ECDSA Cryptography

Elliptic curve cryptography for key generation, signing, verification, and key import/export.

Provides ECDSA cryptographic operations including key pair generation, digital signing, signature verification, and key recovery from signatures. Supports NIST P-192 through P-521, SECP256k1, Ed25519, and Ed448 curves with SHA-1/2/3 hash functions. Handles PEM, DER, base64, and SSH key formats.