bool
$c/= :: PubKeyALG -> PubKeyALG -> Bool
/= :: PubKeyALG -> PubKeyALG -> Bool
Eq)

-- | Signature Algorithm, often composed of a public key algorithm and a hash
-- algorithm.  For some signature algorithms the hash algorithm is intrinsic to
-- the public key algorithm and is not needed in the data type.
data SignatureALG
    = SignatureALG HashALG PubKeyALG
    | SignatureALG_IntrinsicHash PubKeyALG
    | SignatureALG_Unknown OID
    deriving (Int -> SignatureALG -> ShowS
[SignatureALG] -> ShowS
SignatureALG -> String
(Int -> SignatureALG -> ShowS)
-> (SignatureALG -> String)
-> ([SignatureALG] -> ShowS)
-> Show SignatureALG
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Int -> SignatureALG -> ShowS
showsPrec :: Int -> SignatureALG -> ShowS
$cshow :: SignatureALG -> String
show :: SignatureALG -> String
$cshowList :: [SignatureALG] -> ShowS
showList :: [SignatureALG] -> ShowS
Show, SignatureALG -> SignatureALG -> Bool
(SignatureALG -> SignatureALG -> Bool)
-> (SignatureALG -> SignatureALG -> Bool) -> Eq SignatureALG
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: SignatureALG -> SignatureALG -> Bool
== :: SignatureALG -> SignatureALG -> Bool
$c/= :: SignatureALG -> SignatureALG -> Bool
/= :: SignatureALG -> SignatureALG -> Bool
Eq)

instance OIDable PubKeyALG where
    getObjectID :: PubKeyALG -> OID
getObjectID PubKeyALG
PubKeyALG_RSA = [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
1]
    getObjectID PubKeyALG
PubKeyALG_RSAPSS = [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
10]
    getObjectID PubKeyALG
PubKeyALG_DSA = [Integer
1, Integer
2, Integer
840, Integer
10040, Integer
4, Integer
1]
    getObjectID PubKeyALG
PubKeyALG_EC = [Integer
1, Integer
2, Integer
840, Integer
10045, Integer
2, Integer
1]
    getObjectID PubKeyALG
PubKeyALG_X25519 = [Integer
1, Integer
3, Integer
101, Integer
110]
    getObjectID PubKeyALG
PubKeyALG_X448 = [Integer
1, Integer
3, Integer
101, Integer
111]
    getObjectID PubKeyALG
PubKeyALG_Ed25519 = [Integer
1, Integer
3, Integer
101, Integer
112]
    getObjectID PubKeyALG
PubKeyALG_Ed448 = [Integer
1, Integer
3, Integer
101, Integer
113]
    getObjectID PubKeyALG
PubKeyALG_DH = [Integer
1, Integer
2, Integer
840, Integer
10046, Integer
2, Integer
1]
    getObjectID (PubKeyALG_Unknown OID
oid) = OID
oid

sig_table :: [(OID, SignatureALG)]
sig_table :: [(OID, SignatureALG)]
sig_table =
    [ ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
5], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA1 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
4], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashMD5 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
2], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashMD2 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
11], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA256 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
12], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA384 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
13], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA512 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
14], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA224 PubKeyALG
PubKeyALG_RSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
10040, Integer
4, Integer
3], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA1 PubKeyALG
PubKeyALG_DSA)
    , ([Integer
1, Integer
2, Integer
840, Integer
10045, Integer
4, Integer
1], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA1 PubKeyALG
PubKeyALG_EC)
    , ([Integer
1, Integer
2, Integer
840, Integer
10045, Integer
4, Integer
3, Integer
1], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA224 PubKeyALG
PubKeyALG_EC)
    , ([Integer
1, Integer
2, Integer
840, Integer
10045, Integer
4, Integer
3, Integer
2], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA256 PubKeyALG
PubKeyALG_EC)
    , ([Integer
1, Integer
2, Integer
840, Integer
10045, Integer
4, Integer
3, Integer
3], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA384 PubKeyALG
PubKeyALG_EC)
    , ([Integer
1, Integer
2, Integer
840, Integer
10045, Integer
4, Integer
3, Integer
4], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA512 PubKeyALG
PubKeyALG_EC)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
2, Integer
1], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA256 PubKeyALG
PubKeyALG_RSAPSS)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
2, Integer
2], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA384 PubKeyALG
PubKeyALG_RSAPSS)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
2, Integer
3], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA512 PubKeyALG
PubKeyALG_RSAPSS)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
2, Integer
4], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA224 PubKeyALG
PubKeyALG_RSAPSS)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
3, Integer
1], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA224 PubKeyALG
PubKeyALG_DSA)
    , ([Integer
2, Integer
16, Integer
840, Integer
1, Integer
101, Integer
3, Integer
4, Integer
3, Integer
2], HashALG -> PubKeyALG -> SignatureALG
SignatureALG HashALG
HashSHA256 PubKeyALG
PubKeyALG_DSA)
    , ([Integer
1, Integer
3, Integer
101, Integer
112], PubKeyALG -> SignatureALG
SignatureALG_IntrinsicHash PubKeyALG
PubKeyALG_Ed25519)
    , ([Integer
1, Integer
3, Integer
101, Integer
113], PubKeyALG -> SignatureALG
SignatureALG_IntrinsicHash PubKeyALG
PubKeyALG_Ed448)
    ]

