SRKTOOL(1)

NAME
srktool - Generate SRK Table and eFuse hash for secure boot on NXP i.MX processors (HAB4 and AHAB)

SYNOPSIS
srktool --ahab_ver --table file --efuses file --digest algo --sign_digest algo --certs certs,... [--fuse_format format] [--license] [--version] [--verbose]

srktool --hab_ver 4 --table file --efuses file --digest sha256 --certs certs,... [--fuse_format format] [--license] [--version] [--verbose]

DESCRIPTION
srktool is a utility for generating Super Root Key (SRK) tables and eFuse hash binaries required for enabling secure boot on NXP i.MX SoCs using either HAB4 or AHAB mechanisms.

It processes up to four X.509 certificates (PEM or DER format), and produces a binary SRK table and a corresponding hash file suitable for programming into fuses.

OPTIONS

-a, --ahab_ver
    Target platform uses AHAB (Advanced High Assurance Boot), e.g., i.MX 8/8X/8ULP series.

-h, --hab_ver version
    Target platform uses HAB (High Assurance Boot), e.g. i.MX 6. The version must be set to 4.

-t, --table file
    Output file path for the generated SRK table.

-e, --efuses file
    Output file path for the generated eFuse binary containing the SRK table hash.

-d, --digest digestalg
    Digest algorithm used to compute the SRK table hash. This is required for both AHAB and HAB4.

    For AHAB, one of:

    •   "sha512": supported in i.MX 8/8X and is the default.

    •   "sha256": supported in i.MX 8ULP.

    For HAB4, only "sha256" is supported.

-s, --sign_digest digestalg
    Signature digest algorithm used to sign the SRK certificates. One of: "sha256", "sha384", "sha512"

    This option is only valid for AHAB.

-c, --certs cert1[,cert2,...,cert4]
    Comma-separated list of up to 4 X.509 certificate files (PEM or DER).

    •   PEM or DER format supported

    •   No whitespace allowed between filenames

    •   For HAB4: Prefix a cert with "%" to include only its public key hash instead of the full key

-f, --fuse_format format
    Optional fuse data output format:

    •   0: 8 fuses per word (e.g., "00 00 00 0a 00 00 00 01 ...")

    •   1: 32 fuses per word (default; e.g., "0a 01 ff 8e")

-l, --license
    Print license information and exit.

-v, --version
    Print the tool version and exit.

-b, --verbose
    Enable verbose output.

EXAMPLES

  AHAB Example
Generate an AHAB-compatible SRK table and eFuse file with SHA-512 digest and certificate signatures using SHA-384:

  srktool --ahab_ver \
          --digest sha512 --sign_digest sha384 \
          --table srk_table.bin --efuses srk_fuse.bin \
          --certs srk1.pem,srk2.pem,srk3.pem

  HAB4 Example
Generate a HAB4-compatible SRK table using SHA-256 and a mix of full and digest-style certificates:

  srktool --hab_ver 4 --digest sha256 \
          --table srk_table.bin --efuses srk_fuse.bin \
          --certs srk1.pem,srk2.pem,%srk3.pem

FILE FORMATS

•   Certificates may be DER or PEM format.

•   Output files (SRK table and efuse) are binary.

SEE ALSO
cst(1), csf_parser(1)