add adler32 checksum algorithm

src/headers/tomcrypt_custom.h

@@ -430,6 +430,8 @@
 #define LTC_HKDF
 #endif /* LTC_NO_HKDF */
 
+#define LTC_ADLER32
+
 #endif /* LTC_NO_MISC */
 
 /* cleanup */

src/headers/tomcrypt_misc.h

@@ -69,6 +69,17 @@ void init_GMP(void);
 #endif
 */
 
+#ifdef LTC_ADLER32
+typedef struct adler32_state_s
+{
+   unsigned short s[2];
+} adler32_state;
+
+void adler32_init(adler32_state *ctx);
+void adler32_update(adler32_state *ctx, const unsigned char *input, unsigned long length);
+void adler32_finish(adler32_state *ctx, void *hash, unsigned long size);
+int adler32_test(void);
+#endif
 
 /* $Source$ */
 /* $Revision$ */

src/misc/adler32.c

@@ -0,0 +1,135 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+#include "tomcrypt.h"
+
+/**
+   @file adler32.c
+   Adler-32 checksum algorithm
+   Written and placed in the public domain by Wei Dai
+   Adapted for libtomcrypt by Steffen Jaeckel
+*/
+#ifdef LTC_ADLER32
+
+static const unsigned long _adler32_base = 65521;
+
+void adler32_init(adler32_state *ctx)
+{
+   LTC_ARGCHKVD(ctx != NULL);
+   ctx->s[0] = 1;
+   ctx->s[1] = 0;
+}
+
+void adler32_update(adler32_state *ctx, const unsigned char *input, unsigned long length)
+{
+   LTC_ARGCHKVD(ctx != NULL);
+   LTC_ARGCHKVD(input != NULL);
+   unsigned long s1 = ctx->s[0];
+   unsigned long s2 = ctx->s[1];
+
+   if (length % 8 != 0) {
+      do {
+         s1 += *input++;
+         s2 += s1;
+         length--;
+      } while (length % 8 != 0);
+
+      if (s1 >= _adler32_base)
+         s1 -= _adler32_base;
+      s2 %= _adler32_base;
+   }
+
+   while (length > 0) {
+      s1 += input[0];
+      s2 += s1;
+      s1 += input[1];
+      s2 += s1;
+      s1 += input[2];
+      s2 += s1;
+      s1 += input[3];
+      s2 += s1;
+      s1 += input[4];
+      s2 += s1;
+      s1 += input[5];
+      s2 += s1;
+      s1 += input[6];
+      s2 += s1;
+      s1 += input[7];
+      s2 += s1;
+
+      length -= 8;
+      input += 8;
+
+      if (s1 >= _adler32_base)
+         s1 -= _adler32_base;
+      s2 %= _adler32_base;
+   }
+
+   LTC_ARGCHKVD(s1 < _adler32_base);
+   LTC_ARGCHKVD(s2 < _adler32_base);
+
+   ctx->s[0] = (unsigned short)s1;
+   ctx->s[1] = (unsigned short)s2;
+}
+
+void adler32_finish(adler32_state *ctx, void *hash, unsigned long size)
+{
+   LTC_ARGCHKVD(ctx != NULL);
+   LTC_ARGCHKVD(hash != NULL);
+
+   unsigned char* h = hash;
+
+   switch (size) {
+      default:
+         h[3] = ctx->s[0] & 0x0ff;
+         /* no break */
+      case 3:
+         h[2] = (ctx->s[0] >> 8) & 0x0ff;
+         /* no break */
+      case 2:
+         h[1] = ctx->s[1] & 0x0ff;
+         /* no break */
+      case 1:
+         h[0] = (ctx->s[1] >> 8) & 0x0ff;
+         /* no break */
+      case 0:
+         ;
+   }
+}
+
+int adler32_test(void)
+{
+#ifndef LTC_TEST
+   return CRYPT_NOP;
+#else
+   const void* in = "libtomcrypt";
+   const unsigned char adler32[] = { 0x1b, 0xe8, 0x04, 0xba };
+   unsigned char out[4];
+   adler32_state ctx;
+   adler32_init(&ctx);
+   adler32_update(&ctx, in, strlen(in));
+   adler32_finish(&ctx, &out, 4);
+   if (XMEMCMP(adler32, out, 4)) {
+#ifdef LTC_TEST_DBG
+      ulong32 _out, _adler32;
+      LOAD32H(_out, out);
+      LOAD32H(_adler32, adler32);
+      printf("adler32 fail! Is: 0x%x Should: 0x%x\n", _out, _adler32);
+#endif
+      return CRYPT_FAIL_TESTVECTOR;
+   }
+   return CRYPT_OK;
+#endif
+}
+#endif
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */

src/misc/crypt/crypt.c

@@ -322,6 +322,9 @@ const char *crypt_build_settings =
 #endif
 
     "\nVarious others: "
+#if defined(LTC_ADLER32)
+    " ADLER32 "
+#endif
 #if defined(LTC_BASE64)
     " BASE64 "
 #endif

src/misc/crypt/crypt_sizes.c

@@ -231,6 +231,10 @@ static const crypt_size _crypt_sizes[] = {
 #endif
     // sprng has no state as it uses other potentially available sources
     // like /dev/random.  See Developers Guide for more info.
+
+#ifdef LTC_ADLER32
+    _SZ_STRINGIFY_T(adler32_state),
+#endif
 };
 
 /* crypt_get_size()

testprof/misc_test.c

@@ -10,6 +10,9 @@ int misc_test(void)
 #endif
 #ifdef LTC_BASE64
    DO(base64_test());
+#endif
+#ifdef LTC_ADLER32
+   DO(adler32_test());
 #endif
    return 0;
 }