ZMS-125

[NickOvt]

• Added ed25519 assymetric crypographic keys support for DKIM

[andris9]

WildDuck should be able to accept the following example values as private key for ed25519 (both are the same keys):

1. PEM encoded value

-----BEGIN PRIVATE KEY-----
MC4CAQAwBQYDK2VwBCIEIJ1hsZ3v/VpguoRK9JLsLMREScVpezJpGXA7rAMcrn9g
-----END PRIVATE KEY-----

2. raw keys (base64 encoded)

nWGxne/9WmC6hEr0kuwsxERJxWl7MmkZcDusAxyuf2A=

Raw ed25519 keys are always 32 byte binary, so 44 bytes as base64 (or 43 bytes as base64url or if the ending "=" padding is removed). You can find an example for converting raw ed25519 key to pem here (not the best solution, but the easiest)

There is no need to store DER encoded public key as it is just an alternative form for PEM (DER is the same value as PEM but without the ---BEGIN/END--- padding, and it is binary, not base64)

You can convert the public key file object to ed25519 public key (this is not pem and not der!) with this approach (basically just cut away the ASN padding):

const ed25518PubKey = publicKey.export({ format: 'der', type: 'spki' }).subarray(12).toString('base64');