commit 946c2eb4f0df0606686b4a378003e22a1de76034
Author: Vincent Reydet <toubib.lag@gmail.com>
Date:   Fri Aug 14 15:52:19 2015 +0200

    Create URL signing page

diff --git a/URL-signing.md b/URL-signing.md
new file mode 100644
index 0000000..9176941
--- /dev/null
+++ b/URL-signing.md
@@ -0,0 +1,80 @@
+# How to generate signed requests
+
+## Go
+
+main.go:
+```go
+package main
+
+import (
+        "os"
+        "fmt"
+        "crypto/hmac"
+        "crypto/sha256"
+        "encoding/base64"
+)
+
+func main() {
+        mac := hmac.New(sha256.New, []byte(os.Args[1]))
+        mac.Write([]byte(os.Args[2]))
+        want := mac.Sum(nil)
+        fmt.Println("result: ",base64.URLEncoding.EncodeToString(want))
+}
+```
+
+```shell
+$ go run main.go "test" "https://www.google.fr/images/srpr/logo11w.png"
+result:  RYifAJRfbhsitJeOrDNxWURCCkPsVR4ihCPXNv-ePbA=
+```
+
+## Bash
+
+```shell
+$ echo -n "https://www.google.fr/images/srpr/logo11w.png" | openssl dgst -sha256 -hmac "test" -binary|base64| tr '/+' '_-'
+RYifAJRfbhsitJeOrDNxWURCCkPsVR4ihCPXNv-ePbA=
+```
+
+## Java
+
+```java
+import org.apache.commons.codec.binary.Base64;
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+class EncodeUrl {
+
+  public static String encode(String key, String data) throws Exception {
+    Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
+    SecretKeySpec secret_key = new SecretKeySpec(key.getBytes(), "HmacSHA256");
+    sha256_HMAC.init(secret_key);
+
+    return Base64.encodeBase64URLSafeString(sha256_HMAC.doFinal(data.getBytes()));
+  }
+
+  public static void main(String [] args) throws Exception {
+    System.out.println(encode(args[0], args[1]));
+  }
+
+}
+```
+
+```shell
+$ java -cp commons-codec-1.10.jar:. EncodeUrl test https://www.google.fr/images/srpr/logo11w.png
+RYifAJRfbhsitJeOrDNxWURCCkPsVR4ihCPXNv-ePbA
+```
+
+## Ruby
+
+```ruby
+require 'openssl'
+require 'Base64'
+
+key = "test"
+data = "https://www.google.fr/images/srpr/logo11w.png"
+puts Base64.urlsafe_encode64(OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), key, data)).strip()
+```
+
+```shell
+% ruby sign.rb
+RYifAJRfbhsitJeOrDNxWURCCkPsVR4ihCPXNv-ePbA=
+```
\ No newline at end of file