During boot, the elliptic curve digital signature algorithm (ECDSA) is only supported with the NIST P-384 curve for the PLM, while other images can be signed using either the NIST P-384 curve or the NIST P-521 curve. However, post boot, the elliptic curve cryptography (ECC) engine is accessible, and supports a variety of curves in addition to the NIST P-384 curve. Supported curves are NIST P-384 and NIST P-521.