Protocol version 1.2 integrations
[silc.git] / lib / silccore / silcauth.c
index e66f9653834e69de3e69b0099bf82d4ef81a268d..c93f02df1e2b0213a4dce16c2b90a79441cfc373 100644 (file)
@@ -1,16 +1,15 @@
 /*
 
-  silcauth.c
+  silcauth.c 
 
-  Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+  Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 2001 Pekka Riikonen
+  Copyright (C) 2001 - 2002 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
-  the Free Software Foundation; either version 2 of the License, or
-  (at your option) any later version.
-  
+  the Free Software Foundation; version 2 of the License.
+
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@@ -21,6 +20,8 @@
 
 #include "silcincludes.h"
 #include "silcauth.h"
+#include "silcchannel_i.h"
+#include "silcprivate_i.h"
 
 /******************************************************************************
 
 
 /* Authentication Payload structure */
 struct SilcAuthPayloadStruct {
-  uint16 len;
-  uint16 auth_method;
-  uint16 random_len;
+  SilcUInt16 len;
+  SilcUInt16 auth_method;
+  SilcUInt16 random_len;
   unsigned char *random_data;
-  uint16 auth_len;
+  SilcUInt16 auth_len;
   unsigned char *auth_data;
 };
 
 /* Parses and returns Authentication Payload */
 
 SilcAuthPayload silc_auth_payload_parse(const unsigned char *data,
-                                       uint32 data_len)
+                                       SilcUInt32 data_len)
 {
   SilcBufferStruct buffer;
-  SilcAuthPayload new;
+  SilcAuthPayload newp;
   int ret;
 
   SILC_LOG_DEBUG(("Parsing Authentication Payload"));
 
   silc_buffer_set(&buffer, (unsigned char *)data, data_len);
-  new = silc_calloc(1, sizeof(*new));
+  newp = silc_calloc(1, sizeof(*newp));
+  if (!newp)
+    return NULL;
 
   /* Parse the payload */
-  ret = silc_buffer_unformat(&buffer, 
-                            SILC_STR_UI_SHORT(&new->len),
-                            SILC_STR_UI_SHORT(&new->auth_method),
-                            SILC_STR_UI16_NSTRING_ALLOC(&new->random_data,
-                                                        &new->random_len),
-                            SILC_STR_UI16_NSTRING_ALLOC(&new->auth_data,
-                                                        &new->auth_len),
+  ret = silc_buffer_unformat(&buffer,
+                            SILC_STR_UI_SHORT(&newp->len),
+                            SILC_STR_UI_SHORT(&newp->auth_method),
+                            SILC_STR_UI16_NSTRING_ALLOC(&newp->random_data,
+                                                        &newp->random_len),
+                            SILC_STR_UI16_NSTRING_ALLOC(&newp->auth_data,
+                                                        &newp->auth_len),
                             SILC_STR_END);
   if (ret == -1) {
-    silc_free(new);
+    silc_free(newp);
+    return NULL;
+  }
+
+  if (newp->len != buffer.len || 
+      newp->random_len + newp->auth_len > buffer.len - 8) {
+    silc_auth_payload_free(newp);
     return NULL;
   }
 
-  if (new->len != buffer.len) {
-    silc_auth_payload_free(new);
+  /* Authentication data must be provided */
+  if (newp->auth_len < 1)  {
+    silc_auth_payload_free(newp);
     return NULL;
   }
 
   /* If password authentication, random data must not be set */
-  if (new->auth_method == SILC_AUTH_PASSWORD && new->random_len) {
-    silc_auth_payload_free(new);
+  if (newp->auth_method == SILC_AUTH_PASSWORD && newp->random_len) {
+    silc_auth_payload_free(newp);
     return NULL;
   }
 
-  return new;
+  /* If public key authentication, random data must be at least 128 bytes */
+  if (newp->auth_method == SILC_AUTH_PUBLIC_KEY && newp->random_len < 128) {
+    silc_auth_payload_free(newp);
+    return NULL;
+  }
+
+  return newp;
 }
 
