SHA256_Init (3)

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NAME

SHA1, SHA1_Init, SHA1_Update, SHA1_Final, SHA224, SHA224_Init, SHA224_Update, SHA224_Final, SHA256, SHA256_Init, SHA256_Update, SHA256_Final, SHA384, SHA384_Init, SHA384_Update, SHA384_Final, SHA512, SHA512_Init, SHA512_Update, SHA512_Final - Secure Hash Algorithm

SYNOPSIS

 #include <openssl/sha.h>

 int SHA1_Init(SHA_CTX *c);
 int SHA1_Update(SHA_CTX *c, const void *data, size_t len);
 int SHA1_Final(unsigned char *md, SHA_CTX *c);
 unsigned char *SHA1(const unsigned char *d, size_t n,
      unsigned char *md);

 int SHA224_Init(SHA256_CTX *c);
 int SHA224_Update(SHA256_CTX *c, const void *data, size_t len);
 int SHA224_Final(unsigned char *md, SHA256_CTX *c);
 unsigned char *SHA224(const unsigned char *d, size_t n,
      unsigned char *md);

 int SHA256_Init(SHA256_CTX *c);
 int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
 int SHA256_Final(unsigned char *md, SHA256_CTX *c);
 unsigned char *SHA256(const unsigned char *d, size_t n,
      unsigned char *md);

 int SHA384_Init(SHA512_CTX *c);
 int SHA384_Update(SHA512_CTX *c, const void *data, size_t len);
 int SHA384_Final(unsigned char *md, SHA512_CTX *c);
 unsigned char *SHA384(const unsigned char *d, size_t n,
      unsigned char *md);

 int SHA512_Init(SHA512_CTX *c);
 int SHA512_Update(SHA512_CTX *c, const void *data, size_t len);
 int SHA512_Final(unsigned char *md, SHA512_CTX *c);
 unsigned char *SHA512(const unsigned char *d, size_t n,
      unsigned char *md);

DESCRIPTION

Applications should use the higher level functions EVP_DigestInit(3) etc. instead of calling the hash functions directly.

(Secure Hash Algorithm) is a cryptographic hash function with a 160 bit output.

() computes the message digest of the n bytes at d and places it in md (which must have space for == 20 bytes of output). If md is the digest is placed in a static array. Note: setting md to is not thread safe.

The following functions may be used if the message is not completely stored in memory:

SHA1_Init() initializes a

structure.

SHA1_Update() can be called repeatedly with chunks of the message to be hashed (len bytes at data).

SHA1_Final() places the message digest in md, which must have space for

== 20 bytes of output, and erases the .

The

and families of functions operate in the same way as for the functions. Note that and use a object instead of . and use . The buffer md must have space for the output from the variant being used (defined by and ). Also note that, as for the () function above, the (), (), () and () functions are not thread safe if md is

The predecessor of

is also implemented, but it should be used only when backward compatibility is required.

RETURN VALUES

(), (), (), () and () return a pointer to the hash value.

SHA1_Init(), SHA1_Update() and SHA1_Final() and equivalent

and functions return 1 for success, 0 otherwise.

CONFORMING TO

Federal Information Processing Standard (Secure Hash Standard),

SEE ALSO

ripemd(3), hmac(3), EVP_DigestInit(3)

HISTORY

(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all versions of SSLeay and OpenSSL.