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    fido2-cred

    FIDO2-CRED(1) General Commands Manual FIDO2-CRED(1)

    fido2-cred —
    make/verify a FIDO2 credential

    fido2-cred -M [
    -bdhqruvw
    ] [
    -c cred_protect
    ] [
    -i input_file
    ] [
    -o output_file
    ] device [
    type
    ]

    fido2-cred -V [
    -dhv
    ] [
    -c cred_protect
    ] [
    -i input_file
    ] [
    -o output_file
    ] [
    type
    ]

    fido2-cred makes or verifies a FIDO2 credential.
    A credential type may be es256 (denoting ECDSA over NIST P-256 with SHA-256), rs256 (denoting 2048-bit RSA with PKCS#1.5 padding and SHA-256), or eddsa (denoting EDDSA over Curve25519 with SHA-512). If type is not specified, es256 is assumed.
    When making a credential, the authenticator may require the user to authenticate with a PIN. If the -q option is not specified, fido2-cred will prompt the user for the PIN. If a tty is available, fido2-cred will use it to obtain the PIN. Otherwise, stdin is used.
    The input of fido2-cred is defined by the parameters of the credential to be made/verified. See the INPUT FORMAT section for details.
    The output of fido2-cred is defined by the result of the selected operation. See the OUTPUT FORMAT section for details.
    If a credential is successfully created or verified, fido2-cred exits 0. Otherwise, fido2-cred exits 1.
    The options are as follows:
    Tells fido2-cred to make a new credential on device.
    Tells fido2-cred to verify a credential.
    Request the credential's “largeBlobKey”, a 32-byte symmetric key associated with the generated credential.
    cred_protect
    If making a credential, set the credential's protection level to cred_protect, where cred_protect is the credential's protection level in decimal notation. Please refer to <fido/param.h> for the set of possible values. If verifying a credential, check whether the credential's protection level was signed by the authenticator as cred_protect.
    Causes fido2-cred to emit debugging output on stderr.
    If making a credential, enable the FIDO2 hmac-secret extension. If verifying a credential, check whether the extension data bit was signed by the authenticator.
    input_file
    Tells fido2-cred to read the parameters of the credential from input_file instead of stdin.
    output_file
    Tells fido2-cred to write output on output_file instead of stdout.
    Tells fido2-cred to be quiet. If a PIN is required and -q is specified, fido2-cred will fail.
    Create a resident credential. Resident credentials are called “discoverable credentials” in CTAP 2.1.
    Create a U2F credential. By default, fido2-cred will use FIDO2 if supported by the authenticator, and fallback to U2F otherwise.
    If making a credential, request user verification. If verifying a credential, check whether the user verification bit was signed by the authenticator.
    Tells fido2-cred that the first line of input when making a credential shall be interpreted as unhashed client data. This is required by Windows Hello, which calculates the client data hash internally.

    The input of fido2-cred consists of base64 blobs and UTF-8 strings separated by newline characters ('\n').
    When making a credential, fido2-cred expects its input to consist of:
    1. client data hash (base64 blob);
    2. relying party id (UTF-8 string);
    3. user name (UTF-8 string);
    4. user id (base64 blob).
    When verifying a credential, fido2-cred expects its input to consist of:
    1. client data hash (base64 blob);
    2. relying party id (UTF-8 string);
    3. credential format (UTF-8 string);
    4. authenticator data (base64 blob);
    5. credential id (base64 blob);
    6. attestation signature (base64 blob);
    7. attestation certificate (optional, base64 blob).
    UTF-8 strings passed to fido2-cred must not contain embedded newline or NUL characters.

    The output of fido2-cred consists of base64 blobs, UTF-8 strings, and PEM-encoded public keys separated by newline characters ('\n').
    Upon the successful generation of a credential, fido2-cred outputs:
    1. client data hash (base64 blob);
    2. relying party id (UTF-8 string);
    3. credential format (UTF-8 string);
    4. authenticator data (base64 blob);
    5. credential id (base64 blob);
    6. attestation signature (base64 blob);
    7. attestation certificate, if present (base64 blob).
    8. the credential's associated 32-byte symmetric key (“largeBlobKey”), if present (base64 blob).
    Upon the successful verification of a credential, fido2-cred outputs:
    1. credential id (base64 blob);
    2. PEM-encoded credential key.

    Create a new es256 credential on /dev/hidraw5, verify it, and save the id and the public key of the credential in cred:
    $ echo credential challenge | openssl sha256 -binary | base64 > cred_param
    $ echo relying party >> cred_param
    $ echo user name >> cred_param
    $ dd if=/dev/urandom bs=1 count=32 | base64 >> cred_param
    $ fido2-cred -M -i cred_param /dev/hidraw5 | fido2-cred -V -o cred

    fido2-assert(1), fido2-token(1)

    Please note that fido2-cred handles Basic Attestation and Self Attestation transparently. In the case of Basic Attestation, the validity of the authenticator's attestation certificate is not verified.
    July 3, 2023 Debian