 /* Encodes authentication payload into buffer and returns it */
 
 SilcBuffer silc_auth_payload_encode(SilcAuthMethod method,
                                    const unsigned char *random_data,
-                                   uint16 random_len,
+                                   SilcUInt16 random_len,
                                    const unsigned char *auth_data,
-                                   uint16 auth_len)
+                                   SilcUInt16 auth_len)
 {
   SilcBuffer buffer;
-  uint32 len;
+  SilcUInt32 len;
+  unsigned char *autf8 = NULL;
+  SilcUInt32 autf8_len;
 
   SILC_LOG_DEBUG(("Encoding Authentication Payload"));
 
+  /* Passphrase MUST be UTF-8 encoded, encode if it is not */
+  if (method == SILC_AUTH_PASSWORD && !silc_utf8_valid(auth_data, auth_len)) {
+    autf8_len = silc_utf8_encoded_len(auth_data, auth_len, 0);
+    if (!autf8_len)
+      return NULL;
+    autf8 = silc_calloc(autf8_len, sizeof(*autf8));
+    auth_len = silc_utf8_encode(auth_data, auth_len, 0, autf8, autf8_len);
+    auth_data = (const unsigned char *)autf8;
+  }
+
   len = 2 + 2 + 2 + random_len + 2 + auth_len;
-  buffer = silc_buffer_alloc(len);
-  silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
+  buffer = silc_buffer_alloc_size(len);
+  if (!buffer) {
+    silc_free(autf8);
+    return NULL;
+  }
+
   silc_buffer_format(buffer,
                     SILC_STR_UI_SHORT(len),
                     SILC_STR_UI_SHORT(method),
@@ -105,6 +137,7 @@ SilcBuffer silc_auth_payload_encode(SilcAuthMethod method,
                     SILC_STR_UI_XNSTRING(auth_data, auth_len),
                     SILC_STR_END);
 
+  silc_free(autf8);
   return buffer;
 }
 
@@ -132,10 +165,10 @@ SilcAuthMethod silc_auth_get_method(SilcAuthPayload payload)
   return payload->auth_method;
 }
 
-/* Get the authentication data */
+/* Get the authentication data. If this is passphrase it is UTF-8 encoded. */
 
 unsigned char *silc_auth_get_data(SilcAuthPayload payload,
-                                 uint32 *auth_len)
+                                 SilcUInt32 *auth_len)
 {
   if (auth_len)
     *auth_len = payload->auth_len;
@@ -153,14 +186,14 @@ unsigned char *silc_auth_get_data(SilcAuthPayload payload,
    dictates. */
 
 static unsigned char *
-silc_auth_public_key_encode_data(SilcPublicKey public_key, 
-                                const unsigned char *random,
-                                uint32 random_len, const void *id,
-                                SilcIdType type, uint32 *ret_len)
+silc_auth_public_key_encode_data(SilcPublicKey public_key,
+                                const unsigned char *randomdata,
+                                SilcUInt32 random_len, const void *id,
+                                SilcIdType type, SilcUInt32 *ret_len)
 {
   SilcBuffer buf;
   unsigned char *pk, *id_data, *ret;
-  uint32 pk_len, id_len;
+  SilcUInt32 pk_len, id_len;
 
   pk = silc_pkcs_public_key_encode(public_key, &pk_len);
   if (!pk)
@@ -173,20 +206,26 @@ silc_auth_public_key_encode_data(SilcPublicKey public_key,
   }
   id_len = silc_id_get_len(id, type);
 
