亚马逊AWS签名V4 Java给出错误的编码

Question

我正在尝试创建一个简单的表单，以使用AWS签名V4直接从我的浏览器将对象发布到S3中的存储桶。

我使用Java为预签名表单生成策略和签名值。现在，我只想测试它的工作原理，所以我不介意这是一个手动签名生成过程。

我的Java代码如下

import org.apache.commons.codec.binary.Base64; 
import org.apache.commons.codec.binary.Hex; 

import javax.crypto.Mac; 
import javax.crypto.spec.SecretKeySpec; 

public class Lala {  
    static String policy_document = "{ \"expiration\": \"2015-12-30T12:00:00.000Z\"," + 
      " \"conditions\": [" + 
      " {\"bucket\": \"sigv4examplebucket\"}," + 
      " [\"starts-with\", \"$key\", \"user/user1/\"]," + 
      " {\"acl\": \"public-read\"}," + 
      " {\"success_action_redirect\": \"http://sigv4examplebucket.s3.amazonaws.com/successful_upload.html\"}," + 
      " [\"starts-with\", \"$Content-Type\", \"image/\"]," + 
      " {\"x-amz-meta-uuid\": \"14365123651274\"}," + 
      " {\"x-amz-server-side-encryption\": \"AES256\"}," + 
      " [\"starts-with\", \"$x-amz-meta-tag\", \"\"]," + 
      " {\"x-amz-credential\": \"AKIAIOSFODNN7EXAMPLE/20151229/us-east-1/s3/aws4_request\"}," + 
      " {\"x-amz-algorithm\": \"AWS4-HMAC-SHA256\"}," + 
      " {\"x-amz-date\": \"20151229T000000Z\" }" + 
      " ]" + 
      "}"; 

    static String secret_key = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"; 

    public static void main(String[] args) throws Exception { 
     // Create a policy using UTF-8 encoding. 
     byte[] utf8_policy = policy_document.getBytes("UTF-8"); 

     // Convert the UTF-8-encoded policy bytes to Base64. The result is the StringToSign. 
     String base64_policy = new String(Base64.encodeBase64(utf8_policy)); 

     // Create a signing key. 
     byte[] signing_key = getSignatureKey(secret_key , "20151229", "us-east-1", "s3"); 

     // Use the signing key to sign the StringToSign using HMAC-SHA256 signing algorithm. 
     byte[] signature_bytes = HmacSHA256(base64_policy, signing_key); 
     String signature = Hex.encodeHexString(signature_bytes); 

     System.out.println(base64_policy); 
     System.out.println(); 
     System.out.println(signature); 
    } 

    static byte[] getSignatureKey(String key, String dateStamp, String regionName, String serviceName) throws Exception { 
     byte[] kSecret = ("AWS4" + key).getBytes("UTF-8"); 
     byte[] kDate = HmacSHA256(dateStamp, kSecret); 
     byte[] kRegion = HmacSHA256(regionName, kDate); 
     byte[] kService = HmacSHA256(serviceName, kRegion); 
     byte[] kSigning = HmacSHA256("aws4_request", kService); 
     return kSigning; 
    } 

    static byte[] HmacSHA256(String data, byte[] key) throws Exception { 
     String algorithm="HmacSHA256"; 
     Mac mac = Mac.getInstance(algorithm); 
     mac.init(new SecretKeySpec(key, algorithm)); 
     return mac.doFinal(data.getBytes("UTF-8")); 
    } 
} 

的政策文件和访问/密钥对从亚马逊的例子here所有拍摄。

我的代码还给下面的Base64编码政策：

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 ETk43RVhBTVBMRS8yMDE1MTIyOS91cy1lYXN0LTEvczMvYXdzNF9yZXF1ZXN0In0sICAgIHsieC1hbXotYWxnb3JpdGhtIjogIkFXUzQtSE1BQy1TSEEyNTYifSwgICAgeyJ4LWFtei1kYXRlIjogIjIwMTUxMjI5VDAwMDAwMFoiIH0gIF19

和下面的签名为它

1df5972015a56d4fdef92944436b91ce1f39b5cc684dcce9f4dab74b82734e84

其是从由亚马逊在上面的链接提供的不同。

我错过了什么吗？我有一种感觉，即policy_document变量中的String格式可能会让事情变得糟糕，但无论我如何格式化它（即新行，转义等），我似乎无法使其工作。

Answer 1

解码亚马逊的和你的，他们是不一样的，主要是格式。简单的格式差异会导致不同的签名散列。

在你的情况下，你需要在每行的末尾添加换行符。

亚马逊

 
{ "expiration": "2015-12-30T12:00:00.000Z", 
    "conditions": [ 
    {"bucket": "sigv4examplebucket"}, 
    ["starts-with", "$key", "user/user1/"], 
    {"acl": "public-read"}, 
    {"success_action_redirect": "http://sigv4examplebucket.s3.amazonaws.com/successful_upload.html"}, 
    ["starts-with", "$Content-Type", "image/"], 
    {"x-amz-meta-uuid": "14365123651274"}, 
    {"x-amz-server-side-encryption": "AES256"}, 
    ["starts-with", "$x-amz-meta-tag", ""], 

    {"x-amz-credential": "AKIAIOSFODNN7EXAMPLE/20151229/us-east-1/s3/aws4_request"}, 
    {"x-amz-algorithm": "AWS4-HMAC-SHA256"}, 
    {"x-amz-date": "20151229T000000Z" } 
    ] 
} 

此致：

 
{ "expiration": "2015-12-30T12:00:00.000Z", "conditions": [ {"bucket": "sigv4examplebucket"}, ["starts-with", "$key", "user/user1/"], {"acl": "public-read"}, {"success_action_redirect": "http://sigv4examplebucket.s3.amazonaws.com/successful_upload.html"}, ["starts-with", "$Content-Type", "image/"], {"x-amz-meta-uuid": "14365123651274"}, {"x-amz-server-side-encryption": "AES256"}, ["starts-with", "$x-amz-meta-tag", ""], {"x-amz-credential": "AKIAIOSFODNN7EXAMPLE/20151229/us-east-1/s3/aws4_request"}, {"x-amz-algorithm": "AWS4-HMAC-SHA256"}, {"x-amz-date": "20151229T000000Z" } ]} 
'