Redesign of ed25519 key loading functions

[karel-m]

Currently we have:

int ed25519_set_key(sk, sklen, pk, pklen, &key);
int ed25519_import(in, inlen, &key);
int ed25519_import_x509(in, inlen, &key);
int ed25519_import_pkcs8(in, inlen, pwd, pwdlen, &dkey);

First, I propose replacing ed25519_set_key with:

int ed25519_import_raw(in, inlen, type, &key);
/* where type is PK_PRIVATE or PK_PUBLIC */

Next, I would suggest renaming ed25519_import to ed25519_import_openssl and extending it so that it can import not only public keys but also private keys produced by openssl (which is similar to what we do in ecc_import_openssl).

The test vectors can be generated by:

openssl genpkey -algorithm Ed25519 -out ed25519_sk.pem
openssl pkey -in ed25519_sk.pem -inform PEM -out ed25519_sk.der -outform DER
openssl pkey -in ed25519_sk.pem -inform PEM -out ed25519_pk.der -pubout -outform DER

Our ed25519_import_openssl should be able to handle both ed25519_pk.der and ed25519_sk.der.

I am currently short of time for coding therefore opening just an issue,

[sjaeckel]

I guess this all applies equally to x25519, right?

First, I propose replacing ed25519_set_key with:

int ed25519_import_raw(in, inlen, type, &key);

fine by me, what's the expected format of a private key then? 32 bytes of SK only or 64 bytes of PK+SK or shall both be supported?

The test vectors can be generated by: ...

these two formats you mention are already supported.

Next, I would suggest renaming ed25519_import to ed25519_import_openssl and extending it so that it can import not only public keys but also private keys produced by openssl (which is similar to what we do in ecc_import_openssl).
...
Our ed25519_import_openssl should be able to handle both ed25519_pk.der and ed25519_sk.der.

you mean ed25519_import_openssl() should additionally call ed25519_import_pkcs8()?

[karel-m]

what's the expected format of a private key then? 32 bytes of SK only or 64 bytes of PK+SK or shall both be supported?

I had in mind "32 bytes of SK only"

you mean ed25519_import_openssl() should additionally call ed25519_import_pkcs8()?

No, let us keep ed25519_import_pkcs8 separate.