-  buf = silc_buffer_alloc(random_len + id_len + pk_len);
-  silc_buffer_pull_tail(buf, SILC_BUFFER_END(buf));
+  buf = silc_buffer_alloc_size(random_len + id_len + pk_len);
+  if (!buf) {
+    silc_free(pk);
+    silc_free(id_data);
+    return NULL;
+  }
   silc_buffer_format(buf,
-                    SILC_STR_UI_XNSTRING(random, random_len),
+                    SILC_STR_UI_XNSTRING(randomdata, random_len),
                     SILC_STR_UI_XNSTRING(id_data, id_len),
                     SILC_STR_UI_XNSTRING(pk, pk_len),
                     SILC_STR_END);
-  
-  ret = silc_calloc(buf->len + 1, sizeof(*ret));
-  memcpy(ret, buf->data, buf->len);
+
+  ret = silc_memdup(buf->data, buf->len);
+  if (!ret)
+    return NULL;
 
   if (ret_len)
     *ret_len = buf->len;
 
+  silc_buffer_clear(buf);
   silc_buffer_free(buf);
   silc_free(id_data);
   silc_free(pk);
@@ -200,32 +239,35 @@ silc_auth_public_key_encode_data(SilcPublicKey public_key,
 
 SilcBuffer silc_auth_public_key_auth_generate(SilcPublicKey public_key,
                                              SilcPrivateKey private_key,
-                                             SilcHash hash,
+                                             SilcRng rng, SilcHash hash,
                                              const void *id, SilcIdType type)
 {
-  unsigned char *random;
-  unsigned char auth_data[1024];
-  uint32 auth_len;
+  unsigned char *randomdata;
+  unsigned char auth_data[2048];
+  SilcUInt32 auth_len;
   unsigned char *tmp;
-  uint32 tmp_len;
+  SilcUInt32 tmp_len;
   SilcBuffer buf;
   SilcPKCS pkcs;
 
   SILC_LOG_DEBUG(("Generating Authentication Payload with data"));
 
   /* Get 256 bytes of random data */
-  random = silc_rng_global_get_rn_data(256);
-  if (!random)
+  if (rng)
+    randomdata = silc_rng_get_rn_data(rng, 256);
+  else
+    randomdata = silc_rng_global_get_rn_data(256);
+  if (!randomdata)
     return NULL;
-  
+
   /* Encode the auth data */
-  tmp = silc_auth_public_key_encode_data(public_key, random, 256, id, type
-                                        &tmp_len);
+  tmp = silc_auth_public_key_encode_data(public_key, randomdata, 256, id
+                                        type, &tmp_len);
   if (!tmp)
     return NULL;
 
   /* Allocate PKCS object */
-  if (!silc_pkcs_alloc(public_key->name, &pkcs)) {
+  if (!silc_pkcs_alloc(private_key->name, &pkcs)) {
     memset(tmp, 0, tmp_len);
     silc_free(tmp);
     return NULL;
@@ -234,25 +276,26 @@ SilcBuffer silc_auth_public_key_auth_generate(SilcPublicKey public_key,
   silc_pkcs_private_key_set(pkcs, private_key);
 
   /* Compute the hash and the signature. */
-  if (!silc_pkcs_sign_with_hash(pkcs, hash, tmp, tmp_len, auth_data,
+  if (silc_pkcs_get_key_len(pkcs) / 8 > sizeof(auth_data) - 1 ||
+      !silc_pkcs_sign_with_hash(pkcs, hash, tmp, tmp_len, auth_data,
                                &auth_len)) {
-    memset(random, 0, 256);
+    memset(randomdata, 0, 256);
     memset(tmp, 0, tmp_len);
     silc_free(tmp);
-    silc_free(random);
+    silc_free(randomdata);
     silc_pkcs_free(pkcs);
     return NULL;
   }
 