oidSig :: OID -> SignatureALG
oidSig :: OID -> SignatureALG
oidSig OID
oid = SignatureALG
-> (SignatureALG -> SignatureALG)
-> Maybe SignatureALG
-> SignatureALG
forall b a. b -> (a -> b) -> Maybe a -> b
maybe (OID -> SignatureALG
SignatureALG_Unknown OID
oid) SignatureALG -> SignatureALG
forall a. a -> a
id (Maybe SignatureALG -> SignatureALG)
-> Maybe SignatureALG -> SignatureALG
forall a b. (a -> b) -> a -> b
$ OID -> [(OID, SignatureALG)] -> Maybe SignatureALG
forall a b. Eq a => a -> [(a, b)] -> Maybe b
lookup OID
oid [(OID, SignatureALG)]
sig_table

sigOID :: SignatureALG -> OID
sigOID :: SignatureALG -> OID
sigOID (SignatureALG_Unknown OID
oid) = OID
oid
sigOID SignatureALG
sig =
    OID
-> ((OID, SignatureALG) -> OID) -> Maybe (OID, SignatureALG) -> OID
forall b a. b -> (a -> b) -> Maybe a -> b
maybe (String -> OID
forall a. HasCallStack => String -> a
error (String
"unknown OID for " String -> ShowS
forall a. [a] -> [a] -> [a]
++ SignatureALG -> String
forall a. Show a => a -> String
show SignatureALG
sig)) (OID, SignatureALG) -> OID
forall a b. (a, b) -> a
fst (Maybe (OID, SignatureALG) -> OID)
-> Maybe (OID, SignatureALG) -> OID
forall a b. (a -> b) -> a -> b
$
        ((OID, SignatureALG) -> Bool)
-> [(OID, SignatureALG)] -> Maybe (OID, SignatureALG)
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Maybe a
find (SignatureALG -> SignatureALG -> Bool
forall a. Eq a => a -> a -> Bool
(==) SignatureALG
sig (SignatureALG -> Bool)
-> ((OID, SignatureALG) -> SignatureALG)
-> (OID, SignatureALG)
-> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (OID, SignatureALG) -> SignatureALG
forall a b. (a, b) -> b
snd) [(OID, SignatureALG)]
sig_table

-- | PSS salt length. Always assume ``-sigopt rsa_pss_saltlen:-1``
saltLen :: HashALG -> Integer
saltLen :: HashALG -> Integer
saltLen HashALG
HashSHA256 = Integer
32
saltLen HashALG
HashSHA384 = Integer
48
saltLen HashALG
HashSHA512 = Integer
64
saltLen HashALG
HashSHA224 = Integer
28
saltLen HashALG
_ = String -> Integer
forall a. HasCallStack => String -> a
error String
"toASN1: X509.SignatureAlg.HashAlg: Unknown hash"

