diff --git a/dsa.c b/dsa.c
new file mode 100644
index 0000000..1594c14
--- /dev/null
+++ b/dsa.c
@@ -0,0 +1,298 @@
+/*
+ * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Markus Friedl.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+RCSID("$Id: dsa.c,v 1.4 2000/04/14 10:30:31 markus Exp $");
+
+#include "ssh.h"
+#include "xmalloc.h"
+#include "buffer.h"
+#include "bufaux.h"
+#include "compat.h"
+
+#include <openssl/bn.h>
+#include <openssl/dh.h>
+#include <openssl/rsa.h>
+#include <openssl/dsa.h>
+#include <openssl/evp.h>
+#include <openssl/bio.h>
+#include <openssl/pem.h>
+
+#include <openssl/hmac.h>
+#include "kex.h"
+#include "key.h"
+
+#define INTBLOB_LEN	20
+#define SIGBLOB_LEN	(2*INTBLOB_LEN)
+
+Key *
+dsa_serverkey_from_blob(
+    char *serverhostkey, int serverhostkeylen)
+{
+	Buffer b;
+	char *ktype;
+	int rlen;
+	DSA *dsa;
+	Key *key;
+
+	/* fetch & parse DSA/DSS pubkey */
+	key = key_new(KEY_DSA);
+	dsa = key->dsa;
+	buffer_init(&b);
+	buffer_append(&b, serverhostkey, serverhostkeylen);
+	ktype = buffer_get_string(&b, NULL);
+	if (strcmp(KEX_DSS, ktype) != 0) {
+		error("dsa_serverkey_from_blob: cannot handle type  %s", ktype);
+		key_free(key);
+		return NULL;
+	}
+	buffer_get_bignum2(&b, dsa->p);
+	buffer_get_bignum2(&b, dsa->q);
+	buffer_get_bignum2(&b, dsa->g);
+	buffer_get_bignum2(&b, dsa->pub_key);
+	rlen = buffer_len(&b);
+	if(rlen != 0)
+		error("dsa_serverkey_from_blob: remaining bytes in serverhostkey %d", rlen);
+	buffer_free(&b);
+
+	debug("keytype %s", ktype);
+#ifdef DEBUG_DSS
+	DSA_print_fp(stderr, dsa, 8);
+#endif
+	return key;
+}
+DSA *
+dsa_load_private(char *filename)
+{
+	DSA *dsa;
+	BIO *in;
+
+	in = BIO_new(BIO_s_file());
+	if (in == NULL)
+		fatal("BIO_new failed");
+	if (BIO_read_filename(in, filename) <= 0)
+		fatal("BIO_read failed %s: %s", filename, strerror(errno));
+	fprintf(stderr, "read DSA private key\n");
+	dsa = PEM_read_bio_DSAPrivateKey(in,NULL,NULL,NULL);
+	if (dsa == NULL)
+		fatal("PEM_read_bio_DSAPrivateKey failed %s", filename);
+	BIO_free(in);
+	return dsa;
+}
+Key *
+dsa_get_serverkey(char *filename)
+{
+	Key *k = key_new(KEY_EMPTY);
+	k->type = KEY_DSA;
+	k->dsa = dsa_load_private(filename);
+#ifdef DEBUG_DSS
+	DSA_print_fp(stderr, dsa, 8);
+#endif
+	return k;
+}
+int
+dsa_make_serverkey_blob(Key *key, unsigned char **blobp, unsigned int *lenp)
+{
+	Buffer b;
+	int len;
+	unsigned char *buf;
+
+	if (key == NULL || key->type != KEY_DSA)
+		return 0;
+	buffer_init(&b);
+	buffer_put_cstring(&b, KEX_DSS);
+	buffer_put_bignum2(&b, key->dsa->p);
+	buffer_put_bignum2(&b, key->dsa->q);
+	buffer_put_bignum2(&b, key->dsa->g);
+	buffer_put_bignum2(&b, key->dsa->pub_key);
+	len = buffer_len(&b);
+	buf = xmalloc(len);
+	memcpy(buf, buffer_ptr(&b), len);
+	memset(buffer_ptr(&b), 0, len);
+	buffer_free(&b);
+	if (lenp != NULL)
+		*lenp = len;
+	if (blobp != NULL)
+		*blobp = buf;
+	return len;
+}
+int
+dsa_sign(
+    Key *key,
+    unsigned char **sigp, int *lenp,
+    unsigned char *hash, int hlen)
+{
+	unsigned char *digest;
+	unsigned char *ret;
+	DSA_SIG *sig;
+	EVP_MD *evp_md = EVP_sha1();
+	EVP_MD_CTX md;
+	unsigned int rlen;
+	unsigned int slen;
+	unsigned int len;
+	unsigned char sigblob[SIGBLOB_LEN];
+	Buffer b;
+
