给定公共ECDSA密钥,我想验证某些有效负载的签名,并且我事先知道签名是正确的。我想使用cryptography python库,但问题是,即使签名应该正确,我也无法使验证工作正常进行并且始终会出现InvalidSignature
异常。
这里是我当前正在使用的代码段。公钥以base64编码且为DER格式(因此,没有---BEGIN PUBLIC KEY ---
等),签名也以base64编码。该消息是一些JSON数据作为字符串,没有空格。
import base64
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.backends import default_backend
def cryptography_verify(signature: str, public_key: str, message: str):
public = base64.b64decode(public_key)
pub = serialization.load_der_public_key(public, default_backend())
sig = base64.b64decode(signature)
msg = bytearray(message, 'utf-8')
return pub.verify(sig, msg, ec.ECDSA(hashes.SHA256()))
这将导致以下错误。
Traceback (most recent call last):
File "verify.py", line 49, in <module>
test()
File "verify.py", line 44, in test
print(cryptography_verify(signature, public_key, message))
File "verify.py", line 31, in cryptography_verify
return pub.verify(sig, msg, ec.ECDSA(hashes.SHA256()))
File "/home/philipp/.local/lib/python3.6/site-packages/cryptography/hazmat/backends/openssl/ec.py", line 352, in verify
_ecdsa_sig_verify(self._backend, self, signature, data)
File "/home/philipp/.local/lib/python3.6/site-packages/cryptography/hazmat/backends/openssl/ec.py", line 101, in _ecdsa_sig_verify
raise InvalidSignature
cryptography.exceptions.InvalidSignature
我知道签名肯定有效的原因是,因为我尝试了另一个名为ecdsa的库,因此可以在其中成功验证签名。这是该代码段。
import hashlib
import base64
import ecdsa
def ecdsa_verify(signature: str, public_key: str, message: str):
public = base64.b64decode(public_key)
pub = ecdsa.VerifyingKey.from_der(public)
sig = base64.b64decode(signature)
msg = bytearray(message, 'utf-8')
return pub.verify(sig, msg, hashfunc=hashlib.sha256)
这只会返回True
。我之所以不仅仅使用有效的解决方案,是因为最终必须使用cryptography
库,以获得ecdsa
无法提供的某些功能。另外,我不想将两个库用于相同的目的。
[进行了一些挖掘之后,尝试对哈希进行预哈希处理而没有任何积极结果,我尝试打印出两个反序列化密钥的公钥字节(表示pub
变量)。
# for ecdsa library
print(pub.to_string())
# for cryptography library
print(pub.public_bytes(serialization.Encoding.DER, serialization.PublicFormat.SubjectPublicKeyInfo))
有趣的是,以下内容表示。
# for ecdsa library
b'3Le\xf0^g\xc0\x85w \n\xee\xd4\xf7\xfc\xe5`\xa8\xe1\xc7\xd39\x0fu\x8e\x1cUi\r\xf1\x1c\xc7\x96\xe3}*\xed\x1e\x07\xfe\xd2f\x01u\x19\x05\xef\xa795\xfc\xa6\x0bf\xac\xbaS\xf8{\xbf\x1f\xbaT\x87'
# for cryptography library
b'0Y0\x13\x06\x07*\x86H\xce=\x02\x01\x06\x08*\x86H\xce=\x03\x01\x07\x03B\x00\x043Le\xf0^g\xc0\x85w \n\xee\xd4\xf7\xfc\xe5`\xa8\xe1\xc7\xd39\x0fu\x8e\x1cUi\r\xf1\x1c\xc7\x96\xe3}*\xed\x1e\x07\xfe\xd2f\x01u\x19\x05\xef\xa795\xfc\xa6\x0bf\xac\xbaS\xf8{\xbf\x1f\xbaT\x87'
意味着cryptography
库,与ecdsa
库相比,在公共密钥之前添加了一些字节。为什么以及如何防止这种情况?我觉得我只是在滥用该库,可以通过某种方式解决此问题,但我只是不知道如何。
Update1:为进一步说明,这里是验证方法的调用。
def test():
file_path = "sample.json"
with open(file_path, "r") as file:
file_json = json.load(file)
signature = '9CMVpSkDaKUmZFoluiURVyjJGZ3GgcY1ZopPmw8qR+TsbEH2wbh4zkZDHcNzvV8MeFVn2ln5PuLv2v/+24AMSg=='
public_key = 'MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEM0xl8F5nwIV3IAru1Pf85WCo4cfTOQ91jhxVaQ3xHMeW430q7R4H/tJmAXUZBe+nOTX8pgtmrLpT+Hu/H7pUhw=='
message = json.dumps(file_json, separators=(',', ':'))
