sha1_final(3openssl) [opensolaris man page]

sha(3openssl)							      OpenSSL							     sha(3openssl)

NAME

       SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm

SYNOPSIS

	#include <openssl/sha.h>

	unsigned char *SHA1(const unsigned char *d, unsigned long n,
			 unsigned char *md);

	void SHA1_Init(SHA_CTX *c);
	void SHA1_Update(SHA_CTX *c, const void *data,
			 unsigned long len);
	void SHA1_Final(unsigned char *md, SHA_CTX *c);

DESCRIPTION

       SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 160 bit output.

       SHA1() computes the SHA-1 message digest of the n bytes at d and places it in md (which must have space for SHA_DIGEST_LENGTH == 20 bytes
       of output). If md is NULL, the digest is placed in a static array.

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

       SHA1_Init() initializes a SHA_CTX 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 SHA_DIGEST_LENGTH == 20 bytes of output, and erases the SHA_CTX.

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

       The predecessor of SHA-1, SHA, is also implemented, but it should be used only when backward compatibility is required.

RETURN VALUES

       SHA1() returns a pointer to the hash value.

       SHA1_Init(), SHA1_Update() and SHA1_Final() do not return values.

CONFORMING TO

       SHA: US Federal Information Processing Standard FIPS PUB 180 (Secure Hash Standard), SHA-1: US Federal Information Processing Standard FIPS
       PUB 180-1 (Secure Hash Standard), ANSI X9.30

SEE ALSO

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

HISTORY

       SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all versions of SSLeay and OpenSSL.

OpenSSL-0.9.8							    Oct 11 2005 						     sha(3openssl)

SHA(3)							   BSD Library Functions Manual 						    SHA(3)

NAME

     SHA_Init, SHA_Update, SHA_Final, SHA_End, SHA_File, SHA_FileChunk, SHA_Data, SHA1_Init, SHA1_Update, SHA1_Final, SHA1_End, SHA1_File,
     SHA1_FileChunk, SHA1_Data -- calculate the FIPS 160 and 160-1 ``SHA'' message digests

LIBRARY

     Message Digest (MD4, MD5, etc.) Support Library (libmd, -lmd)

SYNOPSIS

     #include <sys/types.h>
     #include <sha.h>

     void
     SHA_Init(SHA_CTX *context);

     void
     SHA_Update(SHA_CTX *context, const unsigned char *data, size_t len);

     void
     SHA_Final(unsigned char digest[20], SHA_CTX *context);

     char *
     SHA_End(SHA_CTX *context, char *buf);

     char *
     SHA_File(const char *filename, char *buf);

     char *
     SHA_FileChunk(const char *filename, char *buf, off_t offset, off_t length);

     char *
     SHA_Data(const unsigned char *data, unsigned int len, char *buf);

     void
     SHA1_Init(SHA_CTX *context);

     void
     SHA1_Update(SHA_CTX *context, const unsigned char *data, size_t len);

     void
     SHA1_Final(unsigned char digest[20], SHA_CTX *context);

     char *
     SHA1_End(SHA_CTX *context, char *buf);

     char *
     SHA1_File(const char *filename, char *buf);

     char *
     SHA1_FileChunk(const char *filename, char *buf, off_t offset, off_t length);

     char *
     SHA1_Data(const unsigned char *data, unsigned int len, char *buf);

DESCRIPTION

     The SHA_ and SHA1_ functions calculate a 160-bit cryptographic checksum (digest) for any number of input bytes.  A cryptographic checksum is
     a one-way hash function; that is, it is computationally impractical to find the input corresponding to a particular output.  This net result
     is a ``fingerprint'' of the input-data, which does not disclose the actual input.

     SHA (or SHA-0) is the original Secure Hash Algorithm specified in FIPS 160.  It was quickly proven insecure, and has been superseded by
     SHA-1.  SHA-0 is included for compatibility purposes only.

     The SHA1_Init(), SHA1_Update(), and SHA1_Final() functions are the core functions.  Allocate an SHA_CTX, initialize it with SHA1_Init(), run
     over the data with SHA1_Update(), and finally extract the result using SHA1_Final().

     SHA1_End() is a wrapper for SHA1_Final() which converts the return value to a 41-character (including the terminating '') ASCII string
     which represents the 160 bits in hexadecimal.

     SHA1_File() calculates the digest of a file, and uses SHA1_End() to return the result.  If the file cannot be opened, a null pointer is
     returned.	SHA1_FileChunk() is similar to SHA1_File(), but it only calculates the digest over a byte-range of the file specified, starting at
     offset and spanning length bytes.	If the length parameter is specified as 0, or more than the length of the remaining part of the file,
     SHA1_FileChunk() calculates the digest from offset to the end of file.  SHA1_Data() calculates the digest of a chunk of data in memory, and
     uses SHA1_End() to return the result.

     When using SHA1_End(), SHA1_File(), or SHA1_Data(), the buf argument can be a null pointer, in which case the returned string is allocated
     with malloc(3) and subsequently must be explicitly deallocated using free(3) after use.  If the buf argument is non-null it must point to at
     least 41 characters of buffer space.

SEE ALSO

     md4(3), md5(3), ripemd(3), sha256(3)

HISTORY

     These functions appeared in FreeBSD 4.0.

AUTHORS

     The core hash routines were implemented by Eric Young based on the published FIPS standards.

BUGS

     No method is known to exist which finds two files having the same hash value, nor to find a file with a specific hash value.  There is on the
     other hand no guarantee that such a method does not exist.

     The IA32 (Intel) implementation of SHA-1 makes heavy use of the 'bswapl' instruction, which is not present on the original 80386.	Attempts
     to use SHA-1 on those processors will cause an illegal instruction trap.  (Arguably, the kernel should simply emulate this instruction.)

BSD
								  March 28, 2014							       BSD