How to view the ASN.1 structure of an DH public key using the OpenSSL "asn1parse" command?

You can use the OpenSSL "asn1parse" command to view the ASN.1 structure of an DH public key as shown in the test below:

C:\Users\fyicenter>\local\openssl\openssl 
   pkey -in dh_pri.key -pubout -out dh_pub.key

C:\Users\fyicenter>\local\openssl\openssl asn1parse -in dh_pub.key -i
    0:d=0  hl=2 l=  90 cons: SEQUENCE
    2:d=1  hl=2 l=  51 cons:  SEQUENCE
    4:d=2  hl=2 l=   9 prim:   OBJECT            :dhKeyAgreement
   15:d=2  hl=2 l=  38 cons:   SEQUENCE
   17:d=3  hl=2 l=  33 prim:    INTEGER           :8B58E1395DF5CF48DA87B088C6525
EFF4AECBDA5C269EF2378A31A4A62B1647B
   52:d=3  hl=2 l=   1 prim:    INTEGER           :02
   55:d=1  hl=2 l=  35 prim:  BIT STRING
   
C:\Users\fyicenter>\local\openssl\openssl 
   asn1parse -in dh_pub.key -strparse 55
    0:d=0  hl=2 l=  32 prim: INTEGER           :4CC9C94CEB5B13F2B4B3ABB9F20CB830
FFC3BB5DC6428C08B18CF3E5301908AD

C:\Users\fyicenter>\local\openssl\openssl pkey -pubin -in dh_pub.key -text -noout
DH Public-Key: (256 bit)
    public-key:
        4c:c9:c9:4c:eb:5b:13:f2:b4:b3:ab:b9:f2:0c:b8:
        30:ff:c3:bb:5d:c6:42:8c:08:b1:8c:f3:e5:30:19:
        08:ad
    prime:
        00:8b:58:e1:39:5d:f5:cf:48:da:87:b0:88:c6:52:
        5e:ff:4a:ec:bd:a5:c2:69:ef:23:78:a3:1a:4a:62:
        b1:64:7b
    generator: 2 (0x2)

Note about the test:

• The ASN.1 structure of a DH public key is identical to the DH private key, except that the public integer is wrapped in an BIT STRING instead of an OCTET STRING.
• The ASN.1 structure of a DH public key has no version field.

⇒ OpenSSL "ans1parse" - Configuration File for DH Public Key

⇐ OpenSSL "ans1parse" - Configuration File for DH Private Key

⇑ OpenSSL "ans1parse" Command

⇑⇑ OpenSSL Tutorials