The German Federal Office for Information Security (BSI) carried out a project "Secure Implementation of a Universal Crypto Library" in which it analyzed open source cryptographic libraries and developed a secure cryptographic library based on the Botan cryptographic library. Botan 2.0 satisfies the basic requirements of the BSI and its use is recommended in security products. The library includes all algorithms recommended by BSI technical guidelines 02102-1, 02102-2 and 03111. Botan is licensed under the Simplified BSD license and can therefore be freely used in open source as well as commercial software.

This repository contains versions of Botan that are approved by the BSI. All changes made to Botan during the project were contributed to the original project. Our goal is to keep this fork in sync with the official repository, but we cannot assure this. In case an approved version differs from an official Botan version, the changes are listed in the release notes.

The versioning scheme used here is based on that of the original project. In case there are differences between an official release version and an approved version, the approved version number will contain the original version it is based on followed by a RSCSN suffix. For example, the version 2.4.0-RSCS1 is based on the official Botan version 2.4.0, but contains additional changes that are not part of 2.4.0 (but may be part of a future Botan version). New Botan releases will be audited on a regular basis and cryptographically relevant changes will be checked and documented. These releases will eventually be released here when approved by the BSI.

The latest version is 2.4.0-RSCS1 (sig) released on 2018-09-28.

SHA-256: EADC9A20FBE6AF4725CBA26B0636C1244083BAF4F936A129AF498D056EACBF75

All approved releases are signed with the following key:

-----BEGIN PUBLIC KEY-----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-----END PUBLIC KEY-----

The SHA-256 public key fingerprint is B1B688ED5FD24ACD53E73BE74A5279916471B2A9C80BC33AA9A7EDC58A715CF0.

Verify the release signature using Botan (where the public key listed above is referred to as Botan-Signing-Key.pem):

$ botan verify --hash=SHA-512 --emsa=EMSA4 Botan-Signing-Key.pem Cybersecurity-software-Botan-2.4.0-RSCS1.zip Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig
Signature is valid

Verify the release signature using OpenSSL (you need to base64 decode the signature first):

$ type Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig | openssl base64 -d -out Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig.dec

or alternatively using python:

$ python -m base64 -d Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig > Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig.dec

$ openssl dgst -sha512 -sigopt rsa_padding_mode:pss -sigopt rsa_pss_saltlen:64 -verify Botan-Signing-Key.pem -signature Cybersecurity-software-Botan-2.4.0-RSCS1.zip.sig.dec Cybersecurity-software-Botan-2.4.0-RSCS1.zip
Verified OK

Botan provides a comprehensive API documentation as well as a users handbook.

API documentation and the handbook for the latest version approved by the BSI can be found here:

• API documentation
• Handbook

In addition to the official documentation, we provide the following documents, which were created during the BSI project:

• Software architecture
• Implementation of cryptographic algorithms and protocols
• Specification of tests
• Test report

If you need help with a problem, please open an issue at the offical GitHub repository. In case you want to contribute some changes, please also contribute them to the official Botan repository.

Botan contains a BSI module policy which includes all algorithms recommended by BSI technical guidelines and prohibits alternative algorithms. To configure Botan with the BSI policy:

$ ./configure.py --module-policy=bsi

Additional modules which are not automatically enabled by the BSI policy can be enabled manually using --enable-modules, for example:

$ ./configure.py --module-policy=bsi --enable-modules=tls,ffi,x509,xts

Botan contains a TLS Policy class BSI_TR_02102_2 that only allows the algorithms recommended in BSI technical guideline 02102-2. This policy can be passed whereever a TLS_Policy reference is accepted by the API. For more information, see the handbook.

Botan contains an implementation of NIST SP 800-90A's HMAC_DRBG. The parameters reseed interval, maximum number of bytes per request and the entropy source(s) for seeding and reseeding can be configured per HMAC_DRBG instance. For example, a PKCS11_RNG can be used as an entropy source:

Botan::PKCS11::PKCS11_RNG p11_rng(session);
Botan::HMAC_DRBG drbg(Botan::MessageAuthenticationCode::create("HMAC(SHA-512)"), p11_rng);

HMAC_DRBG will automatically reseed whenever the reseed interval or maximum number of bytes per request are exceeded. On platforms which support fork(), it will also automatically reseed after a fork. For more information, see the handbook.