* merged with mainline

4 files changed, 503 insertions, 1 deletions

diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
index b17b94319..9b22a90d3 100644
--- a/apt-pkg/contrib/hashes.cc
+++ b/apt-pkg/contrib/hashes.cc
@@ -36,6 +36,7 @@ bool Hashes::AddFD(int Fd,unsigned long Size)
       Size -= Res;
       MD5.Add(Buf,Res);
       SHA1.Add(Buf,Res);
+      SHA256.Add(Buf,Res);
    }
    return true;
 }
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
index 40bbe00a0..eefa7bf41 100644
--- a/apt-pkg/contrib/hashes.h
+++ b/apt-pkg/contrib/hashes.h
@@ -19,6 +19,7 @@
 
 #include <apt-pkg/md5.h>
 #include <apt-pkg/sha1.h>
+#include <apt-pkg/sha256.h>
 
 #include <algorithm>
 
@@ -30,10 +31,11 @@ class Hashes
 
    MD5Summation MD5;
    SHA1Summation SHA1;
+   SHA256Summation SHA256;
    
    inline bool Add(const unsigned char *Data,unsigned long Size)
    {
-      return MD5.Add(Data,Size) && SHA1.Add(Data,Size);
+      return MD5.Add(Data,Size) && SHA1.Add(Data,Size) && SHA256.Add(Data,Size);
    };
    inline bool Add(const char *Data) {return Add((unsigned char *)Data,strlen(Data));};
    bool AddFD(int Fd,unsigned long Size);
diff --git a/apt-pkg/contrib/sha256.cc b/apt-pkg/contrib/sha256.cc
new file mode 100644
index 000000000..b75ce8a84
--- /dev/null
+++ b/apt-pkg/contrib/sha256.cc
@@ -0,0 +1,424 @@
+/*
+ * Cryptographic API.
+ *
+ * SHA-256, as specified in
+ * http://csrc.nist.gov/cryptval/shs/sha256-384-512.pdf
+ *
+ * SHA-256 code by Jean-Luc Cooke <jlcooke@certainkey.com>.
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *
+ * Ported from the Linux kernel to Apt by Anthony Towns <ajt@debian.org>
+ *
+ * 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.
+ *
+ */
+#define SHA256_DIGEST_SIZE      32
+#define SHA256_HMAC_BLOCK_SIZE  64
+
+#define ror32(value,bits) (((value) >> (bits)) | ((value) << (32 - (bits))))
+
+#include <apt-pkg/sha256.h>
+#include <apt-pkg/strutl.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <arpa/inet.h>
+
+typedef uint32_t u32;
+typedef uint8_t  u8;
+
+static inline u32 Ch(u32 x, u32 y, u32 z)
+{
+        return z ^ (x & (y ^ z));
+}
+
+static inline u32 Maj(u32 x, u32 y, u32 z)
+{
+        return (x & y) | (z & (x | y));
+}
+
+#define e0(x)       (ror32(x, 2) ^ ror32(x,13) ^ ror32(x,22))
+#define e1(x)       (ror32(x, 6) ^ ror32(x,11) ^ ror32(x,25))
+#define s0(x)       (ror32(x, 7) ^ ror32(x,18) ^ (x >> 3))
+#define s1(x)       (ror32(x,17) ^ ror32(x,19) ^ (x >> 10))
+
+#define H0         0x6a09e667
+#define H1         0xbb67ae85
+#define H2         0x3c6ef372
+#define H3         0xa54ff53a
+#define H4         0x510e527f
+#define H5         0x9b05688c
+#define H6         0x1f83d9ab
+#define H7         0x5be0cd19
+
+static inline void LOAD_OP(int I, u32 *W, const u8 *input)
+{
+	W[I] = (  ((u32) input[I * 4 + 0] << 24)
+		| ((u32) input[I * 4 + 1] << 16)
+		| ((u32) input[I * 4 + 2] << 8)
+		| ((u32) input[I * 4 + 3]));
+}
+
+static inline void BLEND_OP(int I, u32 *W)
+{
+        W[I] = s1(W[I-2]) + W[I-7] + s0(W[I-15]) + W[I-16];
+}
+
+static void sha256_transform(u32 *state, const u8 *input)
+{
+        u32 a, b, c, d, e, f, g, h, t1, t2;
+        u32 W[64];
+        int i;
+
+        /* load the input */
+        for (i = 0; i < 16; i++)
+                LOAD_OP(i, W, input);
+
+        /* now blend */
+        for (i = 16; i < 64; i++)
+                BLEND_OP(i, W);
+    
+        /* load the state into our registers */
+        a=state[0];  b=state[1];  c=state[2];  d=state[3];
+        e=state[4];  f=state[5];  g=state[6];  h=state[7];
+
+        /* now iterate */
