diff --git a/fake-lib.c b/fake-lib.c
index 011d35d..f2c949b 100644
--- a/fake-lib.c
+++ b/fake-lib.c
@@ -140,3 +140,217 @@ unsigned le(const unsigned char *buf, size_t len, size_t off, size_t nbytes)
     }
     return toret;
 }
+
+/* ----------------------------------------------------------------------
+ * Core MD5 algorithm: processes 16-word blocks into a message digest.
+ */
+
+typedef struct {
+    uint32_t h[4];
+} MD5_Core_State;
+
+struct MD5Context {
+    MD5_Core_State core;
+    unsigned char block[64];
+    int blkused;
+    uint32_t lenhi, lenlo;
+};
+
+#define F(x,y,z) ( ((x) & (y)) | ((~(x)) & (z)) )
+#define G(x,y,z) ( ((x) & (z)) | ((~(z)) & (y)) )
+#define H(x,y,z) ( (x) ^ (y) ^ (z) )
+#define I(x,y,z) ( (y) ^ ( (x) | ~(z) ) )
+
+#define rol(x,y) ( ((x) << (y)) | (((uint32_t)x) >> (32-y)) )
+
+#define subround(f,w,x,y,z,k,s,ti) \
+       w = x + rol(w + f(x,y,z) + block[k] + ti, s)
+
+static void MD5_Core_Init(MD5_Core_State * s)
+{
+    s->h[0] = 0x67452301;
+    s->h[1] = 0xefcdab89;
+    s->h[2] = 0x98badcfe;
+    s->h[3] = 0x10325476;
+}
+
+static void MD5_Block(MD5_Core_State * s, uint32_t * block)
+{
+    uint32_t a, b, c, d;
+
+    a = s->h[0];
+    b = s->h[1];
+    c = s->h[2];
+    d = s->h[3];
+
+    subround(F, a, b, c, d, 0, 7, 0xd76aa478);
+    subround(F, d, a, b, c, 1, 12, 0xe8c7b756);
+    subround(F, c, d, a, b, 2, 17, 0x242070db);
+    subround(F, b, c, d, a, 3, 22, 0xc1bdceee);
+    subround(F, a, b, c, d, 4, 7, 0xf57c0faf);
+    subround(F, d, a, b, c, 5, 12, 0x4787c62a);
+    subround(F, c, d, a, b, 6, 17, 0xa8304613);
+    subround(F, b, c, d, a, 7, 22, 0xfd469501);
+    subround(F, a, b, c, d, 8, 7, 0x698098d8);
+    subround(F, d, a, b, c, 9, 12, 0x8b44f7af);
+    subround(F, c, d, a, b, 10, 17, 0xffff5bb1);
+    subround(F, b, c, d, a, 11, 22, 0x895cd7be);
+    subround(F, a, b, c, d, 12, 7, 0x6b901122);
+    subround(F, d, a, b, c, 13, 12, 0xfd987193);
+    subround(F, c, d, a, b, 14, 17, 0xa679438e);
+    subround(F, b, c, d, a, 15, 22, 0x49b40821);
+    subround(G, a, b, c, d, 1, 5, 0xf61e2562);
+    subround(G, d, a, b, c, 6, 9, 0xc040b340);
+    subround(G, c, d, a, b, 11, 14, 0x265e5a51);
+    subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa);
+    subround(G, a, b, c, d, 5, 5, 0xd62f105d);
+    subround(G, d, a, b, c, 10, 9, 0x02441453);
+    subround(G, c, d, a, b, 15, 14, 0xd8a1e681);
+    subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8);
+    subround(G, a, b, c, d, 9, 5, 0x21e1cde6);
+    subround(G, d, a, b, c, 14, 9, 0xc33707d6);
+    subround(G, c, d, a, b, 3, 14, 0xf4d50d87);
+    subround(G, b, c, d, a, 8, 20, 0x455a14ed);
+    subround(G, a, b, c, d, 13, 5, 0xa9e3e905);
+    subround(G, d, a, b, c, 2, 9, 0xfcefa3f8);
