Command Line Interface
========================================
.. highlight:: sh

Outline
------------

The ``botan`` program is a command line tool for using a broad variety
of functions of the Botan library in the shell.

All commands follow the syntax ``botan <command> <command-options>``.

If ``botan`` is run with an unknown command, or without any command, or with the
``--help`` option, all available commands will be printed. If a particular
command is run with the ``--help`` option (like ``botan <command> --help``)
some information about the usage of the command is printed.

Starting in version 2.9, commands that take a passphrase (such as
``gen_bcrypt`` or ``pkcs8``) will also accept the literal `-` to mean
ask for the passphrase on the terminal. If supported by the operating
system, echo will be disabled while reading the passphrase.

Hash Function
----------------
``hash --algo=SHA-256 --buf-size=4096 --no-fsname files``
  Compute the *algo* digest over the data in any number of *files*. If
  no files are listed on the command line, the input source defaults
  to standard input. Unless the ``--no-fsname`` option is given, the
  filename is printed alongside the hash, in the style of tools such
  as ``sha256sum``.

Password Hash
----------------
``gen_bcrypt --work-factor=12 password``
  Calculate the bcrypt password digest of *password*. *work-factor* is an
  integer between 4 and 18.  A higher *work-factor* value results in a
  more expensive hash calculation.

``check_bcrypt password hash``
  Checks if the bcrypt hash of the passed *password* equals the passed *hash* value.

HMAC
----------------
``hmac --hash=SHA-256 --buf-size=4096 --no-fsname key files``
  Compute the HMAC tag with the cryptographic hash function *hash*
  using the key in file *key* over the data in *files*. *files*
  defaults to STDIN. Unless the ``--no-fsname`` option is given, the
  filename is printed alongside the HMAC value.

Public Key Cryptography
-------------------------------------
``keygen --algo=RSA --params= --passphrase= --pbe= --pbe-millis=300 --der-out``
  Generate a PKCS #8 *algo* private key. If *der-out* is passed, the pair is BER
  encoded.  Otherwise, PEM encoding is used. To protect the PKCS #8 formatted
  key, it is recommended to encrypt it with a provided *passphrase*. *pbe* is
  the name of the desired encryption algorithm, which uses *pbe-millis*
  milliseconds to derive the encryption key from the passed
  *passphrase*. Algorithm specific parameters, as the desired bit length of an
  RSA key, can be passed with *params*.

    - For RSA *params* specifies the bit length of the RSA modulus. It defaults to 3072.
    - For DH *params* specifies the DH parameters. It defaults to modp/ietf/2048.
    - For DSA *params* specifies the DSA parameters. It defaults to dsa/botan/2048.
    - For EC algorithms *params* specifies the elliptic curve. It defaults to secp256r1.

  The default *pbe* algorithm is "PBES2(AES-256/CBC,SHA-256)".

  With PBES2 scheme, you can select any CBC or GCM mode cipher which has an OID
  defined (such as 3DES, Camellia, SM4, Twofish or Serpent). However most other
  implementations support only AES or 3DES in CBC mode. You can also choose
  Scrypt instead of PBKDF2, by using "Scrypt" instead of the name of a hash
  function, for example "PBES2(AES-256/CBC,Scrypt)"

``pkcs8 --pass-in= --pub-out --der-out --pass-out= --pbe= --pbe-millis=300 key``
  Open a PKCS #8 formatted key at *key*. If *key* is encrypted, the passphrase
  must be passed as *pass-in*. It is possible to (re)encrypt the read key with
  the passphrase passed as *pass-out*. The parameters *pbe-millis* and *pbe*
  work similarly to ``keygen``.

``sign --der-format --passphrase= --hash=SHA-256 --emsa= key file``
  Sign the data in *file* using the PKCS #8 private key *key*. If *key* is
  encrypted, the used passphrase must be passed as *pass-in*. *emsa* specifies
  the signature scheme and *hash* the cryptographic hash function used in the
  scheme.

    - For RSA signatures EMSA4 (RSA-PSS) is the default scheme.
    - For ECDSA and DSA *emsa* defaults to EMSA1 (signing the hash directly)

  For ECDSA and DSA, the option ``--der-format`` outputs the signature as an
  ASN.1 encoded blob. Some other tools (including ``openssl``) default to this
  format.

``verify --der-format --hash=SHA-256 --emsa= pubkey file signature``
  Verify the authenticity of the data in *file* with the provided signature
  *signature* and the public key *pubkey*. Similarly to the signing process,
  *emsa* specifies the signature scheme and *hash* the cryptographic hash
  function used in the scheme.

``gen_dl_group --pbits=1024 --qbits=0 --seed= --type=subgroup``
  Generate ANSI X9.42 encoded Diffie-Hellman group parameters.

