Files
git-crypt/crypto.hpp
2012-07-06 15:38:40 -07:00

40 lines
1.1 KiB
C++

#ifndef _CRYPTO_H
#define _CRYPTO_H
#include <openssl/aes.h>
#include <stdint.h>
#include <stddef.h>
#include <iosfwd>
enum {
HMAC_KEY_LEN = 64,
AES_KEY_BITS = 256,
MAX_CRYPT_BYTES = (1ULL<<32)*16 // Don't encrypt more than this or the CTR value will repeat itself
};
struct keys_t {
AES_KEY enc;
uint8_t hmac[HMAC_KEY_LEN];
};
void load_keys (const char* filepath, keys_t* keys);
class aes_ctr_state {
char nonce[12]; // First 96 bits of counter
uint32_t byte_counter; // How many bytes processed so far?
uint8_t otp[16]; // The current OTP that's in use
public:
aes_ctr_state (const uint8_t* arg_nonce, size_t arg_nonce_len);
void process_block (const AES_KEY* key, const uint8_t* in, uint8_t* out, size_t len);
};
// Compute HMAC-SHA1-96 (i.e. first 96 bits of HMAC-SHA1) for the given buffer with the given key
void hmac_sha1_96 (uint8_t* out, const uint8_t* buffer, size_t buffer_len, const uint8_t* key, size_t key_len);
// Encrypt/decrypt an entire input stream, writing to the given output stream
void process_stream (std::istream& in, std::ostream& out, const AES_KEY* enc_key, const uint8_t* nonce);
#endif