text: /*********************************************************************
  * Filename:   sha256.h
  * Author:     Brad Conte (brad AT bradconte.com)
  * Copyright:
  * Disclaimer: This code is presented "as is" without any guarantees.
  * Details:    Defines the API for the corresponding SHA1 implementation.
  *********************************************************************/
  
  #ifndef SHA256_H
  #define SHA256_H
  
  /*************************** HEADER FILES ***************************/
  #include <stddef.h>
  #include <stdint.h>
  
  /****************************** MACROS ******************************/
  #define SHA256_BLOCK_SIZE 32            // SHA256 outputs a 32 byte digest
  
  /**************************** DATA TYPES ****************************/
  
  typedef struct {
  	uint8_t data[64];
  	uint32_t datalen;
  	unsigned long long bitlen;
  	uint32_t state[8];
  } SHA256_CTX;
  
  /*********************** FUNCTION DECLARATIONS **********************/
  void sha256_init(SHA256_CTX *ctx);
  void sha256_update(SHA256_CTX *ctx, const uint8_t data[], size_t len);
  void sha256_final(SHA256_CTX *ctx, uint8_t hash[]);
  void sha256(const char *in, char *out, int len);
  
  #endif   // SHA256_H
  