From ssl-lists-owner@mincom.com Mon Sep 30 22:43:15 1996 Received: from cygnus.mincom.oz.au by orb.mincom.oz.au with SMTP id AA12802 (5.65c/IDA-1.4.4 for eay); Mon, 30 Sep 1996 12:45:43 +1000 Received: (from daemon@localhost) by cygnus.mincom.oz.au (8.7.5/8.7.3) id MAA25922 for ssl-users-outgoing; Mon, 30 Sep 1996 12:43:43 +1000 (EST) Received: from orb.mincom.oz.au (eay@orb.mincom.oz.au [192.55.197.1]) by cygnus.mincom.oz.au (8.7.5/8.7.3) with SMTP id MAA25900 for ; Mon, 30 Sep 1996 12:43:39 +1000 (EST) Received: by orb.mincom.oz.au id AA12688 (5.65c/IDA-1.4.4 for ssl-users@listserv.mincom.oz.au); Mon, 30 Sep 1996 12:43:16 +1000 Date: Mon, 30 Sep 1996 12:43:15 +1000 (EST) From: Eric Young X-Sender: eay@orb To: Sampo Kellomaki Cc: ssl-users@mincom.com, sampo@brutus.neuronio.pt Subject: Re: Signing with envelope routines In-Reply-To: <199609300037.BAA08729@brutus.neuronio.pt> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: ssl-lists-owner@mincom.com Precedence: bulk Status: O X-Status: On Mon, 30 Sep 1996, Sampo Kellomaki wrote: > I have been trying to figure out how to produce signatures with EVP_ > routines. I seem to be able to read in private key and sign some > data ok, but I can't figure out how I am supposed to read in > public key so that I could verify my signature. I use self signed > certificate. hmm... a rather poorly documented are of the library at this point in time. > I figured I should use > EVP_PKEY* pkey = PEM_ASN1_read(d2i_PrivateKey, PEM_STRING_EVP_PKEY, > fp, NULL, NULL); > to read in private key and this seems to work Ok. > > However when I try analogous > EVP_PKEY* pkey = PEM_ASN1_read(d2i_PublicKey, PEM_STRING_X509, > fp, NULL, NULL); What you should do is X509 *x509=PEM_read_X509(fp,NULL,NULL); /* which is the same as PEM_ASN1_read(d2i_X509,PEM_STRING_X509,fp, * NULL,NULL); */ Then EVP_PKEY *pkey=X509_extract_key(x509); There is also a X509_REQ_extract_key(req); which gets the public key from a certificate request. I re-worked quite a bit of this when I cleaned up the dependancy on RSA as the private key. > I figured that the second argument to PEM_ASN1_read should match the > name in my PEM encoded object, hence PEM_STRING_X509. > PEM_STRING_EVP_PKEY seems to be somehow magical > because it matches whatever private key there happens to be. I could > not find a similar constant to use with getting the certificate, however. :-), PEM_STRING_EVP_PKEY is 'magical' :-). In theory I should be using a standard such as PKCS#8 to store the private key so that the type is encoded in the asn.1 encoding of the object. > Is my approach of using PEM_ASN1_read correct? What should I pass in > as name? Can I use normal (or even self signed) X509 certificate for > verifying the signature? The actual public key is kept in the certificate, so basically you have to load the certificate and then 'unpack' the public key from the certificate. > When will SSLeay documentation be written ;-)? If I would contribute > comments to the code, would Eric take time to review them and include > them in distribution? :-) After SSLv3 and PKCS#7 :-). I actually started doing a function list but what I really need to do is do quite a few 'this is how you do xyz' type documents. I suppose the current method is to post to ssl-users and I'll respond :-). I'll add a 'demo' directory for the next release, I've appended a modified version of your program that works, you were very close :-). eric /* sign-it.cpp - Simple test app using SSLeay envelopes to sign data 29.9.1996, Sampo Kellomaki */ /* converted to C - eay :-) */ #include #include "rsa.h" #include "evp.h" #include "objects.h" #include "x509.h" #include "err.h" #include "pem.h" #include "ssl.h" void main () { int err; int sig_len; unsigned char sig_buf [4096]; static char certfile[] = "plain-cert.pem"; static char keyfile[] = "plain-key.pem"; static char data[] = "I owe you..."; EVP_MD_CTX md_ctx; EVP_PKEY * pkey; FILE * fp; X509 * x509; /* Just load the crypto library error strings, * SSL_load_error_strings() loads the crypto AND the SSL ones */ /* SSL_load_error_strings();*/ ERR_load_crypto_strings(); /* Read private key */ fp = fopen (keyfile, "r"); if (fp == NULL) exit (1); pkey = (EVP_PKEY*)PEM_ASN1_read ((char *(*)())d2i_PrivateKey, PEM_STRING_EVP_PKEY, fp, NULL, NULL); if (pkey == NULL) { ERR_print_errors_fp (stderr); exit (1); } fclose (fp); /* Do the signature */ EVP_SignInit (&md_ctx, EVP_md5()); EVP_SignUpdate (&md_ctx, data, strlen(data)); sig_len = sizeof(sig_buf); err = EVP_SignFinal (&md_ctx, sig_buf, &sig_len, pkey); if (err != 1) { ERR_print_errors_fp (stderr); exit (1); } EVP_PKEY_free (pkey); /* Read public key */ fp = fopen (certfile, "r"); if (fp == NULL) exit (1); x509 = (X509 *)PEM_ASN1_read ((char *(*)())d2i_X509, PEM_STRING_X509, fp, NULL, NULL); if (x509 == NULL) { ERR_print_errors_fp (stderr); exit (1); } fclose (fp); /* Get public key - eay */ pkey=X509_extract_key(x509); if (pkey == NULL) { ERR_print_errors_fp (stderr); exit (1); } /* Verify the signature */ EVP_VerifyInit (&md_ctx, EVP_md5()); EVP_VerifyUpdate (&md_ctx, data, strlen((char*)data)); err = EVP_VerifyFinal (&md_ctx, sig_buf, sig_len, pkey); if (err != 1) { ERR_print_errors_fp (stderr); exit (1); } EVP_PKEY_free (pkey); printf ("Signature Verified Ok.\n"); }