print(ecdsa_verify(signature, public_key, message))
print()
print(cryptography_verify(signature, public_key, message))
return
sample.json
看起来像这样。
{
"_type": "Targets",
"delegations": {
"keys": {},
"roles": []
},
"expires": "2023-01-09T11:31:27.627615676+01:00",
"targets": {
"v1": {
"hashes": {
"sha256": "E4irx6ElMoNsOoG9sAh0CbFSCPWuunqHrtz9VtY3wUU="
},
"length": 1994
},
"v2": {
"hashes": {
"sha256": "uKOFIodqniVQ1YLOUaHYfr3GxXDl5YXQhWC/1kb3+AQ="
},
"length": 1994
}
},
"version": 2
}
据我所知,这两种方法都使用完全相同的输入,因此JSON消息中不应有任何区别。我还对反序列化的公钥进行了十六进制编码,请到这里。
# for ecdsa
334c65f05e67c08577200aeed4f7fce560a8e1c7d3390f758e1c55690df11cc796e37d2aed1e07fed26601751905efa73935fca60b66acba53f87bbf1fba5487
# for cryptography
3059301306072a8648ce3d020106082a8648ce3d03010703420004334c65f05e67c08577200aeed4f7fce560a8e1c7d3390f758e1c55690df11cc796e37d2aed1e07fed26601751905efa73935fca60b66acba53f87bbf1fba5487
您提供的签名格式不适合OpenSSL。可以通过增强OpenSSL引发错误时调用的加密方法来提取OpenSSL的错误:
def _consume_errors(lib):
errors = []
while True:
code = lib.ERR_get_error()
if code == 0:
break
print(hex(code)) # <-- ADD THIS
err_lib = lib.ERR_GET_LIB(code)
err_func = lib.ERR_GET_FUNC(code)
err_reason = lib.ERR_GET_REASON(code)
errors.append(_OpenSSLError(code, err_lib, err_func, err_reason))
print('ERROR: ', err_lib, err_func, err_reason)
return errors
您将收到错误代码d0680a8
和d07803a
,可以使用OpenSSL CLI进行翻译:
$ openssl errstr d0680a8
error:0D0680A8:asn1 encoding routines:asn1_check_tlen:wrong tag
$ openssl errstr d07803a
error:0D07803A:asn1 encoding routines:asn1_item_embed_d2i:nested asn1 error
您可以使用OpenSSL CLI达到相同的结果,完全避免使用加密库。为此,请将公钥存储在文件中:
$ cat pub.key
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEM0xl8F5nwIV3IAru1Pf85WCo4cfT
OQ91jhxVaQ3xHMeW430q7R4H/tJmAXUZBe+nOTX8pgtmrLpT+Hu/H7pUhw==
-----END PUBLIC KEY-----
将签名(经过base64解码的签名)存储在文件中:
echo -n '9CMVpSkDaKUmZFoluiURVyjJGZ3GgcY1ZopPmw8qR+TsbEH2wbh4zkZDHcNzvV8MeFVn2ln5PuLv2v/+24AMSg==' | base64 -d > sig
[通过比较OpenSSL计算的摘要来验证我们输入正确:
$ echo -ne '{"_type":"Targets","delegations":{"keys":{},"roles":[]},"expires":"2023-01-09T11:31:27.627615676+01:00","targets":{"v1":{"hashes":{"sha256":"E4irx6ElMoNsOoG9sAh0CbFSCPWuunqHrtz9VtY3wUU="},"length":1994},"v2":{"hashes":{"sha256":"uKOFIodqniVQ1YLOUaHYfr3GxXDl5YXQhWC/1kb3+AQ="},"length":1994}},"version":2}' | openssl dgst -sha256
(stdin)= e46bb43c417cac7d72ba24d48a7c5d669afaa88129f5a73ac3c7da1f9a3ae409
最后尝试检查签名:
$ echo -ne '{"_type":"Targets","delegations":{"keys":{},"roles":[]},"expires":"2023-01-09T11:31:27.627615676+01:00","targets":{"v1":{"hashes":{"sha256":"E4irx6ElMoNsOoG9sAh0CbFSCPWuunqHrtz9VtY3wUU="},"length":1994},"v2":{"hashes":{"sha256":"uKOFIodqniVQ1YLOUaHYfr3GxXDl5YXQhWC/1kb3+AQ="},"length":1994}},"version":2}' | openssl dgst -sha256 -verify pub.key -signature sig
Error Verifying Data
140338533991616:error:0D0680A8:asn1 encoding routines:asn1_check_tlen:wrong tag:../crypto/asn1/tasn_dec.c:1130:
140338533991616:error:0D07803A:asn1 encoding routines:asn1_item_embed_d2i:nested asn1 error:../crypto/asn1/tasn_dec.c:290:Type=ECDSA_SIG