When there are multiple signing keys, snapcraft sign-build shows a wizard-like text and lets you enter a number to select the key you want. snapcraft validate instead uses the default key. I'm not sure what's the right behaviour, but they should be consistent. $ snapcraft list-keys Name SHA3-384 fingerprint * default pvqbQVTvSgeMIuUXyr0d_4O_DLQNUDitvmficJ66KYcn_qZKDZcBT6XbgRm7Dcwb * test 5bsceVZqUkv01S4PxD10guWHQqvCNS7Mwv-I_U089NbcLhC-hnQ78zMGQGr9IZFN $ snapcraft validate u1test20161026 ubuntu-core=4 Getting details for ubuntu-core Signing validation ubuntu-core=4 You need a passphrase to unlock the secret key for user: "default" 4096-bit RSA key, ID D017FEB3, created 2016-01-01 $ snapcraft sign-build *.snap Select a key: Number Name SHA3-384 fingerprint 1 default pvqbQVTvSgeMIuUXyr0d_4O_DLQNUDitvmficJ66KYcn_qZKDZcBT6XbgRm7Dcwb 2 test 5bsceVZqUkv01S4PxD10guWHQqvCNS7Mwv-I_U089NbcLhC-hnQ78zMGQGr9IZFN Key number: 1 You need a passphrase to unlock the secret key for user: "default" 4096-bit RSA key, ID D017FEB3, created 2016-01-01