diff --git a/auto/sources b/auto/sources
index 27849e6..216e900 100644
--- a/auto/sources
+++ b/auto/sources
@@ -61,6 +61,7 @@
            src/core/ngx_crc32.c \
            src/core/ngx_murmurhash.c \
            src/core/ngx_md5.c \
+           src/core/ngx_sha1.c \
            src/core/ngx_rbtree.c \
            src/core/ngx_radix_tree.c \
            src/core/ngx_slab.c \
diff --git a/src/core/ngx_crypt.c b/src/core/ngx_crypt.c
index 9db74f4..868dc5d 100644
--- a/src/core/ngx_crypt.c
+++ b/src/core/ngx_crypt.c
@@ -8,9 +8,7 @@
 #include <ngx_core.h>
 #include <ngx_crypt.h>
 #include <ngx_md5.h>
-#if (NGX_HAVE_SHA1)
 #include <ngx_sha1.h>
-#endif
 
 
 #if (NGX_CRYPT)
@@ -19,16 +17,11 @@
     u_char **encrypted);
 static ngx_int_t ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt,
     u_char **encrypted);
-
-#if (NGX_HAVE_SHA1)
-
 static ngx_int_t ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt,
     u_char **encrypted);
 static ngx_int_t ngx_crypt_sha(ngx_pool_t *pool, u_char *key, u_char *salt,
     u_char **encrypted);
 
-#endif
-
 
 static u_char *ngx_crypt_to64(u_char *p, uint32_t v, size_t n);
 
@@ -42,13 +35,11 @@
     } else if (ngx_strncmp(salt, "{PLAIN}", sizeof("{PLAIN}") - 1) == 0) {
         return ngx_crypt_plain(pool, key, salt, encrypted);
 
-#if (NGX_HAVE_SHA1)
     } else if (ngx_strncmp(salt, "{SSHA}", sizeof("{SSHA}") - 1) == 0) {
         return ngx_crypt_ssha(pool, key, salt, encrypted);
 
     } else if (ngx_strncmp(salt, "{SHA}", sizeof("{SHA}") - 1) == 0) {
         return ngx_crypt_sha(pool, key, salt, encrypted);
-#endif
     }
 
     /* fallback to libc crypt() */
@@ -193,8 +184,6 @@
 }
 
 
-#if (NGX_HAVE_SHA1)
-
 static ngx_int_t
 ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
 {
@@ -278,6 +267,4 @@
     return NGX_OK;
 }
 
