sha1, SHA1Init, SHA1Update, SHA1Final - SHA-1 digest functions
cc [ flag ... ] file ... –lmd [ library ... ] #include <sha1.h> void SHA1Init(SHA1_CTX * context);
void SHA1Update(SHA1_CTX *context, const void *input,
size_t inlen);
void SHA1Final(void *output, SHA1_CTX * context);
The SHA1 functions implement the SHA-1 message-digest algorithm. The algorithm takes as input a message of arbitrary length and produces a 160-bit “fingerprint” or “message digest” as output. The SHA-1 message-digest algorithm is intended for digital signature applications in which large files are “compressed” in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA.
The SHA1Init(), SHA1Update(), and SHA1Final() functions allow a SHA-1 digest to be computed over multiple message blocks. Between blocks, the state of the SHA-1 computation is held in an SHA1_CTX context structure allocated by the caller. A complete digest computation consists of calls to SHA1 functions in the following order: one call to SHA1Init(), one or more calls to SHA1Update(), and one call to SHA1Final().
The SHA1Init() function initializes the SHA1_CTX context structure pointed to by context.
The SHA1Update() function computes a partial SHA-1 digest on the inlen-byte message block pointed to by input, and updates the SHA1_CTX context structure pointed to by context accordingly.
The SHA1Final() function generates the final SHA-1 digest, using the SHA1_CTX context structure pointed to by context. The 160-bit SHA-1 digest is written to output. After a call to SHA1Final(), the state of the context structure is undefined. It must be reinitialized with SHA1Init() before it can be used again.
The SHA-1 algorithm is believed to have some weaknesses. Migration to one of the SHA-2 or SHA-3 algorithms is highly recommended when compatibility with data formats and network protocols permit doing so. See sha2(3EXT) and sha3(3EXT) for functions which use those algorithms.
These functions do not return a value.
The following is a sample function that authenticates a message found in multiple buffers. The calling function provides an authentication buffer to contain the result of the SHA1 digest.
#include <sys/types.h>
#include <sys/uio.h>
#include <sha1.h>
int
AuthenticateMsg(unsigned char *auth_buffer, struct iovec
*messageIov, unsigned int num_buffers)
{
SHA1_CTX sha1_context;
unsigned int i;
SHA1Init(&sha1_context);
for (i = 0; i < num_buffers; i++)
{
SHA1Update(&sha1_context, messageIov->iov_base,
messageIov->iov_len);
messageIov += sizeof(struct iovec);
}
SHA1Final(auth_buffer, &sha1_context);
return 0;
}
See attributes(7) for descriptions of the following attributes:
|
sha2(3EXT), sha3(3EXT), libmd(3LIB)
Eastlake, D., RFC 3174, US Secure Hash Algorithm 1 (SHA1), September 2001. https://tools.ietf.org/html/rfc3174
These functions were added to Solaris in Solaris 10 8/07 (Update 4).