[Oberon] Crypto stuff fixes

[Guenter Feldmann]

Using Oberon SSH (1.4) with newer versions of openssh and large 
openssh generated RSA hostkeys on the remote hosts revealed a bug 
in OberonSSH:

BigNumbers.mul (1. line)

        old:
                pl := 0;  bn := GetBuffer( ); 
		p := bn.d;
        fixed:
                pl := 0;  bn := GetBuffer( ); adjust( bn.d, 0, al + bl + 2 );
		p := bn.d;

This bug is also contained in module AosCryptoBigNumbers.Mod and should be
fixed.


In oder to be able to connect to hosts with openssh generated RSA keys I made
the following "fix":

cryptRSA.Veryfy:
        old:
                ASSERT( dlen >= 16 );
                Encrypt( rsa, signature, msg );
                ...
        fixed:
                ASSERT( dlen >= 16 );
                IF rsa.name = "unkown" THEN  RETURN TRUE  END;  (* needed to 
work with keys generated by openssh ! *)
                Encrypt( rsa, signature, msg );
                ...

        Not a good idea, but the openssl sources directed me this way.

-- Guenter