Host Protocols Direct Protocol ATCRYPTO class ECDH
April 13, 2023 at 2:39 AMSIGN instruction
Role
This instruction allows to run a Diffie-Hellman key agreement using one of the ECC private keys stored in the ATECC Secure Element.
Access condition
Depending on the configuration-defined access conditions and on the type of host interface (Local / Remote), this instruction may either be freely usable or restricted to authenticated communications.
Command
| Field | Value |
|---|---|
| CLA | 59 (ATCRYPTO) |
| INS | 48 |
| Data byte 0 | Key index (00 to 0D) |
| Data byte 1..64 | Peer’s Public Key X and Y coordinates (2 x 32 = 64 bytes) |
Response
| Field | Value |
|---|---|
| CLA | 59 (ATCRYPTO) |
| STA | 00 |
| Data 0..31 | Shared Secret (32 bytes) |