无法针对python/m2crypto中的DSA公钥验证dsawithSha1签名的消息 [英] failed to verify a dsawithSha1 signed message against a DSA public key in python/m2crypto
问题描述
- 我正在尝试使用持有dsa公钥的x509证书来验证签名消息. x509证书是由SAP System以PKCS7编码提供的，并且在使用openssl在PEM中进行转换后，我能够读取内容(openssl x509 -in sapcert.pem -inform pem -text) 它在dsaEncryption中拥有一个公共密钥，向我显示了DSA参数y(pub)，p，q和g.
因为我没有在M2Crypto x509类中找到DSA实现，所以我尝试自己构建DSA公钥.为此，我修补了MyCrypto，(请参阅: M2Crypto:验证DSA签名)
在这一点上，我坚持了几天尝试验证signedMessage的方法，希望在那里有一位冰冻专家可以帮助我.我尝试了很多，然后用谷歌搜索，尝试了pyCrypto lib，但都没有成功.
我试图将SHA1 MessageDigest和r和s值传递给M2Crypto.DSA.verify函数，但是由于失败，我想我要么必须传递signedMessage要么传递它的一部分. (在一个Java论坛中，我发现了一些有关验证SAP提供的signedMessages的帖子，还有一些关于通过"DER编码"计算签名的信息. 的签名属性."?)
这是我的示例代码:
# -*- coding: iso-8859-1 -*-
import M2Crypto
import urllib
import base64
from Crypto.Util import asn1
from M2Crypto import m2
import sha
# the certificate
cert = """subject=/C=DE/O=SAP Trust Community/OU=SAP Web AS/OU=I0020154766/CN=RE2
issuer=/C=DE/O=SAP Trust Community/OU=SAP Web AS/OU=I0020154766/CN=RE2
-----BEGIN CERTIFICATE-----
MIICMDCCAe8CAQAwCQYHKoZIzjgEAzBkMQswCQYDVQQGEwJERTEcMBoGA1UEChMT
U0FQIFRydXN0IENvbW11bml0eTETMBEGA1UECxMKU0FQIFdlYiBBUzEUMBIGA1UE
CxMLSTAwMjAxNTQ3NjYxDDAKBgNVBAMTA1JFMjAeFw05NzEwMDEwMDAwMDBaFw0z
ODAxMDEwMDAwMDBaMGQxCzAJBgNVBAYTAkRFMRwwGgYDVQQKExNTQVAgVHJ1c3Qg
Q29tbXVuaXR5MRMwEQYDVQQLEwpTQVAgV2ViIEFTMRQwEgYDVQQLEwtJMDAyMDE1
NDc2NjEMMAoGA1UEAxMDUkUyMIHyMIGpBgcqhkjOOAQBMIGdAkEA//8x1Bqn4a00
FKr9CTwPPskxy0yrx7iU6T4vza4wW93Mo2d/IYTZNAxFqhrm+fIUrEp5fxIpYRmJ
rKL2qRCUmQIVANrcsXlFvrXH455gM69vKZebhQZfAkEAmYzXTzHYwvqKEM46FvQX
yC5O+JInwgk7Dac7gqGAkkhCS1aII4Vkc9kIEx3GFLD2mx4+yJuMQ8pQ4wz4FkfB
JANEAAJBAI1em/0owxMTEP+akz56BovQ7Q6LiqUmVLLxJcjDozjI+5z6IrAPtub2
veLXPdghDHcHB5jHKoqT4JHpqRc+uhIwCQYHKoZIzjgEAwMwADAtAhRm2jqiMWL+
26mA7HdKfZdkawMuYQIVAMekXdAT4wbyrb5/yFtuIPjCBfpr
-----END CERTIFICATE-----
"""
f = open('sapcert.pem', 'w')
f.write(cert)
f.close()
# now you can see it content with openssl
# openssl x509 -in sapcert.pem -inform pem -text
# this is the signedMessage
secKey = "MIIBSwYJKoZIhvcNAQcCoIIBPDCCATgCAQExCzAJBgUrDgMCGgUAMAsGCSqGSIb3DQEHATGCARcwggETAgEBMGkwZDELMAkGA1UEBhMCREUxHDAaBgNVBAoTE1NBUCBUcnVzdCBDb21tdW5pdHkxEzARBgNVBAsTClNBUCBXZWIgQVMxFDASBgNVBAsTC0kwMDIwMTU0NzY2MQwwCgYDVQQDEwNSRTICAQAwCQYFKw4DAhoFAKBdMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTExMDUyNjE1MzAyNVowIwYJKoZIhvcNAQkEMRYEFPelg4iVtaKORpuFxUvgo23Du7%2BtMAkGByqGSM44BAMELjAsAhQ46oCNmzZArb5yOFSYGY0hWu8dZwIUT35hPccJ6B9HIsOE0u8LwYZaFNk%3D"
secKey = urllib.unquote(secKey)
secKey64 = base64.b64decode(secKey)
# now you can save it as a DER encoded file
f = open('seckey.der', 'wb')
f.write(secKey64)
f.close()
# you can pass it to openssl to see the the content
# openssl asn1parse -in seckey.der -inform der
# here is the sha1 encoded messagedigest I had to verify
hashstr = "ZS4DDB9616BA031C40E1008003AC100097dCN%3DRE2,OU%3DI0020154766,OU%3DSAPWebAS,O%3DSAPTrustCommunity,C%3DDE20110526173025"
osha1=M2Crypto.EVP.MessageDigest('sha1')
osha1.update(hashstr)
sha1_md = osha1.digest()
print sha1_md.encode('hex')
# now i build a DSA key with the params found in the certificate
pub="8d5e9bfd28c3131310ff9a933e7a068bd0ed0e8b8aa52654b2f125c8c3a338c8fb9cfa22b00fb6e6f6bde2d73dd8210c77070798c72a8a93e091e9a9173eba12"
p="ffff31d41aa7e1ad3414aafd093c0f3ec931cb4cabc7b894e93e2fcdae305bddcca3677f2184d9340c45aa1ae6f9f214ac4a797f1229611989aca2f6a9109499"