-#endif /* NGX_HAVE_SHA1 */
-
 #endif /* NGX_CRYPT */
diff --git a/src/core/ngx_sha1.c b/src/core/ngx_sha1.c
new file mode 100644
index 0000000..fd665fd
--- /dev/null
+++ b/src/core/ngx_sha1.c
@@ -0,0 +1,300 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ *
+ * An internal SHA1 implementation.
+ * It is not expected to be optimal and is used only
+ * if no SHA1 implementation was found in system.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_sha1.h>
+
+
+#if !(NGX_HAVE_SHA1)
+
+static const u_char *ngx_sha1_body(ngx_sha1_t *ctx, const u_char *data,
+    size_t size);
+
+
+void
+ngx_sha1_init(ngx_sha1_t *ctx)
+{
+    ctx->a = 0x67452301;
+    ctx->b = 0xefcdab89;
+    ctx->c = 0x98badcfe;
+    ctx->d = 0x10325476;
+    ctx->e = 0xc3d2e1f0;
+
+    ctx->bytes = 0;
+}
+
+
+void
+ngx_sha1_update(ngx_sha1_t *ctx, const void *data, size_t size)
+{
+    size_t  used, free;
+
+    used = (size_t) (ctx->bytes & 0x3f);
+    ctx->bytes += size;
+
+    if (used) {
+        free = 64 - used;
+
+        if (size < free) {
+            ngx_memcpy(&ctx->buffer[used], data, size);
+            return;
+        }
+
+        ngx_memcpy(&ctx->buffer[used], data, free);
+        data = (u_char *) data + free;
+        size -= free;
+        (void) ngx_sha1_body(ctx, ctx->buffer, 64);
+    }
+
+    if (size >= 64) {
+        data = ngx_sha1_body(ctx, data, size & ~(size_t) 0x3f);
+        size &= 0x3f;
+    }
+
+    ngx_memcpy(ctx->buffer, data, size);
+}
+
+
+void
+ngx_sha1_final(u_char result[20], ngx_sha1_t *ctx)
+{
+    size_t  used, free;
+
+    used = (size_t) (ctx->bytes & 0x3f);
+
+    ctx->buffer[used++] = 0x80;
+
+    free = 64 - used;
+
+    if (free < 8) {
+        ngx_memzero(&ctx->buffer[used], free);
+        (void) ngx_sha1_body(ctx, ctx->buffer, 64);
+        used = 0;
+        free = 64;
+    }
+
+    ngx_memzero(&ctx->buffer[used], free - 8);
+
+    ctx->bytes <<= 3;
+    ctx->buffer[56] = (u_char) (ctx->bytes >> 56);
+    ctx->buffer[57] = (u_char) (ctx->bytes >> 48);
+    ctx->buffer[58] = (u_char) (ctx->bytes >> 40);
+    ctx->buffer[59] = (u_char) (ctx->bytes >> 32);
+    ctx->buffer[60] = (u_char) (ctx->bytes >> 24);
+    ctx->buffer[61] = (u_char) (ctx->bytes >> 16);
+    ctx->buffer[62] = (u_char) (ctx->bytes >> 8);
+    ctx->buffer[63] = (u_char) ctx->bytes;
+
+    (void) ngx_sha1_body(ctx, ctx->buffer, 64);
+
+    result[0] = (u_char) (ctx->a >> 24);
+    result[1] = (u_char) (ctx->a >> 16);
+    result[2] = (u_char) (ctx->a >> 8);
+    result[3] = (u_char) ctx->a;
+    result[4] = (u_char) (ctx->b >> 24);
+    result[5] = (u_char) (ctx->b >> 16);
+    result[6] = (u_char) (ctx->b >> 8);
+    result[7] = (u_char) ctx->b;
+    result[8] = (u_char) (ctx->c >> 24);
+    result[9] = (u_char) (ctx->c >> 16);
+    result[10] = (u_char) (ctx->c >> 8);
+    result[11] = (u_char) ctx->c;
+    result[12] = (u_char) (ctx->d >> 24);
+    result[13] = (u_char) (ctx->d >> 16);
+    result[14] = (u_char) (ctx->d >> 8);
+    result[15] = (u_char) ctx->d;
+    result[16] = (u_char) (ctx->e >> 24);
+    result[17] = (u_char) (ctx->e >> 16);
+    result[18] = (u_char) (ctx->e >> 8);
+    result[19] = (u_char) ctx->e;
+
+    ngx_memzero(ctx, sizeof(*ctx));
+}
+
+
+/*
+ * Helper functions.
+ */
+
+#define ROTATE(bits, word)  (((word) << (bits)) | ((word) >> (32 - (bits))))
+
+#define F1(b, c, d)  (((b) & (c)) | ((~(b)) & (d)))
+#define F2(b, c, d)  ((b) ^ (c) ^ (d))
+#define F3(b, c, d)  (((b) & (c)) | ((b) & (d)) | ((c) & (d)))
+
+#define STEP(f, a, b, c, d, e, w, t)                                          \
+    temp = ROTATE(5, (a)) + f((b), (c), (d)) + (e) + (w) + (t);               \
+    (e) = (d);                                                                \
+    (d) = (c);                                                                \
+    (c) = ROTATE(30, (b));                                                    \
+    (b) = (a);                                                                \
+    (a) = temp;
+
+
+/*
+ * GET() reads 4 input bytes in big-endian byte order and returns
+ * them as uint32_t.
+ */
+
+#define GET(n)                                                                \
+    ((uint32_t) p[n * 4 + 3] |                                                \
+    ((uint32_t) p[n * 4 + 2] << 8) |                                          \
+    ((uint32_t) p[n * 4 + 1] << 16) |                                         \
+    ((uint32_t) p[n * 4] << 24))
+
+
+/*
+ * This processes one or more 64-byte data blocks, but does not update
+ * the bit counters.  There are no alignment requirements.
+ */
+
+static const u_char *
+ngx_sha1_body(ngx_sha1_t *ctx, const u_char *data, size_t size)
+{
+    uint32_t       a, b, c, d, e, temp;
+    uint32_t       saved_a, saved_b, saved_c, saved_d, saved_e;
+    uint32_t       words[80];
+    ngx_uint_t     i;
+    const u_char  *p;
+
+    p = data;
+
+    a = ctx->a;
+    b = ctx->b;
+    c = ctx->c;
+    d = ctx->d;
+    e = ctx->e;
+
+    do {
+        saved_a = a;
+        saved_b = b;
+        saved_c = c;
+        saved_d = d;
+        saved_e = e;
+
+        /* Load data block into the words array */
+
+        for (i = 0; i < 16; i++) {
+            words[i] = GET(i);
+        }
+
+        for (i = 16; i < 80; i++) {
+            words[i] = ROTATE(1, words[i - 3] ^ words[i - 8] ^ words[i - 14]
+                                 ^ words[i - 16]);
+        }
+
+        /* Transformations */
+
