Ed25519 (RFC 8032) is a signature scheme over a twisted Edwards curve
that is birationally equivalent to Curve25519. A key pair is
derived from 32 arbitrary bytes and is represented in PKCS#8 v2 format
(RFC 8410), the format also used by openssl genpkey -algorithm ed25519.
Unlike ECDSA and RSA above, Ed25519 signs the data itself rather than
a hash of it. The default encoding of Data is therefore utf8.
- [det]ed25519_new_keypair(-KeyPair)
- KeyPair is a new Ed25519 key pair, created from 32 random
bytes obtained with crypto_n_random_bytes/2.
It contains the private key and must be kept absolutely secret. See ed25519_seed_keypair/2.
- [det]ed25519_seed_keypair(+Seed,
-KeyPair)
- Deterministically derive an Ed25519 key pair from Seed, 32
arbitrary bytes. Seed can be chosen at random using
crypto_n_random_bytes/2
or derived from input keying material using crypto_data_hkdf/4.
KeyPair is a hexadecimal atom denoting the key pair in
PKCS#8 v2 format (RFC 5958, RFC 8410), the format also used by
openssl genpkey -algorithm ed25519. It contains the private
key and must be kept absolutely secret. It can be used for signing with ed25519_sign/4,
and its public key is obtained with
ed25519_keypair_public_key/2.
- [det]ed25519_keypair_public_key(+KeyPair,
-PublicKey)
- PublicKey is the public key of KeyPair, a
hexadecimal atom. The public key is used for signature verification with ed25519_verify/4
and can be shared freely.
- [det]ed25519_sign(+KeyPair,
+Data, -Signature, +Options)
- Create an Ed25519 (RFC 8032) signature for Data with the
private key of KeyPair, as created by ed25519_new_keypair/1
or obtained with load_private_key/3. Signature
is a hexadecimal atom.
Options:
- encoding(+Encoding)
- Encoding to use for Data. Default is
utf8.
Alternatives are
octet, text and hex. Note that
this differs from
ecdsa_sign/4 and rsa_sign/4,
which default to hex because they are typically applied to
a hash of the data. Ed25519 signs the data itself.
- [semidet]ed25519_verify(+PublicKey,
+Data, +Signature, +Options)
- True iff Signature can be verified as the Ed25519 signature
for
Data, using PublicKey.
Options are as for ed25519_sign/4.