   /* Encode Authentication Payload */
-  buf = silc_auth_payload_encode(SILC_AUTH_PUBLIC_KEY, random, 256,
+  buf = silc_auth_payload_encode(SILC_AUTH_PUBLIC_KEY, randomdata, 256,
                                 auth_data, auth_len);
 
   memset(tmp, 0, tmp_len);
   memset(auth_data, 0, sizeof(auth_data));
-  memset(random, 0, 256);
+  memset(randomdata, 0, 256);
   silc_free(tmp);
-  silc_free(random);
+  silc_free(randomdata);
   silc_pkcs_free(pkcs);
 
   return buf;
@@ -266,14 +309,14 @@ bool silc_auth_public_key_auth_verify(SilcAuthPayload payload,
                                      const void *id, SilcIdType type)
 {
   unsigned char *tmp;
-  uint32 tmp_len;
+  SilcUInt32 tmp_len;
   SilcPKCS pkcs;
 
   SILC_LOG_DEBUG(("Verifying authentication data"));
 
   /* Encode auth data */
-  tmp = silc_auth_public_key_encode_data(public_key, payload->random_data, 
-                                        payload->random_len, 
+  tmp = silc_auth_public_key_encode_data(public_key, payload->random_data,
+                                        payload->random_len,
                                         id, type, &tmp_len);
   if (!tmp) {
     SILC_LOG_DEBUG(("Authentication failed"));
@@ -311,8 +354,8 @@ bool silc_auth_public_key_auth_verify(SilcAuthPayload payload,
 /* Same as above but the payload is not parsed yet. This will parse it. */
 
 bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
-                                          uint32 payload_len,
-                                          SilcPublicKey public_key, 
+                                          SilcUInt32 payload_len,
+                                          SilcPublicKey public_key,
                                           SilcHash hash,
                                           const void *id, SilcIdType type)
 {
@@ -325,7 +368,7 @@ bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
     return FALSE;
   }
 
-  ret = silc_auth_public_key_auth_verify(auth_payload, public_key, hash, 
+  ret = silc_auth_public_key_auth_verify(auth_payload, public_key, hash,
                                         id, type);
 
   silc_auth_payload_free(auth_payload);
@@ -333,7 +376,7 @@ bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
   return ret;
 }
 
-/* Verifies the authentication data directly from the Authentication 
+/* Verifies the authentication data directly from the Authentication
    Payload. Supports all authentication methods. If the authentication
    method is passphrase based then the `auth_data' and `auth_data_len'
    are the passphrase and its length. If the method is public key
@@ -341,12 +384,12 @@ bool silc_auth_public_key_auth_verify_data(const unsigned char *payload,
    `auth_data_len' is ignored. */
 
 bool silc_auth_verify(SilcAuthPayload payload, SilcAuthMethod auth_method,
-                     const void *auth_data, uint32 auth_data_len, 
+                     const void *auth_data, SilcUInt32 auth_data_len,
                      SilcHash hash, const void *id, SilcIdType type)
 {
   SILC_LOG_DEBUG(("Verifying authentication"));
 
-  if (auth_method != payload->auth_method)
+  if (!payload || auth_method != payload->auth_method)
     return FALSE;
 
   switch (payload->auth_method) {
@@ -358,8 +401,14 @@ bool silc_auth_verify(SilcAuthPayload payload, SilcAuthMethod auth_method,
   case SILC_AUTH_PASSWORD:
     /* Passphrase based authentication. The `pkcs', `hash', `id' and `type'
        arguments are not needed. */
+
+    /* Sanity checks */
+    if ((payload->auth_len == 0) || !auth_data ||
+       payload->auth_len != auth_data_len)
+      break;
+
     if (!memcmp(payload->auth_data, auth_data, auth_data_len)) {
-      SILC_LOG_DEBUG(("Authentication successful"));
+      SILC_LOG_DEBUG(("Passphrase Authentication successful"));
       return TRUE;
     }
     break;
@@ -381,19 +430,20 @@ bool silc_auth_verify(SilcAuthPayload payload, SilcAuthMethod auth_method,
 
