2026-04-16 15:41:34
In my recent post on the PSA Crypto API, I demonstrated the use of the API on two different MCUs: the nRF52840 and the ESP32-S3. In the case of the former, the ECDSA signature operation was eventually executed in a closed source library that manages communication between the Arm Cortex-M4 processor and the Arm TrustZone CryptoCell 310 security subsytem. Readers that ventured down the rabbit hole of links in the post may have noticed that there are variants of the nrf_cc310_mbedcrypto libraries for hard-float and soft-float.
2026-04-10 15:41:34
Arm’s Platform Security Architecture (PSA) was released in 2017, but it was two years until the first beta release of the PSA Cryptography API in 2019, and another year until the 1.0 specification in 2020. Aimed at securing connected devices and originally targeting only Arm-based systems, PSA has evolved with the donation of the PSA Certified program to GlobalPlatform in 2025, allowing non-Arm devices, such as popular RISC-V microcontrollers (MCUs), to achieve certification.
2026-03-01 15:41:34
Below are two X.509 certificates. The first is the Certificate Authority (CA) root certificate, and the second is a leaf certifcate signed by the private key of the CA. ca.crt.pem -----BEGIN CERTIFICATE----- MIIBejCCASGgAwIBAgIUda4UvlFzwQEO/fD0f4hAnj+ydPYwCgYIKoZIzj0EAwIw EjEQMA4GA1UEAxMHUm9vdCBDQTAgFw0yNjAyMjcxOTQ3NDZaGA8yMTI2MDIwMzE5 NDc0NlowEjEQMA4GA1UEAxMHUm9vdCBDQTBZMBMGByqGSM49AgEGCCqGSM49AwEH A0IABKL5BB9aaQ2TtNgUymEsa/+s2ZlTXVll0N22KKWxh0N/JdgHcjrKfzqRlVrt UN2GXdvsdLOq15TxBq97WvE07lKjUzBRMB0GA1UdDgQWBBTAVEw9doSzY1DuPVxP EnwEp/+VJDAfBgNVHSMEGDAWgBTAVEw9doSzY1DuPVxPEnwEp/+VJDAPBgNVHRMB Af8EBTADAQH/MAoGCCqGSM49BAMCA0cAMEQCIHrSTk/KJHAjn3MC/egvfxMM1NpG GEzMB7EH+VXWz7RfAiAyhwy4E9hc8/qsTI+4iKf2o/zMRu5H2GNJOLqOngglbQ== -----END CERTIFICATE----- leaf.crt.pem -----BEGIN CERTIFICATE----- MIIBHjCBxAIULE3hvnYxU91g9c9H3+uGCSqXi4MwCgYIKoZIzj0EAwIwEjEQMA4G A1UEAwwHUm9vdCBDQTAgFw0yNjAyMjcxOTQ3NDZaGA8yMTI2MDIwMzE5NDc0Nlow DzENMAsGA1UEAwwEbGVhZjBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABKDZ21Yh +1AQp1TrxrS8FquIVEHrFRSXncX9xl5vVhZFqvblzTp2Tg7TER5x7rHG1TIqQL1z xDX4TB+nZOWkyAcwCgYIKoZIzj0EAwIDSQAwRgIhAMeo5t2d1RWL/SB0E+mvvIZP jFT0wDWX1Bm26MtxRcf9AiEApG96fs70WF1JliFgzkTiNvbG7Gj4SvErZ9nNX/Lr PnA= -----END CERTIFICATE----- If you downloaded these certificates, you could visually see that the latter references the former as its Issuer.
2026-02-01 15:41:34
I have recently been working on tuning circuits, which typically consist of an inductor and a capacitor (i.e. an LC circuit). For those not familiar with inductors, they are passive components that store energy in a magnetic field. They oppose changes in current, meaning that they pass direct current (DC) and block alternating current (AC). While there are many types of inductors, ferrite core inductors are useful because the high magnetic permeability of ferrite leads to a significant increase in induction.
2026-01-19 15:41:34
A few months ago I wrote Make it Possible, Then Make it Normal, in which I described unceremoniously running my 3,000th mile of 2025 nearly two months before the year concluded. While I didn’t have a total mileage goal for the year, after hitting 3,000 with time to spare I naturally locked on to trying to reach 3,500. I crossed the threshold on December 30th, 2025 and finished with a final tally of 3,507.
2025-12-30 15:41:34
Minutes before a recent video call where I was slated to give a demo, I initiated a reboot on my System76 Oryx Pro laptop, but it did not come back up after seemingly powering off. I attempted to manually power on and found it unresponsive. The machine was connected to power, so I saw the familiar power and battery LEDs illuminated on the front of the machine. Given that the machine appeared to not even be attempting to boot, I suspected that the issue was likely related to power or the battery.
