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TMayd's avatar
TMayd
Icon for Occasional Contributor rankOccasional Contributor
7 years ago
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Can you use the non-volatile key from the FPGA (Cyclone V) in a design?

So we would like to use the fused non-volatile key in the Cyclone V to provide our application with a seed for an SHA-256 algorithm. It's not clear to me if you can set this fuse and then access the value internally in the FPGA design? Primarily it would be nice to have a permanent secret key so that when we update the devices it doesn't need a specific bitstream file for each FPGA. Or am I misunderstanding the encrypted FPGA programming?

  • Nooraini_Y_Intel's avatar
    Nooraini_Y_Intel
    7 years ago
    Hi TMayd, Yes, the programmed non-volatile key is use to decrypt the configuration bitstream during the configuration process. The general process flow is shown in figure 1 from AN556. Once you program the non-volatile key, is it OTP, there is no way to repogram with a different value. You can generate multiple key files and encrypted image files . However once you program the non-volatile key into Cyclone V, the decryption engine can only decrypt the matching encrypted image. Regards, Nooraini

3 Replies

    • TMayd's avatar
      TMayd
      Icon for Occasional Contributor rankOccasional Contributor
      7 years ago

      Hi, so since the value is not a register it's only primary use is de-encrypting the bit file? I can't use this value in a design to have a fixed value that won't change with a new bit file?

  • Nooraini_Y_Intel's avatar
    Nooraini_Y_Intel
    Icon for Frequent Contributor rankFrequent Contributor
    7 years ago
    Hi TMayd, Yes, the programmed non-volatile key is use to decrypt the configuration bitstream during the configuration process. The general process flow is shown in figure 1 from AN556. Once you program the non-volatile key, is it OTP, there is no way to repogram with a different value. You can generate multiple key files and encrypted image files . However once you program the non-volatile key into Cyclone V, the decryption engine can only decrypt the matching encrypted image. Regards, Nooraini