q="dadcb17945beb5c7e39e6033af6f29979b85065f"
g="998cd74f31d8c2fa8a10ce3a16f417c82e4ef89227c2093b0da73b82a1809248424b568823856473d908131dc614b0f69b1e3ec89b8c43ca50e30cf81647c124"
pub1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(pub))
p1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(p))
q1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(q))
g1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(g))
# this function is available after patching und compiling M2Crypto
# https://bugzilla.osafoundation.org/attachment.cgi?id=5700
dsa1 = M2Crypto.DSA.pub_key_from_params(p1, q1, g1, pub1)
print dsa1.check_key()
# this seems to be the signature-values r and s in seckey.der
asn_hex = "302C021438EA808D9B3640ADBE72385498198D215AEF1D6702144F7E613DC709E81F4722C384D2EF0BC1865A14D9"
r = asn_hex[8:48]
s = asn_hex[52:]
r1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(r))
s1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(s))
# but this fails
v = dsa1.verify(sha1_md, r1, s1)
print v
# this too
sk = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.bin_to_bn(secKey64))
v = dsa1.verify(sk, r1, s1)
print v
有人知道如何进行正确的dsawithsha1签名验证吗?请帮忙！ 最好的祝福， 法尔科
在示例代码中命名为 在您的情况下，原始数据的消息摘要包含在message-digest属性中，因此您需要首先将计算与该属性的每个字节的值字节进行比较. 如果这些相等，那么您将从SignerInfo结构的适当字段中提取签名值.最后，将根据SignerInfo签名属性的原始编码来计算作为DSA签名验证的其他输入的SHA-1消息摘要.我不确定M2Crypto是否具有对SignedData的内置支持(通常仍称为PKCS#7)，但是我想 pyOpenSSL 应该支持它，因此如果M2Crypto导致您陷入僵局，则可以尝试一下. -
I'm trying to verify a signed message using a x509 certificate holding a dsa public key.
The x509 certificate was provided by an SAP System in PKCS7 encoding and after converting in PEM with openssl I'm able to read the contents (openssl x509 -in sapcert.pem -inform pem -text)
It holds a public key in dsaEncryption, showing me the DSA parameters y(pub), p, q and g. Because I did not found a DSA implementation in M2Crypto x509 class, i tried to build the DSA public key by myself. Therefor I patched MyCrypto, (see: How do I create a M2Crypto DSA object given parameters and key values?), compilied it and got a new function DSA.pub_key_from_params(p,q,g,y) to build my DSA public-key using the parameters found in the certificate.
Until this point everything works fine. (The unittest although ran without errors). in the second step I recieve the signedMessage (named seckey) as an URL parameter and after decoding it (base64) I got an proper DER string I'm able to read with openssl (openssl ans1parse -in seckey -inform der).
In the output from openssl I can see the signed messageDigest, which is exactly the SHA1 encoded messagedigest I try to verify (so I can be sure the signedMessage was provided properly). Although I can see a dsaWithSHA1 signature string which seems to hold the r and s values needing for verify an dsa signed message (see: M2Crypto: verifying DSA signatures) At this point I stuck in my attempts to verify the signedMessage for a couple of days now and I hope there is a crytographic-expert out there who can help me. I tried and googled a lot, tried the pyCrypto lib instead, all without success. I tried to pass the SHA1 MessageDigest and the r and s values to the M2Crypto.DSA.verify function but due it fails I think I either had to pass the signedMessage or parts of it.
