Botan: Crypto and TLS for Modern C++

Botan (Japanese for peony flower) is a C++ cryptography library released under the permissive Simplified BSD license.

Botan’s goal is to be the best option for cryptography in C++ by offering the tools necessary to implement a range of practical systems, such as TLS protocol, X.509 certificates, modern AEAD ciphers, PKCS#11 and TPM hardware support, password hashing, and post quantum crypto schemes. A Python binding is included, and several other language bindings are available. It is used in many open source and commercial products. The library is accompanied by a featureful command line interface.

See the documentation for more information about included features.

Development is coordinated on GitHub and contributions are welcome. If you need help, please open an issue on GitHub or email the botan-devel mailing list. New releases are announced on the botan-announce mailing list. If you think you have found a security issue, see the security page for contact information.

The latest release is 2.19.3 (sig), released on 2022-11-16. All releases are signed with a PGP key. See the release notes for what is new. Botan is also available through most distributions such as Fedora, Debian, Arch and Homebrew.

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Transport Layer Security (TLS) Protocol

  • TLS v1.2 and DTLS v1.2

  • Supported extensions include session tickets, SNI, ALPN, OCSP stapling, encrypt-then-mac CBC, and extended master secret.

  • Supports authentication using certificates or preshared keys (PSK)

  • Supports record encryption with ChaCha20Poly1305, AES/OCB, AES/GCM, AES/CCM, Camellia/GCM as well as legacy CBC ciphersuites.

  • Key exchange using CECPQ1, ECDH, FFDHE, or RSA

Public Key Infrastructure

  • X.509v3 certificates and CRL creation and handling

  • PKIX certificate path validation, including name constraints.

  • OCSP request creation and response handling

  • PKCS #10 certificate request generation and processing

  • Access to Windows, macOS and Unix system certificate stores

  • SQL database backed certificate store

Public Key Cryptography

  • RSA signatures and encryption

  • DH and ECDH key agreement

  • Signature schemes ECDSA, DSA, Ed25519, ECGDSA, ECKCDSA, SM2, GOST 34.10

  • Post-quantum signature scheme XMSS

  • Post-quantum key agreement schemes McEliece and NewHope

  • ElGamal encryption

  • Padding schemes OAEP, PSS, PKCS #1 v1.5, X9.31

Ciphers, hashes, MACs, and checksums

  • Authenticated cipher modes EAX, OCB, GCM, SIV, CCM, (X)ChaCha20Poly1305

  • Cipher modes CTR, CBC, XTS, CFB, OFB

  • Block ciphers AES, ARIA, Blowfish, Camellia, CAST-128, DES/3DES, IDEA, Lion, SEED, Serpent, SHACAL2, SM4, Threefish-512, Twofish

  • Stream ciphers (X)ChaCha20, (X)Salsa20, SHAKE-128, RC4

  • Hash functions SHA-1, SHA-2, SHA-3, MD5, RIPEMD-160, BLAKE2b, Skein-512, SM3, Streebog, Whirlpool

  • Authentication codes HMAC, CMAC, Poly1305, SipHash, GMAC, X9.19 DES-MAC

  • Non-cryptographic checksums Adler32, CRC24, CRC32

Other Useful Things

  • Full C++ PKCS #11 API wrapper

  • Interfaces for TPM v1.2 device access

  • Simple compression API wrapping zlib, bzip2, and lzma libraries

  • RNG wrappers for system RNG and hardware RNGs

  • HMAC_DRBG and entropy collection system for userspace RNGs

  • Password hashing schemes PBKDF2, Argon2, Scrypt, bcrypt

  • SRP-6a password authenticated key exchange

  • Key derivation functions including HKDF, KDF2, SP 800-108, SP 800-56A, SP 800-56C

  • HOTP and TOTP algorithms

  • Format preserving encryption scheme FE1

  • Threshold secret sharing

  • NIST key wrapping

  • Boost.Asio compatible TLS client stream