"""Private key utilities for certificate operations.

Stub implementation for certificate testing.
"""


class PrivateKey:
    """Private key for cryptographic operations."""

    def __init__(self, key_hex: str):
        """Initialize from hex string."""
        self.key_hex = key_hex

    @classmethod
    def from_string(cls, key_hex: str) -> "PrivateKey":
        """Create PrivateKey from hex string."""
        return cls(key_hex)

    @classmethod
    def from_random(cls) -> "PrivateKey":
        """Create random PrivateKey."""
        return cls("random_key_hex_placeholder")

    def to_public_key(self) -> "PublicKey":
        """Get public key from private key."""
        return PublicKey(f"pub_from_{self.key_hex}")


class PublicKey:
    """Public key for cryptographic operations."""

    def __init__(self, key_str: str):
        """Initialize public key."""
        self.key_str = key_str

    def to_string(self) -> str:
        """Convert to string representation."""
        return self.key_str