 /* Same as above but parses the authentication payload before verify. */
 
-bool silc_auth_verify_data(const unsigned char *payload, uint32 payload_len,
+bool silc_auth_verify_data(const unsigned char *payload,
+                          SilcUInt32 payload_len,
                           SilcAuthMethod auth_method, const void *auth_data,
-                          uint32 auth_data_len, SilcHash hash, 
+                          SilcUInt32 auth_data_len, SilcHash hash,
                           const void *id, SilcIdType type)
 {
   SilcAuthPayload auth_payload;
-  int ret;
+  bool ret;
 
   auth_payload = silc_auth_payload_parse(payload, payload_len);
-  if (!auth_payload)
+  if (!auth_payload || (auth_payload->auth_len == 0))
     return FALSE;
 
-  ret = silc_auth_verify(auth_payload, auth_method, auth_data, auth_data_len, 
+  ret = silc_auth_verify(auth_payload, auth_method, auth_data, auth_data_len,
                         hash, id, type);
 
   silc_auth_payload_free(auth_payload);
@@ -409,52 +459,55 @@ bool silc_auth_verify_data(const unsigned char *payload, uint32 payload_len,
 
 /* The Key Agreement protocol structure */
 struct SilcKeyAgreementPayloadStruct {
-  uint16 hostname_len;
+  SilcUInt16 hostname_len;
   unsigned char *hostname;
-  uint32 port;
+  SilcUInt32 port;
 };
 
 /* Parses and returns an allocated Key Agreement payload. */
 
-SilcKeyAgreementPayload 
+SilcKeyAgreementPayload
 silc_key_agreement_payload_parse(const unsigned char *payload,
-                                uint32 payload_len)
+                                SilcUInt32 payload_len)
 {
   SilcBufferStruct buffer;
-  SilcKeyAgreementPayload new;
+  SilcKeyAgreementPayload newp;
   int ret;
 
   SILC_LOG_DEBUG(("Parsing Key Agreement Payload"));
 
   silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
-  new = silc_calloc(1, sizeof(*new));
+  newp = silc_calloc(1, sizeof(*newp));
+  if (!newp)
+    return NULL;
 
   /* Parse the payload */
-  ret = silc_buffer_unformat(&buffer, 
-                            SILC_STR_UI16_NSTRING_ALLOC(&new->hostname,
-                                                        &new->hostname_len),
-                            SILC_STR_UI_INT(&new->port),
+  ret = silc_buffer_unformat(&buffer,
+                            SILC_STR_UI16_NSTRING_ALLOC(&newp->hostname,
+                                                        &newp->hostname_len),
+                            SILC_STR_UI_INT(&newp->port),
                             SILC_STR_END);
   if (ret == -1) {
-    silc_free(new);
+    silc_free(newp);
     return NULL;
   }
 
-  return new;
+  return newp;
 }
 
 /* Encodes the Key Agreement protocol and returns the encoded buffer */
 
 SilcBuffer silc_key_agreement_payload_encode(const char *hostname,
-                                            uint32 port)
+                                            SilcUInt32 port)
 {
   SilcBuffer buffer;
-  uint32 len = hostname ? strlen(hostname) : 0;
+  SilcUInt32 len = hostname ? strlen(hostname) : 0;
 
   SILC_LOG_DEBUG(("Encoding Key Agreement Payload"));
 
-  buffer = silc_buffer_alloc(2 + len + 4);
-  silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
+  buffer = silc_buffer_alloc_size(2 + len + 4);
+  if (!buffer)
+    return NULL;
   silc_buffer_format(buffer,
                     SILC_STR_UI_SHORT(len),
                     SILC_STR_UI_XNSTRING(hostname, len),
@@ -483,7 +536,323 @@ char *silc_key_agreement_get_hostname(SilcKeyAgreementPayload payload)
 
