1 files changed, 344 insertions, 0 deletions
diff --git a/srtp/crypto/gcrypt/gcryptSrtpSymCrypto.cpp b/srtp/crypto/gcrypt/gcryptSrtpSymCrypto.cpp
new file mode 100644
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--- /dev/null
+++ b/srtp/crypto/gcrypt/gcryptSrtpSymCrypto.cpp
@@ -0,0 +1,344 @@
+/*
+  Copyright (C) 2005, 2004, 2012 Erik Eliasson, Johan Bilien, Werner Dittmann
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library 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 GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+*/
+
+/**
+ * @author Erik Eliasson <eliasson@it.kth.se>
+ * @author Johan Bilien <jobi@via.ecp.fr>
+ * @author Werner Dittmann <Werner.Dittmann@t-online.de>
+ */
+
+extern void initializeGcrypt();
+
+#define MAKE_F8_TEST
+
+#include <gcrypt.h>            // the include of gcrypt
+#include <stdlib.h>
+#include <crypto/SrtpSymCrypto.h>
+#include <crypto/twofish.h>
+
+#include <stdio.h>
+
+SrtpSymCrypto::SrtpSymCrypto(int algo) : key(NULL), algorithm(algo) {
+    initializeGcrypt();
+}
+
+SrtpSymCrypto::SrtpSymCrypto( uint8_t* k, int32_t keyLength, int algo) :
+    key(NULL),  algorithm(algo) {
+
+    initializeGcrypt();
+    setNewKey(k, keyLength);
+}
+
+SrtpSymCrypto::~SrtpSymCrypto() {
+    if (key) {
+        if (algorithm == SrtpEncryptionAESCM || algorithm == SrtpEncryptionAESF8)
+            gcry_cipher_close(static_cast<gcry_cipher_hd_t>(key));
+        else if (algorithm == SrtpEncryptionTWOCM || algorithm == SrtpEncryptionTWOF8) {
+            memset(key, 0, sizeof(Twofish_key));
+            delete[] (uint8_t*)key;
+        }
+        key = NULL;
+    }
+}
+
+static int twoFishInit = 0;
+
+bool SrtpSymCrypto::setNewKey(const uint8_t* k, int32_t keyLength) {
+
+    // release an existing key before setting a new one
+    if (algorithm == SrtpEncryptionAESCM || algorithm == SrtpEncryptionAESF8) {
+        if (key != NULL) {
+            gcry_cipher_close(static_cast<gcry_cipher_hd_t>(key));
+            key = NULL;
+        }
+
+        int algo = 0;
+        if (keyLength == 16) {
+            algo = GCRY_CIPHER_AES;
+        }
+        else if (keyLength == 32) {
+            algo = GCRY_CIPHER_AES256;
+        }
+        else {
+            return false;
+        }
+        gcry_cipher_hd_t tmp;
+        gcry_cipher_open(&tmp, algo, GCRY_CIPHER_MODE_ECB, 0);
+        key = tmp;
+        gcry_cipher_setkey(static_cast<gcry_cipher_hd_t>(key), k, keyLength);
+    }
+    else if (algorithm == SrtpEncryptionTWOCM || algorithm == SrtpEncryptionTWOF8) {
+        if (!twoFishInit) {
+            Twofish_initialise();
+            twoFishInit = 1;
+        }
+        if (key != NULL)
+            delete[] (uint8_t*)key;
+
+        key = new uint8_t[sizeof(Twofish_key)];
+        memset(key, 0, sizeof(Twofish_key));
+        Twofish_prepare_key((Twofish_Byte*)k, keyLength,  (Twofish_key*)key);
+    }
+    else
+        return false;
+
+    return true;
+}
+
+
+void SrtpSymCrypto::encrypt(const uint8_t* input, uint8_t* output) {
+    if (key != NULL) {
+        if (algorithm == SrtpEncryptionAESCM || algorithm == SrtpEncryptionAESF8)
+            gcry_cipher_encrypt (static_cast<gcry_cipher_hd_t>(key),