+	if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
+		error("dsa_sign: no DSA key");
+		return -1;
+	}
+	digest = xmalloc(evp_md->md_size);
+	EVP_DigestInit(&md, evp_md);
+	EVP_DigestUpdate(&md, hash, hlen);
+	EVP_DigestFinal(&md, digest, NULL);
+
+	sig = DSA_do_sign(digest, evp_md->md_size, key->dsa);
+
+	rlen = BN_num_bytes(sig->r);
+	slen = BN_num_bytes(sig->s);
+	if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
+		error("bad sig size %d %d", rlen, slen);
+		DSA_SIG_free(sig);
+		return -1;
+	}
+	debug("sig size %d %d", rlen, slen);
+
+	memset(sigblob, 0, SIGBLOB_LEN);
+	BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen);
+	BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen);
+	DSA_SIG_free(sig);
+
+	if (datafellows) {
+		debug("datafellows");
+		ret = xmalloc(SIGBLOB_LEN);
+		memcpy(ret, sigblob, SIGBLOB_LEN);
+		if (lenp != NULL)
+			*lenp = SIGBLOB_LEN;
+		if (sigp != NULL)
+			*sigp = ret;
+	} else {
+		/* ietf-drafts */
+		buffer_init(&b);
+		buffer_put_cstring(&b, KEX_DSS);
+		buffer_put_string(&b, sigblob, SIGBLOB_LEN);
+		len = buffer_len(&b);
+		ret = xmalloc(len);
+		memcpy(ret, buffer_ptr(&b), len);
+		buffer_free(&b);
+		if (lenp != NULL)
+			*lenp = len;
+		if (sigp != NULL)
+			*sigp = ret;
+	}
+	return 0;
+}
+int
+dsa_verify(
+    Key *key,
+    unsigned char *signature, int signaturelen,
+    unsigned char *hash, int hlen)
+{
+	Buffer b;
+	unsigned char *digest;
+	DSA_SIG *sig;
+	EVP_MD *evp_md = EVP_sha1();
+	EVP_MD_CTX md;
+	char *ktype;
+	unsigned char *sigblob;
+	char *txt;
+	unsigned int len;
+	int rlen;
+	int ret;
+
+	if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
+		error("dsa_verify: no DSA key");
+		return -1;
+	}
+
+	if (datafellows && signaturelen != SIGBLOB_LEN) {
+		log("heh? datafellows ssh2 complies with ietf-drafts????");
+		datafellows = 0;
+	}
+
+	debug("len %d datafellows %d", signaturelen, datafellows);
+
+	/* fetch signature */
+	if (datafellows) {
+		sigblob = signature;
+		len = signaturelen;
+	} else {
+		/* ietf-drafts */
+		buffer_init(&b);
+		buffer_append(&b, (char *) signature, signaturelen);
+		ktype = buffer_get_string(&b, NULL);
+		sigblob = (unsigned char *)buffer_get_string(&b, &len);
+		rlen = buffer_len(&b);
+		if(rlen != 0)
+			error("remaining bytes in signature %d", rlen);
+		buffer_free(&b);
+	}
+
+	if (len != SIGBLOB_LEN) {
+		fatal("bad sigbloblen %d != SIGBLOB_LEN", len);
+	}
+
+	/* parse signature */
+	sig = DSA_SIG_new();
+	sig->r = BN_new();
+	sig->s = BN_new();
+	BN_bin2bn(sigblob, INTBLOB_LEN, sig->r);
+	BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s);
+	if (!datafellows) {
+		memset(sigblob, 0, len);
+		xfree(sigblob);
+	}
+	
+	/* sha1 the signed data (== session_id == hash) */
+	digest = xmalloc(evp_md->md_size);
+	EVP_DigestInit(&md, evp_md);
+	EVP_DigestUpdate(&md, hash, hlen);
+	EVP_DigestFinal(&md, digest, NULL);
+
+	ret = DSA_do_verify(digest, evp_md->md_size, sig, key->dsa);
+
+	memset(digest, 0, evp_md->md_size);
+	xfree(digest);
+	DSA_SIG_free(sig);
+
+	switch (ret) {
+	case 1:
+		txt = "correct";
+		break;
+	case 0:
+		txt = "incorrect";
+		break;
+	case -1:
+	default:
+		txt = "error";
+		break;
+	}
+	debug("dsa_verify: signature %s", txt);
+	return ret;
+}