Re: [pkix] In-the-wild implementations of RFC6955?

[Michael StJohns <[e-mail]>]

This looks like a perfectly sane X25519 certificate, signed by what's 
probably a P521 CA.  You could remove the basicConstraints extension, 
but it shouldn't cause any problems being there.

I'm actually more interested in the CSR you used to get the CA to issue 
the certificate.

Thanks - Mike


On 5/26/2022 1:42 PM, Anders Rundgren wrote:
> It seems that things get a bit more challenging with ECDH using X25519 
> keys:
> https://mta.openssl.org/pipermail/openssl-users/2021-March/013549.html
>
> This is (hopefully) a proper ECDH certificate using an X25519 public key:
>
>
>    0: SEQUENCE {
>    4:   SEQUENCE {
>    8:     [0] {
>   10:       INTEGER 2
>           }
>   13:     INTEGER  01 80 fb 4a 58 1a
>   21:     SEQUENCE {
>   23:       OBJECT IDENTIFIER ecdsa-with-Sha512 (1.2.840.10045.4.3.4)
>           }
>   33:     SEQUENCE {
>   35:       SET {
>   37:         SEQUENCE {
>   39:           OBJECT IDENTIFIER commonName (2.5.4.3)
>   44:           PrintableString 'Test Sub CA'
>               }
>             }
>           }
>   57:     SEQUENCE {
>   59:       UTCTime 180101000000
>   74:       UTCTime 301231235959
>           }
>   89:     SEQUENCE {
>   91:       SET {
>   93:         SEQUENCE {
>   95:           OBJECT IDENTIFIER commonName (2.5.4.3)
>  100:           PrintableString 'Test certificate matching 
> x25519privatekey.pem'
>               }
>             }
>           }
>  148:     SEQUENCE {
>  150:       SEQUENCE {
>  152:         OBJECT IDENTIFIER X25519 (1.3.101.110)
>             }
>  157:       BIT STRING, 32 bytes
>       0000: e9 9a 0c ef 20 58 94 96 0d 9b 1c 05 97 85 13 dc '.... 
> X..........'
>       0010: cb 42 a1 3b fb ce d5 23 a5 1b 8a 11 7a d5 f0 0c 
> '.B.;...#....z...'
>           }
>  192:     [3] {
>  194:       SEQUENCE {
>  196:         SEQUENCE {
>  198:           OBJECT IDENTIFIER basicConstraints (2.5.29.19)
>  203:           OCTET STRING, encapsulates {
>  205:             SEQUENCE {
>                   }
>                 }
>               }
>  207:         SEQUENCE {
>  209:           OBJECT IDENTIFIER keyUsage (2.5.29.15)
>  214:           BOOLEAN true
>  217:           OCTET STRING, encapsulates {
>  219:             BIT STRING, 5 bits (unused=3) '00001'B
>                 }
>               }
>  223:         SEQUENCE {
>  225:           OBJECT IDENTIFIER subjectKeyIdentifier (2.5.29.14)
>  230:           OCTET STRING, encapsulates {
>  232:             OCTET STRING, 20 bytes
>       0000: b2 79 b5 8e 62 05 b5 3d e3 7c 6a 54 5e 36 de ae 
> '.y..b..=.|jT^6..'
>       0010: 02 90 08 98 '....'
>                 }
>               }
>  254:         SEQUENCE {
>  256:           OBJECT IDENTIFIER authorityKeyIdentifier (2.5.29.35)
>  261:           OCTET STRING, encapsulates {
>  263:             SEQUENCE {
>  265:               [0], 20 bytes
>       0000: a3 11 65 cf 5d c0 50 a7 4b e5 19 e1 76 7b 54 9a 
> '..e.].P.K...v{T.'
>       0010: b7 4f 97 8a '.O..'
>                   }
>                 }
>               }
>             }
>           }
>         }
>  287:   SEQUENCE {
>  289:     OBJECT IDENTIFIER ecdsa-with-Sha512 (1.2.840.10045.4.3.4)
>         }
>  299:   BIT STRING, encapsulates {
>  303:     SEQUENCE {
>  306:       INTEGER
>               01 b7 80 e4 b5 5c 68 90 81 39 15 03 f4 c1 da 08
>               df 9f 33 db 7b a4 e9 e3 f1 3b 5a ad 99 c3 07 9c
>               34 b4 09 a8 4a 7c 67 73 dc c2 51 e5 9e 6c 58 de
>               3e 54 45 47 e0 5d 42 b9 16 26 d5 86 c5 f4 86 3e
>               61 f2
>  374:       INTEGER
>               01 ba d7 5c a2 fa b8 39 6f 14 09 7c ff 55 45 88
>               9e 9d 9d 4d f3 44 cd de c8 de 92 75 f1 13 fb 54
>               43 92 5e 90 79 97 66 b9 bf ac 8e 88 b5 19 82 ad
>               d2 f1 04 e6 4c 94 d1 06 9d 64 8d 50 02 4a fe 48
>               72 7b
>           }
>         }
>       }
>
> Anders