Understood. Thanks alot. But I'm still Not able to understand why it is 65 bytes in the key value.
Thanks & Regards -- Lokesh Chakka. On Wed, Jun 19, 2024 at 3:03 PM Tomas Mraz <to...@openssl.org> wrote: > You need to do base64 decoding to find out the real size of the ASN.1 > encoded data. > > Tomas Mraz, OpenSSL > > On Wed, 2024-06-19 at 14:58 +0530, Lokesh Chakka wrote: > > hi, > > > > please check the following : > > > > ===================================================================== > > ===================== > > $ openssl ecparam -name secp256r1 -genkey -out pvtkey.pem > > using curve name prime256v1 instead of secp256r1 > > $ cat pvtkey.pem > > -----BEGIN EC PARAMETERS----- > > BggqhkjOPQMBBw== > > -----END EC PARAMETERS----- > > -----BEGIN EC PRIVATE KEY----- > > MHcCAQEEIAXXAWUj/cUQT8pDLKp5r269mw58aTzr/hYAEXQZVQqUoAoGCCqGSM49 > > AwEHoUQDQgAEVSmp4UnlQbzbe6eopByeEUzkmYHPGgaKvSt/xdAgvDp7FXKTpST8 > > UM9LpF8f4JETOXgDDGvNlIDqVFo+T0hdtQ== > > -----END EC PRIVATE KEY----- > > $ openssl ec -in pvtkey.pem -pubout > > read EC key > > writing EC key > > -----BEGIN PUBLIC KEY----- > > MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEVSmp4UnlQbzbe6eopByeEUzkmYHP > > GgaKvSt/xdAgvDp7FXKTpST8UM9LpF8f4JETOXgDDGvNlIDqVFo+T0hdtQ== > > -----END PUBLIC KEY----- > > ===================================================================== > > ===================== > > > > sizeof private key is 164 bytes and the public key is 124 bytes. > > > > > > Thanks & Regards > > -- > > Lokesh Chakka. > > > > > > On Wed, Jun 19, 2024 at 2:28 PM Tomas Mraz <to...@openssl.org> wrote: > > > 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 > >