 /* Returns the port in the payload */
 
-uint32 silc_key_agreement_get_port(SilcKeyAgreementPayload payload)
+SilcUInt32 silc_key_agreement_get_port(SilcKeyAgreementPayload payload)
 {
   return payload->port;
 }
+
+/******************************************************************************
+
+                     SILC_MESSAGE_FLAG_SIGNED Payload
+
+******************************************************************************/
+
+/* The SILC_MESSAGE_FLAG_SIGNED Payload */
+struct SilcSignedPayloadStruct {
+  SilcUInt16 pk_len;
+  SilcUInt16 pk_type;
+  SilcUInt16 sign_len;
+  unsigned char *pk_data;
+  unsigned char *sign_data;
+};
+
+/* Encodes the data to be signed to SILC_MESSAGE_FLAG_SIGNED Payload */
+
+static SilcBuffer
+silc_signed_payload_encode_data(const unsigned char *message_payload,
+                               SilcUInt32 message_payload_len,
+                               unsigned char *pk,
+                               SilcUInt32 pk_len, SilcUInt32 pk_type)
+{
+  SilcBuffer sign;
+
+  sign = silc_buffer_alloc_size(message_payload_len + 4 + pk_len);
+  if (!sign)
+    return NULL;
+
+  silc_buffer_format(sign,
+                    SILC_STR_UI_XNSTRING(message_payload,
+                                         message_payload_len),
+                    SILC_STR_UI_SHORT(pk_len),
+                    SILC_STR_UI_SHORT(pk_type),
+                    SILC_STR_END);
+
+  if (pk && pk_len) {
+    silc_buffer_pull(sign, message_payload_len + 4);
+    silc_buffer_format(sign,
+                      SILC_STR_UI_XNSTRING(pk, pk_len),
+                      SILC_STR_END);
+    silc_buffer_push(sign, message_payload_len + 4);
+  }
+
+  return sign;
+}
+
+/* Parses the SILC_MESSAGE_FLAG_SIGNED Payload */
+
+SilcSignedPayload silc_signed_payload_parse(const unsigned char *data,
+                                           SilcUInt32 data_len)
+{
+  SilcSignedPayload sig;
+  SilcBufferStruct buffer;
+  int ret;
+
+  SILC_LOG_DEBUG(("Parsing SILC_MESSAGE_FLAG_SIGNED Payload"));
+
+  silc_buffer_set(&buffer, (unsigned char *)data, data_len);
+  sig = silc_calloc(1, sizeof(*sig));
+  if (!sig)
+    return NULL;
+
+  /* Parse the payload */
+  ret = silc_buffer_unformat(&buffer,
+                            SILC_STR_UI_SHORT(&sig->pk_len),
+                            SILC_STR_UI_SHORT(&sig->pk_type),
+                            SILC_STR_END);
+  if (ret == -1 || sig->pk_len > data_len - 4) {
+    silc_signed_payload_free(sig);
+    return NULL;
+  }
+
+  silc_buffer_pull(&buffer, 4);
+  ret = silc_buffer_unformat(&buffer,
+                            SILC_STR_UI_XNSTRING_ALLOC(&sig->pk_data,
+                                                       sig->pk_len),
+                            SILC_STR_UI16_NSTRING_ALLOC(&sig->sign_data,
+                                                        &sig->sign_len),
+                            SILC_STR_END);
+  if (ret == -1) {
+    silc_signed_payload_free(sig);
+    return NULL;
+  }
+  silc_buffer_push(&buffer, 4);
+
+  /* Signature must be provided */
+  if (sig->sign_len < 1)  {
+    silc_signed_payload_free(sig);
+    return NULL;
+  }
+
+  return sig;
+}
+
+/* Encodes the SILC_MESSAGE_FLAG_SIGNED Payload and computes the digital
+   signature. */
+
+SilcBuffer silc_signed_payload_encode(const unsigned char *message_payload,
