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-rw-r--r-- | comm/third_party/botan/src/lib/misc/fpe_fe1/fpe_fe1.h | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/misc/fpe_fe1/fpe_fe1.h b/comm/third_party/botan/src/lib/misc/fpe_fe1/fpe_fe1.h new file mode 100644 index 0000000000..d9f760f0da --- /dev/null +++ b/comm/third_party/botan/src/lib/misc/fpe_fe1/fpe_fe1.h @@ -0,0 +1,123 @@ +/* +* Format Preserving Encryption (FE1 scheme) +* (C) 2009,2018 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#ifndef BOTAN_FPE_FE1_H_ +#define BOTAN_FPE_FE1_H_ + +#include <botan/sym_algo.h> +#include <botan/bigint.h> + +namespace Botan { + +class Modular_Reducer; +class MessageAuthenticationCode; + +/** +* Format Preserving Encryption using the scheme FE1 from the paper +* "Format-Preserving Encryption" by Bellare, Rogaway, et al +* (https://eprint.iacr.org/2009/251) +*/ +class BOTAN_PUBLIC_API(2,5) FPE_FE1 final : public SymmetricAlgorithm + { + public: + + /** + * @param n the modulus. All plaintext and ciphertext values must be + * less than this. + * @param rounds the number of rounds to use. Must be at least 3. + * @param compat_mode An error in versions before 2.5.0 chose incorrect + * values for a and b. Set compat_mode to true to select this version. + * @param mac_algo the PRF to use as the encryption function + */ + FPE_FE1(const BigInt& n, + size_t rounds = 5, + bool compat_mode = false, + const std::string& mac_algo = "HMAC(SHA-256)"); + + ~FPE_FE1(); + + Key_Length_Specification key_spec() const override; + + std::string name() const override; + + void clear() override; + + /** + * Encrypt X from and onto the group Z_n using key and tweak + * @param x the plaintext to encrypt <= n + * @param tweak will modify the ciphertext + * @param tweak_len length of tweak + */ + BigInt encrypt(const BigInt& x, const uint8_t tweak[], size_t tweak_len) const; + + /** + * Decrypt X from and onto the group Z_n using key and tweak + * @param x the ciphertext to encrypt <= n + * @param tweak must match the value used to encrypt + * @param tweak_len length of tweak + */ + BigInt decrypt(const BigInt& x, const uint8_t tweak[], size_t tweak_len) const; + + BigInt encrypt(const BigInt& x, uint64_t tweak) const; + + BigInt decrypt(const BigInt& x, uint64_t tweak) const; + private: + void key_schedule(const uint8_t key[], size_t length) override; + + BigInt F(const BigInt& R, size_t round, + const secure_vector<uint8_t>& tweak, + secure_vector<uint8_t>& tmp) const; + + secure_vector<uint8_t> compute_tweak_mac(const uint8_t tweak[], size_t tweak_len) const; + + std::unique_ptr<MessageAuthenticationCode> m_mac; + std::unique_ptr<Modular_Reducer> mod_a; + std::vector<uint8_t> m_n_bytes; + BigInt m_a; + BigInt m_b; + size_t m_rounds; + }; + +namespace FPE { + +/** +* Format Preserving Encryption using the scheme FE1 from the paper +* "Format-Preserving Encryption" by Bellare, Rogaway, et al +* (https://eprint.iacr.org/2009/251) +* +* Encrypt X from and onto the group Z_n using key and tweak +* @param n the modulus +* @param X the plaintext as a BigInt +* @param key a random key +* @param tweak will modify the ciphertext (think of as an IV) +* +* @warning This function is hardcoded to use only 3 rounds which +* may be insecure for some values of n. Prefer FPE_FE1 class +*/ +BigInt BOTAN_PUBLIC_API(2,0) fe1_encrypt(const BigInt& n, const BigInt& X, + const SymmetricKey& key, + const std::vector<uint8_t>& tweak); + +/** +* Decrypt X from and onto the group Z_n using key and tweak +* @param n the modulus +* @param X the ciphertext as a BigInt +* @param key is the key used for encryption +* @param tweak the same tweak used for encryption +* +* @warning This function is hardcoded to use only 3 rounds which +* may be insecure for some values of n. Prefer FPE_FE1 class +*/ +BigInt BOTAN_PUBLIC_API(2,0) fe1_decrypt(const BigInt& n, const BigInt& X, + const SymmetricKey& key, + const std::vector<uint8_t>& tweak); + +} + +} + +#endif |