When trying to retrieve the value of a pubkey using the Value Attribute the vector is coming empty

[shivam560]

pub fn create_key_pair() -> Result<Vec<u8>,()> {

    let (pkcs111,slit) = init_pins();
    let session = pkcs111.open_rw_session(slit).unwrap();
    session.login(cryptoki::session::UserType::User, Some("1234"));
  
    let class = ObjectClass::PUBLIC_KEY;
    let temp = vec![
        
        Attribute::Class(class),
        Attribute::Label("mykey".as_bytes().try_into().unwrap()),
      Attribute::KeyType(KeyType::RSA),
      
       
    ];
    
    let publickeyhandle =  session.find_objects(&temp).unwrap().pop().expect("No public key found in slot");
    println!("The pubkeyhandle is {}",publickeyhandle);
    let new_pub_key = session.get_attributes(publickeyhandle, &[AttributeType::CheckValue]).unwrap();
    println!("The length is {}",new_pub_key.len());
    let value = if let Attribute::Value(value) = new_pub_key[0].clone() {
        value
    } else {
        panic!("Expected value attribute.");
    };  
 
         Ok(value)
}

In the above code pubkeyhandle is coming as 2
but the new_pub_key is an empty vector.

in terminal when i am checking for objects I see slot 0 is initialized with pubkey

pkcs11-tool --module /usr/lib/softhsm/libsofthsm2.so --slot-index 0 --list-objects --type pubkey

Using slot with index 0 (0x1c85df1e)
Public Key Object; RSA 2048 bits
  label:      mykey
  Usage:      encrypt, verify, wrap
  Access:     local

But still new_pub_key is still coming as an empty vector

[shivam560]

@baloo @vkkoskie @wiktor-k @gowthamsk-arm
I could use some help here. I am getting an empty vector when calling get_attributes() using Attribute::Value. i generated the keys using the pkcs11-tool command in ubuntu

[baloo]

You are requesting the CHECK_VALUE attribute in the new_pub_key variable:
https://docs.oasis-open.org/pkcs11/pkcs11-spec/v3.1/cs01/pkcs11-spec-v3.1-cs01.html#_Toc111203232

CKA_CHECK_VALUE | Byte   array | Key   checksum

I'm not sure this what you intend to use.
I think you're looking for CKA_MODULUS and CKA_PUBLIC_EXPONENT for an RSA key

[ionut-arm]

Indeed, this sounds right to me.

@shivam560 - you can see an example of how we get existing keys in Parsec here. We just populate the ID attribute (which we know from when we generated the key), but if you don't know that (and for some reason pkcs11-tool doesn't tell you the ID........) you can just populate Attribute::Label in the same way (just need to convert mykey to a vector of bytes).