    - If *type=subgroup* is passed, the size of the prime subgroup q is sampled
      as a prime of *qbits* length and p is *pbits* long. If *qbits* is not
      passed, its length is estimated from *pbits* as described in RFC 3766.
    - If *type=strong* is passed, p is sampled as a safe prime with length
      *pbits* and the prime subgroup has size q with *pbits*-1 length.
    - If *type=dsa* is used, p and q are generated by the algorithm specified in
      FIPS 186-4. If the ``--seed`` parameter is used, it allows to select the
      seed value, instead of one being randomly generated. If the seed does not
      in fact generate a valid DSA group, the command will fail.

``dl_group_info --pem name``
  Print raw Diffie-Hellman parameters (p,g) of the standardized DH group
  *name*. If *pem* is set, the X9.42 encoded group is printed.

``ec_group_info --pem name``
  Print raw elliptic curve domain parameters of the standardized curve *name*. If
  *pem* is set, the encoded domain is printed.

``pk_encrypt --aead=AES-256/GCM rsa_pubkey datafile``
  Encrypts ``datafile`` using the specified AEAD algorithm, under a key protected
  by the specified RSA public key.

``pk_decrypt rsa_privkey datafile``
  Decrypts a file encrypted with ``pk_encrypt``. If the key is encrypted using a
  password, it will be prompted for on the terminal.

X.509
----------------------------------------------

``gen_pkcs10 key CN --country= --organization= --email= --key-pass= --hash=SHA-256  --emsa=``
  Generate a PKCS #10 certificate signing request (CSR) using the passed PKCS #8
  private key *key*. If the private key is encrypted, the decryption passphrase
  *key-pass* has to be passed.*emsa* specifies the padding scheme to be used
  when calculating the signature.

    - For RSA keys EMSA4 (RSA-PSS) is the default scheme.
    - For ECDSA, DSA, ECGDSA, ECKCDSA and GOST-34.10 keys *emsa* defaults to EMSA1.

``gen_self_signed key CN --country= --dns= --organization= --email= --key-pass= --ca --hash=SHA-256 --emsa=``
  Generate a self signed X.509 certificate using the PKCS #8 private key
  *key*. If the private key is encrypted, the decryption passphrase *key-pass*
  has to be passed. If *ca* is passed, the certificate is marked for certificate
  authority (CA) usage. *emsa* specifies the padding scheme to be used when
  calculating the signature.

    - For RSA keys EMSA4 (RSA-PSS) is the default scheme.
    - For ECDSA, DSA, ECGDSA, ECKCDSA and GOST-34.10 keys *emsa* defaults to EMSA1.

``sign_cert --ca-key-pass= --hash=SHA-256 --duration=365 --emsa= ca_cert ca_key pkcs10_req``
  Create a CA signed X.509 certificate from the information contained in the
  PKCS #10 CSR *pkcs10_req*. The CA certificate is passed as *ca_cert* and the
  respective PKCS #8 private key as *ca_key*. If the private key is encrypted,
  the decryption passphrase *ca-key-pass* has to be passed. The created
  certificate has a validity period of *duration* days. *emsa* specifies the
  padding scheme to be used when calculating the signature. *emsa* defaults to
  the padding scheme used in the CA certificate.

``ocsp_check subject issuer``
  Verify an X.509 certificate against the issuers OCSP responder. Pass the
  certificate to validate as *subject* and the CA certificate as *issuer*.

``cert_info --fingerprint --ber file``
  Parse X.509 PEM certificate and display data fields. If ``--fingerprint`` is
  used, the certificate's fingerprint is also printed.

``cert_verify subject *ca_certs``
  Verify if the provided X.509 certificate *subject* can be successfully
  validated. The list of trusted CA certificates is passed with *ca_certs*,
  which is a list of one or more certificates.

TLS Server/Client
-----------------------

``tls_ciphers --policy=default --version=tls1.2``
  Prints the list of ciphersuites that will be offered under a particular
  policy/version. The policy can be any of the the strings "default",
  "suiteb_128", "suiteb_192", "strict", or "all" to denote built-in policies, or
  it can name a file from which a policy description will be read.

``tls_client host --port=443 --print-certs --policy= --tls1.0 --tls1.1 --tls1.2 --session-db= --session-db-pass= --next-protocols= --type=tcp``
  Implements a testing TLS client, which connects to *host* via TCP or UDP on
  port *port*. The TLS version can be set with the flags *tls1.0*, *tls1.1* and
  *tls1.2* of which the lowest specified version is automatically chosen.  If
  none of the TLS version flags is set, the latest supported version is
  chosen. The client honors the TLS policy defined in the *policy* file and
  prints all certificates in the chain, if *print-certs* is passed.
  *next-protocols* is a comma separated list and specifies the protocols to
  advertise with Application-Layer Protocol Negotiation (ALPN).