+                                 output, SRTP_BLOCK_SIZE, input, SRTP_BLOCK_SIZE);
+        else if (algorithm == SrtpEncryptionTWOCM || algorithm == SrtpEncryptionTWOF8)
+            Twofish_encrypt((Twofish_key*)key, (Twofish_Byte*)input,
+                            (Twofish_Byte*)output);
+        }
+}
+
+void SrtpSymCrypto::get_ctr_cipher_stream( uint8_t* output, uint32_t length,
+                                     uint8_t* iv ) {
+    uint16_t ctr = 0;
+
+    unsigned char temp[SRTP_BLOCK_SIZE];
+
+    for(ctr = 0; ctr < length/SRTP_BLOCK_SIZE; ctr++ ){
+        //compute the cipher stream
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, &output[ctr*SRTP_BLOCK_SIZE]);
+    }
+    if ((length % SRTP_BLOCK_SIZE) > 0) {
+        // Treat the last bytes:
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, temp);
+        memcpy(&output[ctr*SRTP_BLOCK_SIZE], temp, length % SRTP_BLOCK_SIZE);
+    }
+}
+
+void SrtpSymCrypto::ctr_encrypt( const uint8_t* input, uint32_t input_length,
+			   uint8_t* output, uint8_t* iv ) {
+
+    if (key == NULL)
+        return;
+
+    uint16_t ctr = 0;
+    unsigned char temp[SRTP_BLOCK_SIZE];
+
+    int l = input_length/SRTP_BLOCK_SIZE;
+    for ( ctr = 0; ctr < l; ctr++ ) {
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, temp);
+        for (int i = 0; i < SRTP_BLOCK_SIZE; i++ ) {
+            *output++ = temp[i] ^ *input++;
+        }
+
+    }
+    l = input_length % SRTP_BLOCK_SIZE;
+    if (l > 0) {
+        // Treat the last bytes:
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, temp);
+        for (int i = 0; i < l; i++ ) {
+            *output++ = temp[i] ^ *input++;
+        }
+    }
+}
+
+void SrtpSymCrypto::ctr_encrypt( uint8_t* data, uint32_t data_length, uint8_t* iv ) {
+
+    if (key == NULL)
+        return;
+    
+    uint16_t ctr = 0;
+    unsigned char temp[SRTP_BLOCK_SIZE];
+
+    int l = data_length/SRTP_BLOCK_SIZE;
+    for (ctr = 0; ctr < l; ctr++ ) {
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, temp);
+        for (int i = 0; i < SRTP_BLOCK_SIZE; i++ ) {
+            *data++ ^= temp[i];
+        }
+
+    }
+    l = data_length % SRTP_BLOCK_SIZE;
+    if (l > 0) {
+        // Treat the last bytes:
+        iv[14] = (uint8_t)((ctr & 0xFF00) >>  8);
+        iv[15] = (uint8_t)((ctr & 0x00FF));
+
+        encrypt(iv, temp);
+        for (int i = 0; i < l; i++ ) {
+            *data++ ^= temp[i];
+        }
+    }
+
+}
+
+void SrtpSymCrypto::f8_encrypt(const uint8_t* data, uint32_t data_length, uint8_t* iv, SrtpSymCrypto* f8Cipher ) {
+
+    f8_encrypt(data, data_length, const_cast<uint8_t*>(data), iv, f8Cipher);
+}
+
+#define MAX_KEYLEN 32
+
+void SrtpSymCrypto::f8_deriveForIV(SrtpSymCrypto* f8Cipher, uint8_t* key, int32_t keyLen,
+             uint8_t* salt, int32_t saltLen) {
+
+    unsigned char *cp_in, *cp_in1, *cp_out;
+
+    unsigned char maskedKey[MAX_KEYLEN];
+    unsigned char saltMask[MAX_KEYLEN];
+
+    if (keyLen > MAX_KEYLEN)
+        return;
+
+    if (saltLen > keyLen)
+        return;
+    /*
+     * First copy the salt into the mask field, then fill with 0x55 to
+     * get a full key.
