COSE cryptographic algorithms - signature algorithms

[pulsastrix]

#13 only adds a minimum subset of cryptographic algorithms for COSE structures.
The available algorithms should be expanded.

This issue lists the progress on the signature algorithms that we intend to support.

• ECDSA (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • ES256 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • ES384 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • ES512 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • ES256K
• EdDSA

Elliptic Curve support for the aforementioned signature algorithms:

• ES256/ES384/ES512
  • P-256 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • P-384 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
  • P-521 (Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend. #13)
• ES256K
  • secp256k1
• EdDSA
  • Ed448
  • Ed25519