Command Line Interface


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.

Most arguments that take a path to a file will also accept the literal - to mean the file content should be read from STDIN instead.

Hash Function

hash --algo=SHA-256 --buf-size=4096 --no-fsname --format=hex *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_argon2 --mem=65536 --p=1 --t=1 password

Calculate the Argon2 password digest of password. mem is the amount of memory to use in Kb, p the parallelization parameter and t the number of iterations to use.

check_argon2 password hash

Checks if the Argon2 hash of the passed password equals the passed hash value.

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.

pbkdf_tune --algo=Scrypt --max-mem=256 --output-len=32 --check *times

Tunes the PBKDF algorithm specified with --algo= for the given times.


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.


cipher --buf-size=4096 --decrypt --cipher= --key= --nonce= --ad=

Encrypt a given file with the specified cipher, eg “AES-256/GCM”. If --decrypt is provided the file is decrypted instead.

Public Key Cryptography

keygen --algo=RSA --params= --passphrase= --pbe= --pbe-millis=300 --provider= --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)”. Scrypt is also supported by some other implementations including OpenSSL.

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= --provider= 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.

The signature is formatted for your screen using base64.

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.

fingerprint --no-fsname --algo=SHA-256 *keys

Calculate the public key fingerprint of the keys.

pk_workfactor --type=rsa bits

Provide an estimate of the strength of a public key based on it’s size. --type= can be “rsa”, “dl” or “dl_exp”.


gen_pkcs10 key CN --country= --organization= --ca --path-limit=1 --email= --dns= --ext-ku= --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= --path-limit=1 --days=365 --key-pass= --ca --hash=SHA-256 --emsa= --der

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 --timeout=3000 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 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.

trust_roots --dn --dn-only --display

List the certificates in the system trust store.

TLS Server/Client

The --policy= argument of the TLS commands specifies the TLS policy to use. The policy can be any of the strings “default”, “suiteb_128”, “suiteb_192”, “bsi”, “strict”, or “all” to denote built-in policies, or it can name a file from which a policy description will be read.

tls_ciphers --policy=default --version=tls1.2

Prints the list of ciphersuites that will be offered under a particular policy/version.

tls_client host --port=443 --print-certs --policy=default --tls1.0 --tls1.1 --tls1.2 --skip-system-cert-store --trusted-cas= --session-db= --session-db-pass= --next-protocols= --type=tcp --client-cert= --client-cert-key=

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 specified with policy 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). Pass a path to a client certificate PEM and unencrypted PKCS8 encoded private key if client authentication is required.

tls_server cert key --port=443 --type=tcp --policy=default --dump-traces= --max-clients=0 --socket-id=0

Implements a testing TLS server, which allows TLS clients to connect and which echos any data that is sent to it. 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 specified with policy. socket-id is only available on FreeBSD and sets the so_user_cookie value of the used socket.

tls_http_server cert key --port=443 --policy=default --threads=0 --max-clients=0 --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 specified with policy.

tls_proxy listen_port target_host target_port server_cert server_key--policy=default --threads=0 --max-clients=0 --session-db= --session-db-pass=

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.

tls_client_hello --hex input

Parse and print a TLS client hello message.

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.

mod_inverse n mod

Calculates a modular inverse.

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
psk_list db db_key

List all values saved to the database under the given key:

$ botan psk_list psk.db deadba55

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

base32_dec file

Decode file to Base32.

base32_enc file

Encode Base32 encoded file.

base58_enc --check file

Encode file to Base58. If --check is provided Base58Check is used.

base58_dec --check file

Decode Base58 encoded file. If --check is provided Base58Check is used.

base64_dec file

Decode file to Base64.

base64_enc file

Encode Base64 encoded file.

hex_dec file

Decode file to Hex.

hex_enc file

Encode Hex encoded file.

Forward Error Correction

fec_encode --suffix=fec --prefix= --output-dir= k n input

Split a given input file into n shares where k shares are required to recreate the original file. The output shares a written to files with the file extension specified in --suffix and either the original file name or the one specified in --prefix. The output directory is either equal to the input file’s directory or the one specified in --output-dir.

fec_decode *shares

If given enough shares, this will output the original input file’s content to stdout. Otherwise an error is printed on stderr.

fec_info share

Given a single share this will print information about the share. For instance: FEC share 4/4 with 3 needed for recovery

Miscellaneous Commands

version --full

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

has_command cmd

Test if the command cmd is available.

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.


List available processor flags (AES-NI, SIMD extensions, …).

cpu_clock --test-duration=500

Estimate the speed of the CPU cycle counter.

asn1print --skip-context-specific --print-limit=4096 --bin-limit=2048 --max-depth=64 --pem file`

Decode and print file with ASN.1 Basic Encoding Rules (BER). If flag --pem is used, or the filename ends in .pem, then PEM encoding is assumed. Otherwise the input is assumed to be binary DER/BER.

http_get --redirects=1 --timeout=3000 url

Retrieve resource from the passed http url.

speed --msec=500 --format=default --ecc-groups= --provider= --buf-size=1024 --clear-cpuid= --cpu-clock-speed=0 --cpu-clock-ratio=1.0 *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. format can be “default”, “table” or “json”.

timing_test test_type --test-data-file= --test-data-dir=src/tests/data/timing --warmup-runs=1000 --measurement-runs=10000

Run various timing side channel tests.

rng --format=hex --system --rdrand --auto --entropy --drbg --drbg-seed= *bytes

Sample bytes random bytes from the specified random number generator. If system is set, the system RNG is used. If rdrand is set, the hardware RDRAND instruction is used. If auto is set, AutoSeeded_RNG is used, seeded with the system RNG if available or the global entropy source otherwise. If entropy is set, AutoSeeded_RNG is used, seeded with the global entropy source. If drbg is set, HMAC_DRBG is used seeded with drbg-seed.

entropy --truncate-at=128 source

Sample a raw entropy source.

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.

roughtime_check --raw-time chain-file

Parse and validate a Roughtime chain file.

roughtime --raw-time --chain-file=roughtime-chain --max-chain-size=128 --check-local-clock=60 --host= --pubkey= --servers-file=

Retrieve time from a Roughtime server and store it in a chain file.


Generate and print a random UUID.

compress --type=gzip --level=6 --buf-size=8192 file

Compress a given file.

decompress --buf-size=8192 file

Decompress a given compressed archive.