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I wanna generate a ECC key which primary key is just for cert and has 3 subkeys for auth, sign, encrypt.

I've found 2 methods to generate it. But I wanna unattended key generation via

gpg —-batch —generate-key

Work method

Interacitve mode

In contrast to --generate-key the key is generated directly without the need to answer a bunch of prompts. Unless the option --yes is given, the key creation will be canceled if the given user id already exists in the keyring. -- 4.1.3 How to manage your keys

The following command works in interacitve mode

gpg2 --expert --full-gen-key

Key info

sec   ed25519/0x5842AA66BB63DA36 2019-07-18 [C] [expires: 2020-07-17]
      Key fingerprint = FF1F E580 F6D3 453E BA88  DD98 5842 AA66 BB63 DA36
uid                   [ultimate] Name_test (Testing) <email_test@xxx.com>
ssb   ed25519/0x4F33E67F4B554A73 2019-07-18 [S] [expires: 2020-07-17]
ssb   cv25519/0xDE2253D7DAD20F1A 2019-07-18 [E] [expires: 2020-07-17]
ssb   ed25519/0x46A28F2FCC84A822 2019-07-18 [A] [expires: 2020-07-17]

Quick mode

According to

The following command works in quick mode

gpg --batch --passphrase '1Qaz@wSx' --quick-gen-key "Name_test (Testing) <email_test@xxx.com>" ed25519 cert 1y
fpr=$(gpg --list-options show-only-fpr-mbox --list-secret-keys | sed -r -n '$!d;s@^([^[:space:]]+).*@\1@g;p')

gpg --batch --pinentry-mode=loopback --passphrase '1Qaz@wSx' --quick-add-key $fpr ed25519 sign 1y
gpg --batch --pinentry-mode=loopback --passphrase '1Qaz@wSx' --quick-add-key $fpr ed25519 auth 1y
gpg --batch --pinentry-mode=loopback --passphrase '1Qaz@wSx' --quick-add-key $fpr cv25519 encrypt 1y

Key info

sec   ed25519/0xE8C6CF665ACABDB6 2019-07-18 [C] [expires: 2020-07-17]
      Key fingerprint = 03A9 E9BD CF6A BF7F 62B4  BBDA E8C6 CF66 5ACA BDB6
uid                   [ultimate] Name_test (Testing) <email_test@xxx.com>
ssb   ed25519/0xBA77943ABAE5F238 2019-07-18 [S] [expires: 2020-07-17]
ssb   ed25519/0x7272CF7C764BDB9E 2019-07-18 [A] [expires: 2020-07-17]
ssb   cv25519/0xB42F8319BA8D0CBE 2019-07-18 [E] [expires: 2020-07-17]

Unattended generation ?

I read How to batch generate ECC key, the config inside works.

Config contents

%echo Generating a OpenPGP key
Key-Type: eddsa
Key-Curve: Ed25519
Key-Usage: cert
Subkey-Type: ecdh
Subkey-Curve: Curve25519
Subkey-Usage: encrypt
Subkey-Type: eddsa
Subkey-Curve: Ed25519
Subkey-Usage: sign,auth
Passphrase: 1Qaz@wsX
Name-Real: Name_test
Name-Email: email_test@xxx.com
Name-Comment: Unattended Testing
Expire-Date: 0
%commit
%echo done

It prompts error

duplicate keyword

If I set Subkey-Usage: sign,auth,encrypt, it prompts error

specified Subkey-Usage not allowed for algo 18

This is because cv25519 for encrypt, ed25519 for cert, sign, auth.

If I just set

Subkey-Type: ecdh
Subkey-Curve: Curve25519
Subkey-Usage: encrypt

it works.

If I set

Subkey-Type: eddsa
Subkey-Curve: ed25519
Subkey-Usage: sign, auth

it also works, but sign, auth are listed in the same subkey.

How should I change the config file to make is works. Thanks.

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