+        t1 = h + e1(e) + Ch(e,f,g) + 0x428a2f98 + W[ 0];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0x71374491 + W[ 1];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0xb5c0fbcf + W[ 2];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0xe9b5dba5 + W[ 3];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x3956c25b + W[ 4];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0x59f111f1 + W[ 5];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x923f82a4 + W[ 6];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0xab1c5ed5 + W[ 7];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0xd807aa98 + W[ 8];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0x12835b01 + W[ 9];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0x243185be + W[10];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0x550c7dc3 + W[11];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x72be5d74 + W[12];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0x80deb1fe + W[13];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x9bdc06a7 + W[14];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0xc19bf174 + W[15];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0xe49b69c1 + W[16];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0xefbe4786 + W[17];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0x0fc19dc6 + W[18];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0x240ca1cc + W[19];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x2de92c6f + W[20];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0x4a7484aa + W[21];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x5cb0a9dc + W[22];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0x76f988da + W[23];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0x983e5152 + W[24];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0xa831c66d + W[25];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0xb00327c8 + W[26];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0xbf597fc7 + W[27];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0xc6e00bf3 + W[28];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0xd5a79147 + W[29];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x06ca6351 + W[30];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0x14292967 + W[31];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0x27b70a85 + W[32];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0x2e1b2138 + W[33];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0x4d2c6dfc + W[34];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0x53380d13 + W[35];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x650a7354 + W[36];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0x766a0abb + W[37];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x81c2c92e + W[38];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0x92722c85 + W[39];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0xa2bfe8a1 + W[40];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0xa81a664b + W[41];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0xc24b8b70 + W[42];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0xc76c51a3 + W[43];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0xd192e819 + W[44];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0xd6990624 + W[45];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0xf40e3585 + W[46];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0x106aa070 + W[47];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0x19a4c116 + W[48];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0x1e376c08 + W[49];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0x2748774c + W[50];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0x34b0bcb5 + W[51];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x391c0cb3 + W[52];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0x4ed8aa4a + W[53];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0x5b9cca4f + W[54];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0x682e6ff3 + W[55];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        t1 = h + e1(e) + Ch(e,f,g) + 0x748f82ee + W[56];
+        t2 = e0(a) + Maj(a,b,c);    d+=t1;    h=t1+t2;
+        t1 = g + e1(d) + Ch(d,e,f) + 0x78a5636f + W[57];
+        t2 = e0(h) + Maj(h,a,b);    c+=t1;    g=t1+t2;
+        t1 = f + e1(c) + Ch(c,d,e) + 0x84c87814 + W[58];
+        t2 = e0(g) + Maj(g,h,a);    b+=t1;    f=t1+t2;
+        t1 = e + e1(b) + Ch(b,c,d) + 0x8cc70208 + W[59];
+        t2 = e0(f) + Maj(f,g,h);    a+=t1;    e=t1+t2;
+        t1 = d + e1(a) + Ch(a,b,c) + 0x90befffa + W[60];
+        t2 = e0(e) + Maj(e,f,g);    h+=t1;    d=t1+t2;