+     */
+    memcpy(saltMask, salt, saltLen);
+    memset(saltMask+saltLen, 0x55, keyLen-saltLen);
+
+    /*
+     * XOR the original key with the above created mask to
+     * get the special key.
+     */
+    cp_out = maskedKey;
+    cp_in = key;
+    cp_in1 = saltMask;
+    for (int i = 0; i < keyLen; i++) {
+        *cp_out++ = *cp_in++ ^ *cp_in1++;
+    }
+    /*
+     * Prepare the a new AES cipher with the special key to compute IV'
+     */
+    f8Cipher->setNewKey(maskedKey, keyLen);
+}
+
+void SrtpSymCrypto::f8_encrypt(const uint8_t* in, uint32_t in_length, uint8_t* out,
+                         uint8_t* iv, SrtpSymCrypto* f8Cipher ) {
+
+    int offset = 0;
+
+    unsigned char ivAccent[SRTP_BLOCK_SIZE];
+    unsigned char S[SRTP_BLOCK_SIZE];
+
+    F8_CIPHER_CTX f8ctx;
+
+    if (key == NULL)
+        return;
+
+    /*
+     * Get memory for the derived IV (IV')
+     */
+    f8ctx.ivAccent = ivAccent;
+    /*
+     * Use the derived IV encryption setup to encrypt the original IV to produce IV'.
+     */
+    f8Cipher->encrypt(iv, f8ctx.ivAccent);
+
+    f8ctx.J = 0;                        // initialize the counter
+    f8ctx.S = S;                        // get the key stream buffer
+
+    memset(f8ctx.S, 0, SRTP_BLOCK_SIZE); // initial value for key stream
+
+    while (in_length >= SRTP_BLOCK_SIZE) {
+        processBlock(&f8ctx, in+offset, SRTP_BLOCK_SIZE, out+offset);
+        in_length -= SRTP_BLOCK_SIZE;
+        offset += SRTP_BLOCK_SIZE;
+    }
+    if (in_length > 0) {
+        processBlock(&f8ctx, in+offset, in_length, out+offset);
+    }
+}
+
+int SrtpSymCrypto::processBlock(F8_CIPHER_CTX *f8ctx, const uint8_t* in, int32_t length, uint8_t* out) {
+
+    int i;
+    const uint8_t *cp_in;
+    uint8_t* cp_in1, *cp_out;
+    uint32_t *ui32p;
+
+    /*
+     * XOR the previous key stream with IV'
+     * ( S(-1) xor IV' )
+     */
+    cp_in = f8ctx->ivAccent;
+    cp_out = f8ctx->S;
+    for (i = 0; i < SRTP_BLOCK_SIZE; i++) {
+        *cp_out++ ^= *cp_in++;
+    }
+    /*
+     * Now XOR (S(n-1) xor IV') with the current counter, then increment the counter
+     */
+    ui32p = (uint32_t *)f8ctx->S;
+    ui32p[3] ^= htonl(f8ctx->J);
+    f8ctx->J++;
+    /*
+     * Now compute the new key stream using encrypt
+     */
+    encrypt(f8ctx->S, f8ctx->S);
+    /*
+     * as the last step XOR the plain text with the key stream to produce
+     * the ciphertext.
+     */
+    cp_out = out;
+    cp_in = in;
+    cp_in1 = f8ctx->S;
+    for (i = 0; i < length; i++) {
+        *cp_out++ = *cp_in++ ^ *cp_in1++;
+    }
+    return length;
+}
+
+/** EMACS **
+ * Local variables:
+ * mode: c++
+ * c-default-style: ellemtel
+ * c-basic-offset: 4
+ * End:
+ */
+
+