+                                     SilcUInt32 message_payload_len,
+                                     SilcPublicKey public_key,
+                                     SilcPrivateKey private_key,
+                                     SilcHash hash,
+                                     bool include_public_key)
+{
+  SilcBuffer buffer, sign;
+  SilcPKCS pkcs;
+  unsigned char auth_data[2048];
+  SilcUInt32 auth_len;
+  unsigned char *pk = NULL;
+  SilcUInt32 pk_len = 0;
+  SilcUInt16 pk_type;
+
+  if (!message_payload || !message_payload_len || !private_key || !hash)
+    return NULL;
+  if (include_public_key && !public_key)
+    return NULL;
+
+  if (include_public_key)
+    pk = silc_pkcs_public_key_encode(public_key, &pk_len);
+
+  /* Now we support only SILC style public key */
+  pk_type = SILC_SKE_PK_TYPE_SILC;
+
+  /* Encode the data to be signed */
+  sign = silc_signed_payload_encode_data(message_payload,
+                                        message_payload_len,
+                                        pk, pk_len, pk_type);
+  if (!sign) {
+    silc_free(pk);
+    return NULL;
+  }
+
+  /* Sign the buffer */
+
+  /* Allocate PKCS object */
+  if (!silc_pkcs_alloc(private_key->name, &pkcs)) {
+    silc_buffer_clear(sign);
+    silc_buffer_free(sign);
+    silc_free(pk);
+    return NULL;
+  }
+  silc_pkcs_private_key_set(pkcs, private_key);
+
+  /* Compute the hash and the signature. */
+  if (silc_pkcs_get_key_len(pkcs) / 8 > sizeof(auth_data) - 1 ||
+      !silc_pkcs_sign_with_hash(pkcs, hash, sign->data, sign->len, auth_data,
+                               &auth_len)) {
+    silc_buffer_clear(sign);
+    silc_buffer_free(sign);
+    silc_pkcs_free(pkcs);
+    silc_free(pk);
+    return NULL;
+  }
+
+  /* Encode the SILC_MESSAGE_FLAG_SIGNED Payload */
+
+  buffer = silc_buffer_alloc_size(4 + pk_len + 2 + auth_len);
+  if (!buffer) {
+    silc_buffer_clear(sign);
+    silc_buffer_free(sign);
+    silc_pkcs_free(pkcs);
+    memset(auth_data, 0, sizeof(auth_data));
+    silc_free(pk);
+    return NULL;
+  }
+
+  silc_buffer_format(sign,
+                    SILC_STR_UI_SHORT(pk_len),
+                    SILC_STR_UI_SHORT(pk_type),
+                    SILC_STR_END);
+
+  if (pk_len && pk) {
+    silc_buffer_pull(sign, 4);
+    silc_buffer_format(sign,
+                      SILC_STR_UI_XNSTRING(pk, pk_len),
+                      SILC_STR_END);
+    silc_buffer_push(sign, 4);
+  }
+
+  silc_buffer_pull(sign, 4 + pk_len);
+  silc_buffer_format(sign,
+                    SILC_STR_UI_SHORT(auth_len),
+                    SILC_STR_UI_XNSTRING(auth_data, auth_len),
+                    SILC_STR_END);
+  silc_buffer_push(sign, 4 + pk_len);
+
+  memset(auth_data, 0, sizeof(auth_data));
+  silc_pkcs_free(pkcs);
+  silc_buffer_clear(sign);
+  silc_buffer_free(sign);
+  silc_free(pk);
+
+  return buffer;
+}
+
+/* Free the payload */
+
+void silc_signed_payload_free(SilcSignedPayload sig)
+{
+  if (sig) {
+    memset(sig->sign_data, 0, sig->sign_len);
+    silc_free(sig->sign_data);
+    silc_free(sig->pk_data);
+    silc_free(sig);
+  }
+}
+
+/* Verify the signature in SILC_MESSAGE_FLAG_SIGNED Payload */
+
+int silc_signed_payload_verify(SilcSignedPayload sig,
+                              bool channel_message,
