diff options
author | lloyd <[email protected]> | 2015-02-05 07:44:25 +0000 |
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committer | lloyd <[email protected]> | 2015-02-05 07:44:25 +0000 |
commit | cb0f83ae63c4555cbdd0607e3a5f6e9260c0d19c (patch) | |
tree | 4981027a25fa8074177b97c3a3ca7431f3337deb /src/lib/misc/cryptobox/cryptobox.cpp | |
parent | 2c14faf0aa1cfe0f8d70af1938dcad5b4d6d3b59 (diff) |
Clean up root dir, remove some unneeded dependencies
Diffstat (limited to 'src/lib/misc/cryptobox/cryptobox.cpp')
-rw-r--r-- | src/lib/misc/cryptobox/cryptobox.cpp | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/lib/misc/cryptobox/cryptobox.cpp b/src/lib/misc/cryptobox/cryptobox.cpp new file mode 100644 index 000000000..fb210bc0b --- /dev/null +++ b/src/lib/misc/cryptobox/cryptobox.cpp @@ -0,0 +1,163 @@ +/* +* Cryptobox Message Routines +* (C) 2009 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/cryptobox.h> +#include <botan/filters.h> +#include <botan/pipe.h> +#include <botan/lookup.h> +#include <botan/sha2_64.h> +#include <botan/hmac.h> +#include <botan/pbkdf2.h> +#include <botan/pem.h> +#include <botan/get_byte.h> +#include <botan/mem_ops.h> + +namespace Botan { + +namespace CryptoBox { + +namespace { + +/* +First 24 bits of SHA-256("Botan Cryptobox"), followed by 8 0 bits +for later use as flags, etc if needed +*/ +const u32bit CRYPTOBOX_VERSION_CODE = 0xEFC22400; + +const size_t VERSION_CODE_LEN = 4; +const size_t CIPHER_KEY_LEN = 32; +const size_t CIPHER_IV_LEN = 16; +const size_t MAC_KEY_LEN = 32; +const size_t MAC_OUTPUT_LEN = 20; +const size_t PBKDF_SALT_LEN = 10; +const size_t PBKDF_ITERATIONS = 8 * 1024; + +const size_t PBKDF_OUTPUT_LEN = CIPHER_KEY_LEN + CIPHER_IV_LEN + MAC_KEY_LEN; + +} + +std::string encrypt(const byte input[], size_t input_len, + const std::string& passphrase, + RandomNumberGenerator& rng) + { + secure_vector<byte> pbkdf_salt(PBKDF_SALT_LEN); + rng.randomize(&pbkdf_salt[0], pbkdf_salt.size()); + + PKCS5_PBKDF2 pbkdf(new HMAC(new SHA_512)); + + OctetString master_key = pbkdf.derive_key( + PBKDF_OUTPUT_LEN, + passphrase, + &pbkdf_salt[0], + pbkdf_salt.size(), + PBKDF_ITERATIONS); + + const byte* mk = master_key.begin(); + + SymmetricKey cipher_key(&mk[0], CIPHER_KEY_LEN); + SymmetricKey mac_key(&mk[CIPHER_KEY_LEN], MAC_KEY_LEN); + InitializationVector iv(&mk[CIPHER_KEY_LEN + MAC_KEY_LEN], CIPHER_IV_LEN); + + Pipe pipe(get_cipher("Serpent/CTR-BE", cipher_key, iv, ENCRYPTION), + new Fork( + nullptr, + new MAC_Filter(new HMAC(new SHA_512), + mac_key, MAC_OUTPUT_LEN))); + + pipe.process_msg(input, input_len); + + /* + Output format is: + version # (4 bytes) + salt (10 bytes) + mac (20 bytes) + ciphertext + */ + const size_t ciphertext_len = pipe.remaining(0); + + std::vector<byte> out_buf(VERSION_CODE_LEN + + PBKDF_SALT_LEN + + MAC_OUTPUT_LEN + + ciphertext_len); + + for(size_t i = 0; i != VERSION_CODE_LEN; ++i) + out_buf[i] = get_byte(i, CRYPTOBOX_VERSION_CODE); + + copy_mem(&out_buf[VERSION_CODE_LEN], &pbkdf_salt[0], PBKDF_SALT_LEN); + + pipe.read(&out_buf[VERSION_CODE_LEN + PBKDF_SALT_LEN], MAC_OUTPUT_LEN, 1); + pipe.read(&out_buf[VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN], + ciphertext_len, 0); + + return PEM_Code::encode(out_buf, "BOTAN CRYPTOBOX MESSAGE"); + } + +std::string decrypt(const byte input[], size_t input_len, + const std::string& passphrase) + { + DataSource_Memory input_src(input, input_len); + secure_vector<byte> ciphertext = + PEM_Code::decode_check_label(input_src, + "BOTAN CRYPTOBOX MESSAGE"); + + if(ciphertext.size() < (VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN)) + throw Decoding_Error("Invalid CryptoBox input"); + + for(size_t i = 0; i != VERSION_CODE_LEN; ++i) + if(ciphertext[i] != get_byte(i, CRYPTOBOX_VERSION_CODE)) + throw Decoding_Error("Bad CryptoBox version"); + + const byte* pbkdf_salt = &ciphertext[VERSION_CODE_LEN]; + + PKCS5_PBKDF2 pbkdf(new HMAC(new SHA_512)); + + OctetString master_key = pbkdf.derive_key( + PBKDF_OUTPUT_LEN, + passphrase, + pbkdf_salt, + PBKDF_SALT_LEN, + PBKDF_ITERATIONS); + + const byte* mk = master_key.begin(); + + SymmetricKey cipher_key(&mk[0], CIPHER_KEY_LEN); + SymmetricKey mac_key(&mk[CIPHER_KEY_LEN], MAC_KEY_LEN); + InitializationVector iv(&mk[CIPHER_KEY_LEN + MAC_KEY_LEN], CIPHER_IV_LEN); + + Pipe pipe(new Fork( + get_cipher("Serpent/CTR-BE", cipher_key, iv, DECRYPTION), + new MAC_Filter(new HMAC(new SHA_512), + mac_key, MAC_OUTPUT_LEN))); + + const size_t ciphertext_offset = + VERSION_CODE_LEN + PBKDF_SALT_LEN + MAC_OUTPUT_LEN; + + pipe.process_msg(&ciphertext[ciphertext_offset], + ciphertext.size() - ciphertext_offset); + + byte computed_mac[MAC_OUTPUT_LEN]; + pipe.read(computed_mac, MAC_OUTPUT_LEN, 1); + + if(!same_mem(computed_mac, + &ciphertext[VERSION_CODE_LEN + PBKDF_SALT_LEN], + MAC_OUTPUT_LEN)) + throw Decoding_Error("CryptoBox integrity failure"); + + return pipe.read_all_as_string(0); + } + +std::string decrypt(const std::string& input, + const std::string& passphrase) + { + return decrypt(reinterpret_cast<const byte*>(&input[0]), + input.size(), + passphrase); + } + +} + +} |