text: #ifndef SOCKETLITE_CRYPTO_CHECKSUM_H
  #define SOCKETLITE_CRYPTO_CHECKSUM_H
  #include "SL_Config.h"
  
  class SL_Crypto_Checksum
  {
  public:
      virtual int  checksum_len() = 0;
      virtual int  init() = 0;
      virtual int  update(const unsigned char *data, uint len) = 0;
      virtual int  final(unsigned char *checksum, uint len) = 0;
      virtual int  final(const unsigned char *in, uint in_len, unsigned char *out, uint out_len) = 0;
  };
  
  #endif
  
  