机构信息离线验证在线验证

浏览器对证书链的合法性检查通过后会再检查服务端证书附件里的SCT列表Signed

Certificate

log机构的公钥和访问地址如果SCT申明证书在某个log机构注册了但是SCT里的签名通过不了log机构的公钥验证则抛出错误NET::ERR_CERTIFICATE_TRANSPARENCY_REQUIRED

验证SCT

使用github.com/google/certificate-transparency-go工具

import

(contextencoding/base64encoding/pemerrorsiolognet/httpostimect

github.com/google/certificate-transparency-gogithub.com/google/certificate-transparency-go/ctutilgithub.com/google/certificate-transparency-go/loglist3ctX509

github.com/google/certificate-transparency-go/x509github.com/google/certificate-transparency-go/x509util

)加载证书

假设服务端证书以及签发该证书的上级CA证书已保存为PEM格式的文件

func

ctX509.ParseCertificate(block.Bytes)if

err

os.ReadFile(issuerLocation)block,

block

ctX509.ParseCertificate(block.Bytes)err

cert.CheckSignatureFrom(issuer)if

err

{log.Printf(证书%s的签名算法是%sCA签名没有验证成功,

cert.Subject,

cert.SignatureAlgorithm.String())return

err}//

ct.MerkleTreeLeafForEmbeddedSCT([]*ctX509.Certificate{cert,

issuer},

x509util.ParseSCTsFromSCTList(cert.SCTList)if

err

使用和chrome一致的机构列表https://www.gstatic.com/ct/log_list/v3/log_list.json

transparency

http.DefaultClient.Get(loglist3.LogListURL)if

err

loglist3.NewFromJSON(body)logsByHash,

ctutil.LogInfoByKeyHash(loglistEntry,

logInfo.VerifySCTSignature方法不需要和log机构在线交互是使用已知的log机构公钥对SCT进行离线验证

ctx,

context.WithTimeout(context.Background(),

10*time.Second)defer

验证sct参考https://github.com/google/certificate-transparency-go/blob/master/ctutil/sctscan/sctscan.golog.Printf(sct

signature:

base64.StdEncoding.EncodeToString(sct.Signature.Signature),

time.Unix(0,

int64(sct.Timestamp)*int64(time.Millisecond)).Format(time.RFC3339Nano))logInfo,

!ok

base64.StdEncoding.EncodeToString(sct.LogID.KeyID[:]))continue}log.Printf(颁发sct的certificate

transparency

logInfo.Description,logInfo.Client.BaseURI(),

base64.StdEncoding.EncodeToString(sct.LogID.KeyID[:]))err

logInfo.VerifySCTSignature(*sct,

*merkleLeaf)if

err)continue}log.Println(Verify

SCT

logInfo.VerifyInclusionLatest(ctx,

*merkleLeaf,

time.Duration(sth.Timestamp-sct.Timestamp)

time.Millisecondif

如果生效时间logInfo.MMD还未到那么机构查询不到该sct的merkle

tree

logInfo.MMD)continue}}log.Printf(Failed

verify

每个SCT分别是不同log机构签发的如果一个证书附带的两个SCT是由同一个log机构签发或者SCT列表涉及的log机构合计不足3个浏览器似乎也会报错

目前证书检查通过后chrome的F12里才显示解析的SCT列表ERR_CERTIFICATE_TRANSPARENCY_REQUIRED错误发生时需要使用这个程序来查看SCT列表里是否存在重复注册、注册的log机构数量不足甚至是否无法通过SCT签名检查