(in a Java forum I found some posts about verifying signedMessages provided by SAP and theres somewhat about calculating the signature over "the DER encoding
of the signed attributes." ?) Here's my sample code: Is there anybody who knows how to do a proper dsawithsha1 signature verification? Please help!
best Regards,
Falko What you named It contains two "signed attributes", signing-time and message-digest. In order to verify this as a signature you need to follow the rules of the RFC that apply when at least one signed attribute is present. In your case the message digest of the original data is contained in the message-digest attribute, so you would need to compare your computation with the attribute's value byte per byte first. If these are equal, then you'd extract the signature value from the appropriate field of the SignerInfo structure. Finally your SHA-1 message digest that serves as the other input to the DSA signature verification will be computed over the raw encoding of the signed attributes of the SignerInfo. I'm not sure if M2Crypto has built-in support for SignedData (it's still often referred to as PKCS#7), but I guess pyOpenSSL should support it, so you could give it a try if M2Crypto leads you to a dead end. 这篇关于无法针对python/m2crypto中的DSA公钥验证dsawithSha1签名的消息的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！seckey64的实际上是来自
# -*- coding: iso-8859-1 -*-
import M2Crypto
import urllib
import base64
from Crypto.Util import asn1
from M2Crypto import m2
import sha
# the certificate
cert = """subject=/C=DE/O=SAP Trust Community/OU=SAP Web AS/OU=I0020154766/CN=RE2
issuer=/C=DE/O=SAP Trust Community/OU=SAP Web AS/OU=I0020154766/CN=RE2
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
"""
f = open('sapcert.pem', 'w')
f.write(cert)
f.close()
# now you can see it content with openssl
# openssl x509 -in sapcert.pem -inform pem -text
# this is the signedMessage
secKey = "MIIBSwYJKoZIhvcNAQcCoIIBPDCCATgCAQExCzAJBgUrDgMCGgUAMAsGCSqGSIb3DQEHATGCARcwggETAgEBMGkwZDELMAkGA1UEBhMCREUxHDAaBgNVBAoTE1NBUCBUcnVzdCBDb21tdW5pdHkxEzARBgNVBAsTClNBUCBXZWIgQVMxFDASBgNVBAsTC0kwMDIwMTU0NzY2MQwwCgYDVQQDEwNSRTICAQAwCQYFKw4DAhoFAKBdMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTExMDUyNjE1MzAyNVowIwYJKoZIhvcNAQkEMRYEFPelg4iVtaKORpuFxUvgo23Du7%2BtMAkGByqGSM44BAMELjAsAhQ46oCNmzZArb5yOFSYGY0hWu8dZwIUT35hPccJ6B9HIsOE0u8LwYZaFNk%3D"
secKey = urllib.unquote(secKey)
secKey64 = base64.b64decode(secKey)
# now you can save it as a DER encoded file
f = open('seckey.der', 'wb')
f.write(secKey64)
f.close()
# you can pass it to openssl to see the the content
# openssl asn1parse -in seckey.der -inform der
# here is the sha1 encoded messagedigest I had to verify
hashstr = "ZS4DDB9616BA031C40E1008003AC100097dCN%3DRE2,OU%3DI0020154766,OU%3DSAPWebAS,O%3DSAPTrustCommunity,C%3DDE20110526173025"
osha1=M2Crypto.EVP.MessageDigest('sha1')
osha1.update(hashstr)
sha1_md = osha1.digest()
print sha1_md.encode('hex')
# now i build a DSA key with the params found in the certificate
pub="8d5e9bfd28c3131310ff9a933e7a068bd0ed0e8b8aa52654b2f125c8c3a338c8fb9cfa22b00fb6e6f6bde2d73dd8210c77070798c72a8a93e091e9a9173eba12"
p="ffff31d41aa7e1ad3414aafd093c0f3ec931cb4cabc7b894e93e2fcdae305bddcca3677f2184d9340c45aa1ae6f9f214ac4a797f1229611989aca2f6a9109499"
q="dadcb17945beb5c7e39e6033af6f29979b85065f"
g="998cd74f31d8c2fa8a10ce3a16f417c82e4ef89227c2093b0da73b82a1809248424b568823856473d908131dc614b0f69b1e3ec89b8c43ca50e30cf81647c124"
pub1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(pub))
p1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(p))
q1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(q))
g1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(g))
# this function is available after patching und compiling M2Crypto
# https://bugzilla.osafoundation.org/attachment.cgi?id=5700
dsa1 = M2Crypto.DSA.pub_key_from_params(p1, q1, g1, pub1)
print dsa1.check_key()
# this seems to be the signature-values r and s in seckey.der
asn_hex = "302C021438EA808D9B3640ADBE72385498198D215AEF1D6702144F7E613DC709E81F4722C384D2EF0BC1865A14D9"
r = asn_hex[8:48]
s = asn_hex[52:]
r1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(r))
s1 = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.hex_to_bn(s))
# but this fails
v = dsa1.verify(sha1_md, r1, s1)
print v
# this too
sk = M2Crypto.m2.bn_to_mpi(M2Crypto.m2.bin_to_bn(secKey64))
v = dsa1.verify(sk, r1, s1)
print v
seckey64 in your sample code is actually a SignedData structure from CMS.
