Difference between KeyBuilder and KeyPair

[Vlidda]

I have doubts about key generation when writing my java card applet. I wonder the difference between KeyBuilder and KeyPair and also the difference between buildKey and KeyPair as well.
And what type of memory is used by the genKeyPair() method, Transient or Persistent ? Many thanks for any help.

[chico0609]

buildKey is not used to generate a key.

And what type of memory is used by the genKeyPair() method, Transient or Persistent ?

From my understanding, it is common for a smart cards to have RAM dedicated to cryptographic operations. In fact, as much of the operation as possible is done in transient RAM. For key objects, you can specify where the key material is stored. This is specified when you create the key object.

[Vlidda]

I used new state to generate RSA keypair object, does it mean that the key objects will be stored in persistent memory?

Code: Select all

KeyPair RSA_KEYP= new KeyPair(KeyPair.ALG_RSA_CRT, (short)1024);
RSA_KEYP.genKeyPair();
rsa_PublicKey = (RSAPublicKey)RSA_KEYP.getPublic();
rsa_PrivateKey=(RSAPrivateCrtKey)RSA_KEYP.getPrivate();               

[chico0609]

Yes, if you use new statement, the key objects will be stored in persistent memory.

You just need to write once and then you can read many times.