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What's SDA and DDA?
Posted: Tue Dec 01, 2015 3:02 am
by lostsiwonlw
"JavaCard supports 2048 bits key length only in DDA.", said in a java card doc provided by card manufacturer.
So my question is what is DDA and SDA? How can I install applet in this mode.
ps. I only know that
SDA: Static Data Authentication
DDA: Dynamic Data Authentication
Re: What's SDA and DDA?
Posted: Wed Dec 02, 2015 8:48 am
by horse dream
FYI,
SDA ensures the authenticity of ICC data. After SDA it is sure that the data from the ICC is real and hasn't changed by anyone. But SDA doesn't assure the uniqueness of ICC data. SDA guarantees that data on cards is valid because we trust a high level certification authority which signs the data. But an attacker can record a card session and build for example a new virtuel card because same data is used here for all session.
But in DDA flow - we can say it is checking SDA + giving random data to card by Terminal to sign and here this part makes cloning of card impossible because each session use different random number so recording a card session will not work in next card session.