new file mode 100644
--- /dev/null
+++ b/src/core/ngx_crypt.c
@@ -0,0 +1,234 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_md5.h>
+#if (NGX_HAVE_SHA1)
+#include <ngx_sha1.h>
+#endif
+
+
+static ngx_int_t ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt,
+    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);
+
+#endif
+
+
+static u_char *ngx_crypt_to64(u_char *p, uint32_t v, size_t n);
+
+
+ngx_int_t
+ngx_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    if (ngx_strncmp(salt, "$apr1$", sizeof("$apr1$") - 1) == 0) {
+        return ngx_crypt_apr1(pool, key, salt, encrypted);
+
+    } 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);
+#endif
+    }
+
+    /* fallback to libc crypt() */
+
+    return ngx_libc_crypt(pool, key, salt, encrypted);
+}
+
+
+static ngx_int_t
+ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    ngx_int_t          n;
+    ngx_uint_t         i;
+    u_char            *p, *last, final[16];
+    size_t             saltlen, keylen;
+    ngx_md5_t          md5, ctx1;
+
+    /* Apache's apr1 crypt is Paul-Henning Kamp's md5 crypt with $apr1$ magic */
+
+    keylen = ngx_strlen(key);
+
+    /* true salt: no magic, max 8 chars, stop at first $ */
+
+    salt += sizeof("$apr1$") - 1;
+    last = salt + 8;
+    for (p = salt; *p && *p != '$' && p < last; p++) { /* void */ }
+    saltlen = p - salt;
+
+    /* hash key and salt */
+
+    ngx_md5_init(&md5);
+    ngx_md5_update(&md5, key, keylen);
+    ngx_md5_update(&md5, "$apr1$", sizeof("$apr1$") - 1);
+    ngx_md5_update(&md5, salt, saltlen);
+
+    ngx_md5_init(&ctx1);
+    ngx_md5_update(&ctx1, key, keylen);
+    ngx_md5_update(&ctx1, salt, saltlen);
+    ngx_md5_update(&ctx1, key, keylen);
+    ngx_md5_final(final, &ctx1);
+
+    for (n = keylen; n > 0; n -= 16) {
+        ngx_md5_update(&md5, final, n > 16 ? 16 : n);
+    }
+
+    ngx_memzero(final, sizeof(final));
+
+    for (i = keylen; i; i >>= 1) {
+        if (i & 1) {
+            ngx_md5_update(&md5, final, 1);
+
+        } else {
+            ngx_md5_update(&md5, key, 1);
+        }
+    }
+
+    ngx_md5_final(final, &md5);
+
+    for (i = 0; i < 1000; i++) {
+        ngx_md5_init(&ctx1);
+
+        if (i & 1) {
+            ngx_md5_update(&ctx1, key, keylen);
+
+        } else {
+            ngx_md5_update(&ctx1, final, 16);
+        }
+
+        if (i % 3) {
+            ngx_md5_update(&ctx1, salt, saltlen);
+        }
+
+        if (i % 7) {
+            ngx_md5_update(&ctx1, key, keylen);
+        }
+
+        if (i & 1) {
+            ngx_md5_update(&ctx1, final, 16);
+
+        } else {
+            ngx_md5_update(&ctx1, key, keylen);
+        }
+
+        ngx_md5_final(final, &ctx1);
+    }
+
+    /* output */
+
+    *encrypted = ngx_pnalloc(pool, sizeof("$apr1$") - 1 + saltlen + 16 + 1);
+    if (*encrypted == NULL) {
+        return NGX_ERROR;
+    }
+
+    p = ngx_cpymem(*encrypted, "$apr1$", sizeof("$apr1$") - 1);
+    p = ngx_copy(p, salt, saltlen);
+    *p++ = '$';
+
+    p = ngx_crypt_to64(p, (final[ 0]<<16) | (final[ 6]<<8) | final[12], 4);
+    p = ngx_crypt_to64(p, (final[ 1]<<16) | (final[ 7]<<8) | final[13], 4);
+    p = ngx_crypt_to64(p, (final[ 2]<<16) | (final[ 8]<<8) | final[14], 4);
+    p = ngx_crypt_to64(p, (final[ 3]<<16) | (final[ 9]<<8) | final[15], 4);
+    p = ngx_crypt_to64(p, (final[ 4]<<16) | (final[10]<<8) | final[ 5], 4);
+    p = ngx_crypt_to64(p, final[11], 2);
+    *p = '\0';
+
+    return NGX_OK;
+}
+
+
+static u_char *
+ngx_crypt_to64(u_char *p, uint32_t v, size_t n)
+{
+    static u_char   itoa64[] =
+        "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+    while (n--) {
+       *p++ = itoa64[v & 0x3f];
+       v >>= 6;
+    }
+
+    return p;
+}
+
+
+static ngx_int_t
+ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    size_t   len;
+    u_char  *p;
+
+    len = ngx_strlen(key);
+
+    *encrypted = ngx_pnalloc(pool, sizeof("{PLAIN}") - 1 + len + 1);
+    if (*encrypted == NULL) {
+        return NGX_ERROR;
+    }
+
+    p = ngx_cpymem(*encrypted, "{PLAIN}", sizeof("{PLAIN}") - 1);
+    ngx_memcpy(p, key, len + 1);
+
+    return NGX_OK;
+}
+
+
+#if (NGX_HAVE_SHA1)
+
+static ngx_int_t
+ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    size_t       len;
+    ngx_str_t    encoded, decoded;
+    ngx_sha1_t   sha1;
+
+    /* "{SSHA}" base64(SHA1(key salt) salt) */
+
+    /* decode base64 salt to find out true salt */
+
+    encoded.data = salt + sizeof("{SSHA}") - 1;
+    encoded.len = ngx_strlen(encoded.data);
+
+    decoded.data = ngx_pnalloc(pool, ngx_base64_decoded_length(encoded.len));
+    if (decoded.data == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_decode_base64(&decoded, &encoded);
+
+    /* update SHA1 from key and salt */
+
+    ngx_sha1_init(&sha1);
+    ngx_sha1_update(&sha1, key, ngx_strlen(key));
+    ngx_sha1_update(&sha1, decoded.data + 20, decoded.len - 20);
+    ngx_sha1_final(decoded.data, &sha1);
+
+    /* encode it back to base64 */
+
+    len = sizeof("{SSHA}") - 1 + ngx_base64_encoded_length(decoded.len) + 1;
+
+    *encrypted = ngx_pnalloc(pool, len);
+    if (*encrypted == NULL) {
+        return NGX_ERROR;
+    }
+
+    encoded.data = ngx_cpymem(*encrypted, "{SSHA}", sizeof("{SSHA}") - 1);
+    ngx_encode_base64(&encoded, &decoded);
+    encoded.data[encoded.len] = '\0';
+
+    return NGX_OK;
+}
+
+#endif /* NGX_HAVE_SHA1 */