sha1example.c

#include <openssl/evp.h>

unsigned char *
sha1digest(unsigned char *buf, unsigned int len, unsigned int *olen)
{
    EVP_MD_CTX ctx;
    const EVP_MD *md;
    unsigned char *retval;

    if (buf == NULL) {
        return NULL;        // XXX NEED BETTER ERROR PROPAGATION
    }
    
    md = EVP_sha1();
    if (md == NULL)
        return NULL;        // XXX NEED BETTER ERROR PROPAGATION
	
	retval = malloc(EVP_MAX_MD_SIZE);
	if (retval == NULL)
        return NULL;        // XXX NEED BETTER ERROR PROPAGATION
	
	EVP_DigestInit(&ctx, md);
	EVP_DigestUpdate(&ctx, buf, len);
	EVP_DigestFinal(&ctx, retval, olen);
    return retval;
}