pkcs1/version.rs
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//! PKCS#1 version identifier.
use crate::Error;
use der::{Decode, Encode, FixedTag, Reader, Tag, Writer};
/// Version identifier for PKCS#1 documents as defined in
/// [RFC 8017 Appendix 1.2].
///
/// > version is the version number, for compatibility with future
/// > revisions of this document. It SHALL be 0 for this version of the
/// > document, unless multi-prime is used; in which case, it SHALL be 1.
///
/// ```text
/// Version ::= INTEGER { two-prime(0), multi(1) }
/// (CONSTRAINED BY
/// {-- version must be multi if otherPrimeInfos present --})
/// ```
///
/// [RFC 8017 Appendix 1.2]: https://datatracker.ietf.org/doc/html/rfc8017#appendix-A.1.2
#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
#[repr(u8)]
pub enum Version {
/// Denotes a `two-prime` key
TwoPrime = 0,
/// Denotes a `multi` (i.e. multi-prime) key
Multi = 1,
}
impl Version {
/// Is this a multi-prime RSA key?
pub fn is_multi(self) -> bool {
self == Self::Multi
}
}
impl From<Version> for u8 {
fn from(version: Version) -> Self {
version as u8
}
}
impl TryFrom<u8> for Version {
type Error = Error;
fn try_from(byte: u8) -> Result<Version, Error> {
match byte {
0 => Ok(Version::TwoPrime),
1 => Ok(Version::Multi),
_ => Err(Error::Version),
}
}
}
impl<'a> Decode<'a> for Version {
fn decode<R: Reader<'a>>(decoder: &mut R) -> der::Result<Self> {
Version::try_from(u8::decode(decoder)?).map_err(|_| Self::TAG.value_error())
}
}
impl Encode for Version {
fn encoded_len(&self) -> der::Result<der::Length> {
der::Length::ONE.for_tlv()
}
fn encode(&self, writer: &mut impl Writer) -> der::Result<()> {
u8::from(*self).encode(writer)
}
}
impl FixedTag for Version {
const TAG: Tag = Tag::Integer;
}