+    subround(G, c, d, a, b, 7, 14, 0x676f02d9);
+    subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a);
+    subround(H, a, b, c, d, 5, 4, 0xfffa3942);
+    subround(H, d, a, b, c, 8, 11, 0x8771f681);
+    subround(H, c, d, a, b, 11, 16, 0x6d9d6122);
+    subround(H, b, c, d, a, 14, 23, 0xfde5380c);
+    subround(H, a, b, c, d, 1, 4, 0xa4beea44);
+    subround(H, d, a, b, c, 4, 11, 0x4bdecfa9);
+    subround(H, c, d, a, b, 7, 16, 0xf6bb4b60);
+    subround(H, b, c, d, a, 10, 23, 0xbebfbc70);
+    subround(H, a, b, c, d, 13, 4, 0x289b7ec6);
+    subround(H, d, a, b, c, 0, 11, 0xeaa127fa);
+    subround(H, c, d, a, b, 3, 16, 0xd4ef3085);
+    subround(H, b, c, d, a, 6, 23, 0x04881d05);
+    subround(H, a, b, c, d, 9, 4, 0xd9d4d039);
+    subround(H, d, a, b, c, 12, 11, 0xe6db99e5);
+    subround(H, c, d, a, b, 15, 16, 0x1fa27cf8);
+    subround(H, b, c, d, a, 2, 23, 0xc4ac5665);
+    subround(I, a, b, c, d, 0, 6, 0xf4292244);
+    subround(I, d, a, b, c, 7, 10, 0x432aff97);
+    subround(I, c, d, a, b, 14, 15, 0xab9423a7);
+    subround(I, b, c, d, a, 5, 21, 0xfc93a039);
+    subround(I, a, b, c, d, 12, 6, 0x655b59c3);
+    subround(I, d, a, b, c, 3, 10, 0x8f0ccc92);
+    subround(I, c, d, a, b, 10, 15, 0xffeff47d);
+    subround(I, b, c, d, a, 1, 21, 0x85845dd1);
+    subround(I, a, b, c, d, 8, 6, 0x6fa87e4f);
+    subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0);
+    subround(I, c, d, a, b, 6, 15, 0xa3014314);
+    subround(I, b, c, d, a, 13, 21, 0x4e0811a1);
+    subround(I, a, b, c, d, 4, 6, 0xf7537e82);
+    subround(I, d, a, b, c, 11, 10, 0xbd3af235);
+    subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb);
+    subround(I, b, c, d, a, 9, 21, 0xeb86d391);
+
+    s->h[0] += a;
+    s->h[1] += b;
+    s->h[2] += c;
+    s->h[3] += d;
+}
+
+/* ----------------------------------------------------------------------
+ * Outer MD5 algorithm: take an arbitrary length byte string,
+ * convert it into 16-word blocks with the prescribed padding at
+ * the end, and pass those blocks to the core MD5 algorithm.
+ */
+
+#define BLKSIZE 64
+
+void MD5Init(struct MD5Context *s)
+{
+    MD5_Core_Init(&s->core);
+    s->blkused = 0;
+    s->lenhi = s->lenlo = 0;
+}
+
+void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len)
+{
+    unsigned char *q = (unsigned char *) p;
+    uint32_t wordblock[16];
+    uint32_t lenw = len;
+    int i;
+
+    /*
+     * Update the length field.
+     */
+    s->lenlo += lenw;
+    s->lenhi += (s->lenlo < lenw);
+
+    if (s->blkused + len < BLKSIZE) {
+	/*
+	 * Trivial case: just add to the block.
+	 */
+	memcpy(s->block + s->blkused, q, len);
+	s->blkused += len;
+    } else {
+	/*
+	 * We must complete and process at least one block.
