Hi Lokesh, I am not sure how do you count the sizes of 164 bytes and 124 bytes for the pem files. If I use -outform DER (and use -noout with the ecparam to avoid outputting the params because the private key already contains info about the params used) I see the following sizes for the DER encoded data: private key: 121 bytes public key: 91 bytes Given both files contain information about the group used and other ASN.1 encoding related stuff, and that the private key file contains 32 bytes of the private key but also the encoded uncompressed public key of 65 bytes, this is fully expected. Tomas Mraz, OpenSSL On Wed, 2024-06-19 at 13:45 +0530, Lokesh Chakka wrote: > hello, > > I'm trying to generate public/private keys with following commands: > > openssl ecparam -name secp256r1 -genkey -out pvtkey.pem > openssl ec -in pvtkey.pem -pubout > > I'm seeing the sizeof private key as 164 bytes and public key as 124 > bytes. > > In a wireshark capture( attached ), I'm seeing key length as 65 > bytes. > > Can someone help me understand why the difference? > > Thanks & Regards > -- > Lokesh Chakka. -- Tomáš Mráz, OpenSSL
