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chain of trust

Each boot stage verifies the next stage's signature before running it, starting from the root of trust.

A chain of trust is a boot sequence in which each stage cryptographically verifies the next before transferring control to it, so trust extends from the root of trust to the running application.

Examples

  • The ESP32 ROM checks the second-stage bootloader's signature, and the bootloader checks the app's signature before starting it.

  • Each link only runs the next stage after verifying it, so a tampered app image is refused at boot.

See also

root of trust secure boot digital signature
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