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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 770
UG585 (v1.11) September 27, 2016
Chapter 32: Device Secure Boot
RSA Authentication Certificate Format
The RSA authentication certificate consists of three major components; the authentication header,
the PPK and SPK, and the SPK and FSBL signatures (see Figure 32-4). The authentication header is
32-bits with the following value 0x00000101, padded to a 512-bit boundary. Each public key
consists of three parts, a 2,048-bit modulus, a 2,048-bit modulus extension to speed up calculations,
and a 32-bit public exponent which gets padded to 512 bits. The other component is the 2,048-bit
SPK and FSBL signatures. Since SHA-256 is used as the secure hash algorithm, the FSBL, partition,
and authentication certificates must be padded to a 512-bit boundary.
X-Ref Target - Figure 32-3
Figure 32-3: Secure Boot Image Format
AES Encrypted Image
HMAC Authenticated Image
FSBL
HMAC Signature
Boot Image Header
UG585_c33_03_022513
Encrypted FSBL
(AES & HMAC)
FSBL RSA authentication
certificate (optional)
Partition
Partition
Partition RSA authentication
certificate (optional)
Partition RSA authentication
certificate (optional)
Partition
Partition RSA authentication
certificate (optional)
.
.
.
AES Encrypted Image
HMAC Authenticated Image
PS Image or PL Bitstream
HMAC Signature
Expansion Space