+        t1 = c + e1(h) + Ch(h,a,b) + 0xa4506ceb + W[61];
+        t2 = e0(d) + Maj(d,e,f);    g+=t1;    c=t1+t2;
+        t1 = b + e1(g) + Ch(g,h,a) + 0xbef9a3f7 + W[62];
+        t2 = e0(c) + Maj(c,d,e);    f+=t1;    b=t1+t2;
+        t1 = a + e1(f) + Ch(f,g,h) + 0xc67178f2 + W[63];
+        t2 = e0(b) + Maj(b,c,d);    e+=t1;    a=t1+t2;
+
+        state[0] += a; state[1] += b; state[2] += c; state[3] += d;
+        state[4] += e; state[5] += f; state[6] += g; state[7] += h;
+
+        /* clear any sensitive info... */
+        a = b = c = d = e = f = g = h = t1 = t2 = 0;
+        memset(W, 0, 64 * sizeof(u32));
+}
+
+SHA256Summation::SHA256Summation()
+{
+        Sum.state[0] = H0;
+        Sum.state[1] = H1;
+        Sum.state[2] = H2;
+        Sum.state[3] = H3;
+        Sum.state[4] = H4;
+        Sum.state[5] = H5;
+        Sum.state[6] = H6;
+        Sum.state[7] = H7;
+        Sum.count[0] = Sum.count[1] = 0;
+        memset(Sum.buf, 0, sizeof(Sum.buf));
+        Done = false;
+}
+
+bool SHA256Summation::Add(const u8 *data, unsigned long len)
+{
+        struct sha256_ctx *sctx = &Sum;
+        unsigned int i, index, part_len;
+
+        if (Done) return false;
+
+        /* Compute number of bytes mod 128 */
+        index = (unsigned int)((sctx->count[0] >> 3) & 0x3f);
+
+        /* Update number of bits */
+        if ((sctx->count[0] += (len << 3)) < (len << 3)) {
+                sctx->count[1]++;
+                sctx->count[1] += (len >> 29);
+        }
+
+        part_len = 64 - index;
+
+        /* Transform as many times as possible. */
+        if (len >= part_len) {
+                memcpy(&sctx->buf[index], data, part_len);
+                sha256_transform(sctx->state, sctx->buf);
+
+                for (i = part_len; i + 63 < len; i += 64)
+                        sha256_transform(sctx->state, &data[i]);
+                index = 0;
+        } else {
+                i = 0;
+        }
+
+        /* Buffer remaining input */
+        memcpy(&sctx->buf[index], &data[i], len-i);
+
+        return true;
+}
+
+SHA256SumValue SHA256Summation::Result()
+{
+   struct sha256_ctx *sctx = &Sum;
+   if (!Done) {
+        u8 bits[8];
+        unsigned int index, pad_len, t;
+        static const u8 padding[64] = { 0x80, };
+
+        /* Save number of bits */
+        t = sctx->count[0];
+        bits[7] = t; t >>= 8;
+        bits[6] = t; t >>= 8;
+        bits[5] = t; t >>= 8;
+        bits[4] = t;
+        t = sctx->count[1];
+        bits[3] = t; t >>= 8;
+        bits[2] = t; t >>= 8;
+        bits[1] = t; t >>= 8;
+        bits[0] = t;
+
+        /* Pad out to 56 mod 64. */
+        index = (sctx->count[0] >> 3) & 0x3f;
+        pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
+        Add(padding, pad_len);
+
+        /* Append length (before padding) */
+        Add(bits, 8);
+   }
+
+   Done = true;
+
+   /* Store state in digest */
+
+   SHA256SumValue res;
+   u8 *out = res.Sum;
+
+   int i, j;
+   unsigned int t;
+   for (i = j = 0; i < 8; i++, j += 4) {
+      t = sctx->state[i];
+      out[j+3] = t; t >>= 8;
+      out[j+2] = t; t >>= 8;
+      out[j+1] = t; t >>= 8;
+      out[j  ] = t;
+   }
+
+   return res;
+}
+
+// SHA256SumValue::SHA256SumValue - Constructs the sum from a string   /*{{{*/
+// ---------------------------------------------------------------------
+/* The string form of a SHA256 is a 64 character hex number */
+SHA256SumValue::SHA256SumValue(string Str)
+{
+   memset(Sum,0,sizeof(Sum));
+   Set(Str);
+}
+
+                                                                       /*}}}*/
+// SHA256SumValue::SHA256SumValue - Default constructor                /*{{{*/
+// ---------------------------------------------------------------------
+/* Sets the value to 0 */
+SHA256SumValue::SHA256SumValue()
+{
+   memset(Sum,0,sizeof(Sum));
+}
+
+                                                                       /*}}}*/
+// SHA256SumValue::Set - Set the sum from a string                     /*{{{*/
+// ---------------------------------------------------------------------
+/* Converts the hex string into a set of chars */
