# Enum sequoia_openpgp::types::Curve [−][src]

```
pub enum Curve {
NistP256,
NistP384,
NistP521,
BrainpoolP256,
BrainpoolP512,
Ed25519,
Cv25519,
Unknown(Box<[u8]>),
}
```

## Expand description

Elliptic curves used in OpenPGP.

`PublicKeyAlgorithm`

does not differentiate between elliptic
curves. Instead, the curve is specified using an OID prepended to
the key material. We provide this type to be able to match on the
curves.

Note: This enum cannot be exhaustively matched to allow future extensions.

## Variants

NIST curve P-256.

NIST curve P-384.

NIST curve P-521.

brainpoolP256r1.

brainpoolP512r1.

D.J. Bernstein’s “Twisted” Edwards curve Ed25519.

Elliptic curve Diffie-Hellman using D.J. Bernstein’s Curve25519.

Unknown curve.

## Implementations

Returns the length of public keys over this curve in bits.

For the Kobliz curves this is the size of the underlying finite field. For X25519 it is 256.

Note: This information is useless and should not be used to gauge the security of a particular curve. This function exists only because some legacy PGP application like HKP need it.

Returns `None`

for unknown curves.

# Examples

```
use sequoia_openpgp as openpgp;
use openpgp::types::Curve;
assert_eq!(Curve::NistP256.bits(), Some(256));
assert_eq!(Curve::NistP384.bits(), Some(384));
assert_eq!(Curve::Ed25519.bits(), Some(256));
assert_eq!(Curve::Unknown(Box::new([0x2B, 0x11])).bits(), None);
```

Parses the given OID.

# Examples

```
use sequoia_openpgp as openpgp;
use openpgp::types::Curve;
assert_eq!(Curve::from_oid(&[0x2B, 0x81, 0x04, 0x00, 0x22]), Curve::NistP384);
assert_eq!(Curve::from_oid(&[0x2B, 0x11]), Curve::Unknown(Box::new([0x2B, 0x11])));
```

Returns this curve’s OID.

# Examples

```
use sequoia_openpgp as openpgp;
use openpgp::types::Curve;
assert_eq!(Curve::NistP384.oid(), &[0x2B, 0x81, 0x04, 0x00, 0x22]);
assert_eq!(Curve::Unknown(Box::new([0x2B, 0x11])).oid(), &[0x2B, 0x11]);
```

Returns the length of a coordinate in bits.

# Examples

```
use sequoia_openpgp as openpgp;
use openpgp::types::Curve;
assert!(if let Ok(256) = Curve::NistP256.len() { true } else { false });
assert!(if let Ok(384) = Curve::NistP384.len() { true } else { false });
assert!(if let Ok(256) = Curve::Ed25519.len() { true } else { false });
assert!(if let Err(_) = Curve::Unknown(Box::new([0x2B, 0x11])).len() { true } else { false });
```

# Errors

Returns `Error::UnsupportedEllipticCurve`

if the curve is not
supported.

Returns whether this algorithm is supported.

# Examples

```
use sequoia_openpgp as openpgp;
use openpgp::types::Curve;
assert!(Curve::Ed25519.is_supported());
assert!(!Curve::Unknown(Box::new([0x2B, 0x11])).is_supported());
```

## Trait Implementations

This method returns an ordering between `self`

and `other`

values if one exists. Read more

This method tests less than (for `self`

and `other`

) and is used by the `<`

operator. Read more

This method tests less than or equal to (for `self`

and `other`

) and is used by the `<=`

operator. Read more

This method tests greater than (for `self`

and `other`

) and is used by the `>`

operator. Read more

## Auto Trait Implementations

### impl RefUnwindSafe for Curve

### impl UnwindSafe for Curve

## Blanket Implementations

Mutably borrows from an owned value. Read more