instance ASN1Object SignatureALG where
    fromASN1 :: [ASN1] -> Either String (SignatureALG, [ASN1])
fromASN1 (Start ASN1ConstructionType
Sequence : OID OID
oid : ASN1
Null : End ASN1ConstructionType
Sequence : [ASN1]
xs) =
        case OID -> SignatureALG
oidSig OID
oid of
            SignatureALG_IntrinsicHash PubKeyALG
_ ->
                String -> Either String (SignatureALG, [ASN1])
forall a b. a -> Either a b
Left String
"fromASN1: X509.SignatureALG: EdDSA requires absent parameter"
            SignatureALG
signatureAlg -> (SignatureALG, [ASN1]) -> Either String (SignatureALG, [ASN1])
forall a b. b -> Either a b
Right (SignatureALG
signatureAlg, [ASN1]
xs)
    fromASN1 (Start ASN1ConstructionType
Sequence : OID OID
oid : End ASN1ConstructionType
Sequence : [ASN1]
xs) =
        (SignatureALG, [ASN1]) -> Either String (SignatureALG, [ASN1])
forall a b. b -> Either a b
Right (OID -> SignatureALG
oidSig OID
oid, [ASN1]
xs)
    fromASN1
        ( Start ASN1ConstructionType
Sequence : OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
10] : Start ASN1ConstructionType
Sequence : Start ASN1ConstructionType
_
                : Start ASN1ConstructionType
Sequence
                : OID OID
hash1
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
_
                : Start ASN1ConstructionType
_
                : Start ASN1ConstructionType
Sequence
                : OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
8]
                : Start ASN1ConstructionType
Sequence
                : OID OID
_hash2
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
_
                : Start ASN1ConstructionType
_
                : IntVal Integer
_iv
                : End ASN1ConstructionType
_
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
Sequence
                : [ASN1]
xs
            ) =
            (SignatureALG, [ASN1]) -> Either String (SignatureALG, [ASN1])
forall a b. b -> Either a b
Right (OID -> SignatureALG
oidSig OID
hash1, [ASN1]
xs)
    fromASN1
        ( Start ASN1ConstructionType
Sequence : OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
10] : Start ASN1ConstructionType
Sequence : Start ASN1ConstructionType
_
                : Start ASN1ConstructionType
Sequence
                : OID OID
hash1
                : ASN1
Null
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
_
                : Start ASN1ConstructionType
_
                : Start ASN1ConstructionType
Sequence
                : OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
8]
                : Start ASN1ConstructionType
Sequence
                : OID OID
_hash2
                : ASN1
Null
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
_
                : Start ASN1ConstructionType
_
                : IntVal Integer
_iv
                : End ASN1ConstructionType
_
                : End ASN1ConstructionType
Sequence
                : End ASN1ConstructionType
Sequence
                : [ASN1]
xs
            ) =
            (SignatureALG, [ASN1]) -> Either String (SignatureALG, [ASN1])
forall a b. b -> Either a b
Right (OID -> SignatureALG
oidSig OID
hash1, [ASN1]
xs)
    fromASN1 [ASN1]
_ =
        String -> Either String (SignatureALG, [ASN1])
forall a b. a -> Either a b
Left String
"fromASN1: X509.SignatureALG: unknown format"
    toASN1 :: SignatureALG -> ASN1S
toASN1 (SignatureALG_Unknown OID
oid) = \[ASN1]
xs -> ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID OID
oid ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1
Null ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: [ASN1]
xs
    toASN1 signatureAlg :: SignatureALG
signatureAlg@(SignatureALG HashALG
hashAlg PubKeyALG
PubKeyALG_RSAPSS) = \[ASN1]
xs ->
        ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
10]
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
0)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID (SignatureALG -> OID
sigOID SignatureALG
signatureAlg)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
0)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
1)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID [Integer
1, Integer
2, Integer
840, Integer
113549, Integer
1, Integer
1, Integer
8]
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID (SignatureALG -> OID
sigOID SignatureALG
signatureAlg)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
1)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
Start (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
2)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: Integer -> ASN1
IntVal (HashALG -> Integer
saltLen HashALG
hashAlg)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End (ASN1Class -> Int -> ASN1ConstructionType
Container ASN1Class
Context Int
2)
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence
            ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: [ASN1]
xs
    toASN1 signatureAlg :: SignatureALG
signatureAlg@(SignatureALG_IntrinsicHash PubKeyALG
_) = \[ASN1]
xs -> ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID (SignatureALG -> OID
sigOID SignatureALG
signatureAlg) ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: [ASN1]
xs
    toASN1 SignatureALG
signatureAlg = \[ASN1]
xs -> ASN1ConstructionType -> ASN1
Start ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: OID -> ASN1
OID (SignatureALG -> OID
sigOID SignatureALG
signatureAlg) ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1
Null ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: ASN1ConstructionType -> ASN1
End ASN1ConstructionType
Sequence ASN1 -> ASN1S
forall a. a -> [a] -> [a]
: [ASN1]
xs