+bool SHA256SumValue::Set(string Str)
+{
+   return Hex2Num(Str,Sum,sizeof(Sum));
+}
+                                                                       /*}}}*/
+// SHA256SumValue::Value - Convert the number into a string            /*{{{*/
+// ---------------------------------------------------------------------
+/* Converts the set of chars into a hex string in lower case */
+string SHA256SumValue::Value() const
+{
+   char Conv[16] =
+      { '0','1','2','3','4','5','6','7','8','9','a','b',
+      'c','d','e','f'
+   };
+   char Result[65];
+   Result[64] = 0;
+
+   // Convert each char into two letters
+   int J = 0;
+   int I = 0;
+   for (; I != 64; J++,I += 2)
+   {
+      Result[I] = Conv[Sum[J] >> 4];
+      Result[I + 1] = Conv[Sum[J] & 0xF];
+   }
+
+   return string(Result);
+}
+
+
+
+// SHA256SumValue::operator == - Comparator                            /*{{{*/
+// ---------------------------------------------------------------------
+/* Call memcmp on the buffer */
+bool SHA256SumValue::operator == (const SHA256SumValue & rhs) const
+{
+   return memcmp(Sum,rhs.Sum,sizeof(Sum)) == 0;
+}
+                                                                       /*}}}*/
+
+
+// SHA256Summation::AddFD - Add content of file into the checksum      /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool SHA256Summation::AddFD(int Fd,unsigned long Size)
+{
+   unsigned char Buf[64 * 64];
+   int Res = 0;
+   int ToEOF = (Size == 0);
+   while (Size != 0 || ToEOF)
+   {
+      unsigned n = sizeof(Buf);
+      if (!ToEOF) n = min(Size,(unsigned long)n);
+      Res = read(Fd,Buf,n);
+      if (Res < 0 || (!ToEOF && (unsigned) Res != n)) // error, or short read
+         return false;
+      if (ToEOF && Res == 0) // EOF
+         break;
+      Size -= Res;
+      Add(Buf,Res);
+   }
+   return true;
+}
+                                                                       /*}}}*/
+
diff --git a/apt-pkg/contrib/sha256.h b/apt-pkg/contrib/sha256.h
new file mode 100644
index 000000000..9e88f5ece
--- /dev/null
+++ b/apt-pkg/contrib/sha256.h
@@ -0,0 +1,75 @@
+// -*- mode: cpp; mode: fold -*-
+// Description                                                          /*{{{*/
+// $Id: sha1.h,v 1.3 2001/05/07 05:05:47 jgg Exp $
+/* ######################################################################
+
+   SHA256SumValue - Storage for a SHA-256 hash.
+   SHA256Summation - SHA-256 Secure Hash Algorithm.
+   
+   This is a C++ interface to a set of SHA256Sum functions, that mirrors
+   the equivalent MD5 & SHA1 classes. 
+
+   ##################################################################### */
+                                                                        /*}}}*/
+#ifndef APTPKG_SHA256_H
+#define APTPKG_SHA256_H
+
+#ifdef __GNUG__
+#pragma interface "apt-pkg/sha256.h"
+#endif 
+
+#include <string>
+#include <algorithm>
+#include <stdint.h>
+
+using std::string;
+using std::min;
+
+class SHA256Summation;
+
+class SHA256SumValue
+{
+   friend class SHA256Summation;
+   unsigned char Sum[32];
+   
+   public:
+
+   // Accessors
+   bool operator ==(const SHA256SumValue &rhs) const; 
+   string Value() const;
+   inline void Value(unsigned char S[32])
+         {for (int I = 0; I != sizeof(Sum); I++) S[I] = Sum[I];};
+   inline operator string() const {return Value();};
+   bool Set(string Str);
+   inline void Set(unsigned char S[32]) 
+         {for (int I = 0; I != sizeof(Sum); I++) Sum[I] = S[I];};
+
+   SHA256SumValue(string Str);
+   SHA256SumValue();
+};
+
+struct sha256_ctx {
+    uint32_t count[2];
+    uint32_t state[8];
+    uint8_t buf[128];
+};
+
+class SHA256Summation
+{
+   struct sha256_ctx Sum;
+
+   bool Done;
+
+   public:
+
+   bool Add(const unsigned char *inbuf,unsigned long inlen);
+   inline bool Add(const char *Data) {return Add((unsigned char *)Data,strlen(Data));};
+   bool AddFD(int Fd,unsigned long Size);
+   inline bool Add(const unsigned char *Beg,const unsigned char *End) 
+                  {return Add(Beg,End-Beg);};
+   SHA256SumValue Result();
+   
+   SHA256Summation();
+};
+
+#endif