``tls_server cert key --port=443 --type=tcp --policy=``
  Implements a testing TLS server, which allows TLS clients to connect. Binds to
  either TCP or UDP on port *port*. The server uses the certificate *cert* and
  the respective PKCS #8 private key *key*. The server honors the TLS policy
  defined in the *policy* file.

``tls_http_server cert key --port=443 --policy= --session-db --session-db-pass=``
  Only available if Boost.Asio support was enabled. Provides a simple HTTP server
  which replies to all requests with an informational text output. The server
  honors the TLS policy defined in the *policy* file.

``tls_proxy listen_port target_host target_port server_cert server_key``
  Only available if Boost.Asio support was enabled. Listens on a port and
  forwards all connects to a target server specified at
  ``target_host`` and ``target_port``.

Number Theory
-----------------------
``is_prime --prob=56 n``
  Test if the integer *n* is composite or prime with a Miller-Rabin primality test with *(prob+2)/2* iterations.

``factor n``
  Factor the integer *n* using a combination of trial division by small primes, and Pollard's Rho algorithm.
  It can in reasonable time factor integers up to 110 bits or so.

``gen_prime --count=1 bits``
  Samples *count* primes with a length of *bits* bits.

PSK Database
--------------------

The PSK database commands are only available if sqlite3 support was compiled in.

``psk_set db db_key name psk``
  Using the PSK database named db and encrypting under the (hex) key ``db_key``,
  save the provided psk (also hex) under ``name``::

    $ botan psk_set psk.db deadba55 bunny f00fee

``psk_get db db_key name``
  Get back a value saved with ``psk_set``::

    $ botan psk_get psk.db deadba55 bunny
    f00fee

``psk_list db db_key``
  List all values saved to the database under the given key::

    $ botan psk_list psk.db deadba55
    bunny

Secret Sharing
------------------

Split a file into several shares.

``tss_split M N data_file --id= --share-prefix=share --share-suffix=tss --hash=SHA-256``
  Split a file into ``N`` pieces any ``M`` of which suffices to
  recover the original input. The ID allows specifying a unique key ID
  which may be up to 16 bytes long, this ensures that shares can be
  uniquely matched.  If not specified a random 16 byte value is
  used. A checksum can be appended to the data to help verify correct
  recovery, this can be disabled using ``--hash=None``.

``tss_recover *shares``
  Recover some data split by ``tss_split``. If insufficient number of
  shares are provided an error is printed.

Data Encoding/Decoding
------------------------

``base64_dec file``
  Encode *file* to Base64.

``base64_enc file``
  Decode Base64 encoded *file*.

``hex_dec file``
  Encode *file* to Hex.

``hex_enc file``
  Decode Hex encoded *file*.

Miscellaneous Commands
-------------------------------------
``version --full``
  Print the version number. If option ``--full`` is provided,
  additional details are printed.

``config info_type``
  Prints build information, useful for applications which want to
  build against the library.  The ``info_type`` argument can be any of
  ``prefix``, ``cflags``, ``ldflags``, or ``libs``. This is
  similar to information provided by the ``pkg-config`` tool.

``cpuid``
  List available processor flags (aes_ni, SIMD extensions, ...).

``asn1print file``
  Decode and print *file* with ASN.1 Basic Encoding Rules (BER).

``http_get url``
  Retrieve resource from the passed http *url*.

``speed --msec=500 --provider= --buf-size=1024 algos``
  Measures the speed of the passed *algos*. If no *algos* are passed all
  available speed tests are executed. *msec* (in milliseconds) sets the period
  of measurement for each algorithm. The *buf-size* option allows testing the
  same algorithm on one or more input sizes, for example
  ``speed --buf-size=136,1500 AES-128/GCM`` tests the performance of GCM for
  small and large packet sizes.

``rng --system --rdrand bytes``
  Sample *bytes* random bytes from the specified random number generator. If
  *system* is set, the system RNG is used. If *system* is unset and *rdrand* is
  set, the hardware RDRAND instruction is used if available. If both are unset,
  HMAC_DRBG is used.

``cc_encrypt CC passphrase --tweak=``
  Encrypt the passed valid credit card number *CC* using FPE encryption and the
  passphrase *passphrase*. The key is derived from the passphrase using PBKDF2
  with SHA256. Due to the nature of FPE, the ciphertext is also a credit card
  number with a valid checksum. *tweak* is public and parameterizes the
  encryption function.

``cc_decrypt CC passphrase --tweak=``
  Decrypt the passed valid ciphertext *CC* using FPE decryption with
  the passphrase *passphrase* and the tweak *tweak*.
