IMPLEMENT_ASN1_FUNCTIONS tutorial or help

[Ken Goldman]

On 8/17/2021 10:38 AM, Matt Caswell wrote:
> 
> 
> On 16/08/2021 21:56, Ken Goldman wrote:
>> I am trying to parse some ASN.1 DER so I can add it to an X.509 certificate.
>>
>> For the input side, a poster showed me
>>
>> ASN1_SEQUENCE, ASN1_SEQUENCE_END, and then
>> DECLARE_ASN1_FUNCTIONS, IMPLEMENT_ASN1_FUNCTIONS
>>
>> which created the i2d() function.
> 
> It should also give you the d2i() function too!
> 
> 
>>
>> Now I would like to do the other end, where I have der and I
>> want to parse back to the structure, using d2i()
>>
>> 1 - Is there a tutorial on this?
> 
> Seems like you don't need one. If you got i2d working you should have d2i already!
> 

I wasn't clear.  The input and output sides are different asn.1.

For the input side, a poster give me the structure and I only need the
i2d().  That's done - amazing.

This worked so well that I would like to use the same pattern for
the output side, where I need d2i().

I posted the DER dump below, but I don't know how to map that
to the structures that the openssl macros can consume.


> Matt
> 
> 
>>
>> 2 - Can someone show me this structure?
>>
>> The DER is a version, serial number, signature algorithm,
>> public key algorithm, and public key.
>>
>> The dump looks like this:
>>
>>   0 337: SEQUENCE {
>>    4   3: . [0] {
>>    6   1: . . INTEGER 2
>>         : . . }
>>    9  21: . INTEGER 00 87 12 50 78 0A C9 8B 60 DD AC FA 75 18 05 EC DC 30 51 53 23
>>   32  13: . SEQUENCE {
>>   34   9: . . OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11)
>>         : . . . (PKCS #1)
>>   45   0: . . NULL
>>         : . . }
>>   47 290: . SEQUENCE {
>>   51  13: . . SEQUENCE {
>>   53   9: . . . OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1)
>>         : . . . . (PKCS #1)
>>   64   0: . . . NULL
>>         : . . . }
>>   66 271: . . BIT STRING, encapsulates {
>>   71 266: . . . SEQUENCE {
>>   75 257: . . . . INTEGER
>>         : . . . . . 00 B0 83 4A E9 41 78 E0 6A C3 0F D6 E4 B9 7D 96
>>         : . . . . . 70 74 05 00 C9 E2 2C 6C 4C 6E 16 02 40 5C 35 29
>>         : . . . . . F6 EF 9F 55 3A BD 4B 74 1D 6A 21 38 20 69 C8 88
>>         : . . . . . A3 6B 56 62 2A 91 02 41 58 92 97 87 19 1C AD 19
>>         : . . . . . 53 56 FB 7E 9D 86 B8 4E 8D 82 6A 87 A7 93 55 8F
>>         : . . . . . AB E8 89 D7 63 0B C9 02 99 D8 37 F8 FB 6B 32 98
>>         : . . . . . 6A 05 3F 9E 22 B6 D3 6F BB BE 2D AC 6C 74 17 5D
>>         : . . . . . 15 EE 84 E5 A4 8F 9C C3 83 CD 83 81 63 EC B5 85
>>         : . . . . . 6B 1A B8 57 80 2C ED E3 A7 F2 8C F7 3F 13 D9 27
>>         : . . . . . 2E 64 37 49 E6 47 8E 0A 11 64 46 72 DD F9 EB 4F
>>         : . . . . . B8 13 58 0B 47 F7 72 AB 29 D6 A5 05 44 30 E7 8D
>>         : . . . . . FE 86 8A E8 5F 10 91 13 04 57 47 96 A7 97 28 3C
>>         : . . . . . 39 BD 23 3F C6 41 5E 45 3F A5 41 F5 BF 7D C2 7C
>>         : . . . . . CC F9 97 20 3F 20 82 AF 64 8C BC 0D 99 F4 BA 10
>>         : . . . . . 53 58 C5 EC 86 DE 26 ED D9 D6 F2 60 49 C9 E7 9B
>>         : . . . . . 6A 64 D2 BC C5 0E B0 1D EB 45 43 89 A6 4E 64 B4
>>         : . . . . . A1
>> 336   3: . . . . INTEGER 65537
>>         : . . . . }
>>         : . . . }
>>         : . . }
>>         : . }
>>
>>
>