+	 */
+	while (s->blkused + len >= BLKSIZE) {
+	    memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused);
+	    q += BLKSIZE - s->blkused;
+	    len -= BLKSIZE - s->blkused;
+	    /* Now process the block. Gather bytes little-endian into words */
+	    for (i = 0; i < 16; i++) {
+		wordblock[i] =
+		    (((uint32_t) s->block[i * 4 + 3]) << 24) |
+		    (((uint32_t) s->block[i * 4 + 2]) << 16) |
+		    (((uint32_t) s->block[i * 4 + 1]) << 8) |
+		    (((uint32_t) s->block[i * 4 + 0]) << 0);
+	    }
+	    MD5_Block(&s->core, wordblock);
+	    s->blkused = 0;
+	}
+	memcpy(s->block, q, len);
+	s->blkused = len;
+    }
+}
+
+void MD5Final(uint32_t output[4], struct MD5Context *s)
+{
+    int i;
+    unsigned pad;
+    unsigned char c[64];
+    uint32_t lenhi, lenlo;
+
+    if (s->blkused >= 56)
+	pad = 56 + 64 - s->blkused;
+    else
+	pad = 56 - s->blkused;
+
+    lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3));
+    lenlo = (s->lenlo << 3);
+
+    memset(c, 0, pad);
+    c[0] = 0x80;
+    MD5Update(s, c, pad);
+
+    c[7] = (lenhi >> 24) & 0xFF;
+    c[6] = (lenhi >> 16) & 0xFF;
+    c[5] = (lenhi >> 8) & 0xFF;
+    c[4] = (lenhi >> 0) & 0xFF;
+    c[3] = (lenlo >> 24) & 0xFF;
+    c[2] = (lenlo >> 16) & 0xFF;
+    c[1] = (lenlo >> 8) & 0xFF;
+    c[0] = (lenlo >> 0) & 0xFF;
+
+    MD5Update(s, c, 8);
+
+    for (i = 0; i < 4; i++)
+        output[i] = s->core.h[i];
+}
+
+void MD5Simple(void const *p, unsigned len, uint32_t output[4])
+{
+    struct MD5Context s;
+
+    MD5Init(&s);
+    MD5Update(&s, (unsigned char const *)p, len);
+    MD5Final(output, &s);
+}
diff --git a/fake-lib.h b/fake-lib.h
index 9dd8049..99a6eec 100644
--- a/fake-lib.h
+++ b/fake-lib.h
@@ -6,6 +6,7 @@ void *smalloc(size_t size);
 void *srealloc(void *ptr, size_t size);
 char *dupcat(const char *str, ...);
 unsigned le(const unsigned char *buf, size_t len, size_t off, size_t nbytes);
+void MD5Simple(void const *p, unsigned len, uint32_t output[4]);
 
 #define snew(type) ((type *)smalloc(sizeof(type)))
 #define snewn(n,type) ((type *)smalloc((n)*sizeof(type)))
diff --git a/fake-msi.c b/fake-msi.c
index 2ceab99..92c24e3 100644
--- a/fake-msi.c
+++ b/fake-msi.c
@@ -193,6 +193,44 @@ uint32_t MsiGetFileVersionW(const char16_t *filename,
     sfree(fname);
     return toret;
 }
+
+struct MsiHash {
+    uint32_t structure_size;
+    uint32_t hash_words[4];
+};
+
+uint32_t MsiGetFileHashW(const char16_t *filename, uint32_t options,
+                         struct MsiHash *hash)
+{
+    char *fname = ascii(filename, true);
+    int fd = -1;
+    void *mapv = MAP_FAILED;
+    uint32_t toret;
+
+    fd = open(fname, O_RDONLY);
+    if (fd < 0)
+        err(1, "%s: open", fname);
+    struct stat st;
+    if (fstat(fd, &st) < 0)
+        err(1, "%s: fstat", fname);
+    size_t fsize = st.st_size;
+    mapv = mmap(NULL, fsize, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (mapv == MAP_FAILED)
+        err(1, "%s: mmap", fname);
+
+    MD5Simple(mapv, fsize, hash->hash_words);
+    warnx("MsiGetFileHash(%s) -> %08x:%08x:%08x:%08x", fname,
+          (unsigned)hash->hash_words[0], (unsigned)hash->hash_words[1],
+          (unsigned)hash->hash_words[2], (unsigned)hash->hash_words[3]);
+    toret = 0;
+
+  cleanup:
+    if (mapv != MAP_FAILED)
+        munmap(mapv, fsize);
+    if (fd != -1)
+        close(fd);
+    sfree(fname);
+    return toret;
 }
 
 typedef struct MsiTypePrefix {