+        STEP(F1, a, b, c, d, e, words[0],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[1],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[2],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[3],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[4],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[5],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[6],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[7],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[8],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[9],  0x5a827999);
+        STEP(F1, a, b, c, d, e, words[10], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[11], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[12], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[13], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[14], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[15], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[16], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[17], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[18], 0x5a827999);
+        STEP(F1, a, b, c, d, e, words[19], 0x5a827999);
+
+        STEP(F2, a, b, c, d, e, words[20], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[21], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[22], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[23], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[24], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[25], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[26], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[27], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[28], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[29], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[30], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[31], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[32], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[33], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[34], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[35], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[36], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[37], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[38], 0x6ed9eba1);
+        STEP(F2, a, b, c, d, e, words[39], 0x6ed9eba1);
+
+        STEP(F3, a, b, c, d, e, words[40], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[41], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[42], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[43], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[44], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[45], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[46], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[47], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[48], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[49], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[50], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[51], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[52], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[53], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[54], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[55], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[56], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[57], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[58], 0x8f1bbcdc);
+        STEP(F3, a, b, c, d, e, words[59], 0x8f1bbcdc);
+
+        STEP(F2, a, b, c, d, e, words[60], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[61], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[62], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[63], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[64], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[65], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[66], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[67], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[68], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[69], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[70], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[71], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[72], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[73], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[74], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[75], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[76], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[77], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[78], 0xca62c1d6);
+        STEP(F2, a, b, c, d, e, words[79], 0xca62c1d6);
+
+        a += saved_a;
+        b += saved_b;
+        c += saved_c;
+        d += saved_d;
+        e += saved_e;
+
+        p += 64;
+
+    } while (size -= 64);
+
+    ctx->a = a;
+    ctx->b = b;
+    ctx->c = c;
+    ctx->d = d;
+    ctx->e = e;
+
+    return p;
+}
+
+#endif
diff --git a/src/core/ngx_sha1.h b/src/core/ngx_sha1.h
index 81c909e..7fe4c98 100644
--- a/src/core/ngx_sha1.h
+++ b/src/core/ngx_sha1.h
@@ -13,6 +13,8 @@
 #include <ngx_core.h>
 
 
+#if (NGX_HAVE_SHA1)
+
 #if (NGX_HAVE_OPENSSL_SHA1_H)
 #include <openssl/sha.h>
 #else
@@ -28,4 +30,21 @@
 #define ngx_sha1_final   SHA1_Final
 
 
+#else /* !NGX_HAVE_SHA1 */
+
+
+typedef struct {
+    uint64_t  bytes;
+    uint32_t  a, b, c, d, e, f;
+    u_char    buffer[64];
+} ngx_sha1_t;
+
+
+void ngx_sha1_init(ngx_sha1_t *ctx);
+void ngx_sha1_update(ngx_sha1_t *ctx, const void *data, size_t size);
+void ngx_sha1_final(u_char result[20], ngx_sha1_t *ctx);
+
+
+#endif
+
 #endif /* _NGX_SHA1_H_INCLUDED_ */