+                              void *message_payload,
+                              SilcPublicKey remote_public_key,
+                              SilcHash hash)
+{
+  int ret = SILC_AUTH_FAILED;
+#if 0
+  SilcBuffer sign;
+  SilcPKCS pkcs;
+  
+  if (!sig || !remote_public_key || !hash)
+    return ret;
+
+  /* Generate the signature verification data */
+  if (channel_message) {
+    SilcChannelMessagePayload chm =
+      (SilcChannelMessagePayload)message_payload;
+    SilcBuffer tmp;
+
+    /* Encode Channel Message Payload */
+    tmp = silc_buffer_alloc_size(6 + chm->data_len + chm->pad_len +
+                                chm->iv_len);
+    silc_buffer_format(tmp,
+                      SILC_STR_UI_SHORT(chm->flags),
+                      SILC_STR_UI_SHORT(chm->data_len),
+                      SILC_STR_UI_XNSTRING(chm->data, chm->data_len),
+                      SILC_STR_UI_SHORT(chm->pad_len),
+                      SILC_STR_UI_XNSTRING(chm->pad, chm->pad_len),
+                      SILC_STR_UI_XNSTRING(chm->iv, chm->iv_len),
+                      SILC_STR_END);
+
+    sign = silc_signed_payload_encode_data(tmp->data, tmp->len,
+                                          sig->pk_data, sig->pk_len,
+                                          sig->pk_type);
+    silc_buffer_clear(tmp);
+    silc_buffer_free(tmp);
+  } else {
+    SilcPrivateMessagePayload prm =
+      (SilcPrivateMessagePayload)message_payload;
+    SilcBuffer tmp;
+
+    /* Encode Private Message Payload */
+    tmp = silc_buffer_alloc_size(4 + prm->data_len +
+                                SILC_PRIVATE_MESSAGE_PAD(4 + prm->data_len));
+    silc_buffer_format(tmp,
+                      SILC_STR_UI_SHORT(prm->flags),
+                      SILC_STR_UI_SHORT(prm->message_len),
+                      SILC_STR_UI_XNSTRING(prm->message, prm->message_len),
+                      SILC_STR_END);
+
+    sign = silc_signed_payload_encode_data(tmp->data, tmp->len,
+                                          sig->pk_data, sig->pk_len,
+                                          sig->pk_type);
+    silc_buffer_clear(tmp);
+    silc_buffer_free(tmp);
+  }
+
+  if (!sign)
+    return ret;
+  
+  /* Allocate PKCS object */
+  if (!silc_pkcs_alloc(remote_public_key->name, &pkcs)) {
+    silc_buffer_clear(sign);
+    silc_buffer_free(sign);
+    return ret;
+  }
+  silc_pkcs_public_key_set(pkcs, remote_public_key);
+
+  /* Verify the authentication data */
+  if (!silc_pkcs_verify_with_hash(pkcs, hash, payload->sign_data
+                                 payload->sign_len,
+                                 sign->data, sign->len)) {
+
+    silc_buffer_clear(sign);
+    silc_buffer_free(sign);
+    silc_pkcs_free(pkcs);
+    SILC_LOG_DEBUG(("Signature verification failed"));
+    return ret;
+  }
+
+  ret = SILC_AUTH_OK;
+
+  silc_buffer_clear(sign);
+  silc_buffer_free(sign);
+  silc_pkcs_free(pkcs);
+
+  SILC_LOG_DEBUG(("Signature verification successful"));
+
+#endif
+  return ret;
+}
+
+/* Return the public key from the payload */
+
+SilcPublicKey silc_signed_payload_get_public_key(SilcSignedPayload sig)
+{
+  SilcPublicKey pk;
+
+  if (!sig->pk_data || !silc_pkcs_public_key_decode(sig->pk_data,
+                                                   sig->pk_len, &pk))
+    return NULL;
+
+  return pk;
+}