An ITU-T standard for privilege management infrastructure (PMI) and a public key infrastructure (PKI).

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How TLS certificate chain is verified

Assume the verification of a TLS certificate chain. Suppose the chain has certificates A-B-C-D where D is the root certificate and A is signed by B, B by C, C by D. Suppose the intermediate ...
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24 views

Why are there leading 0x00 bytes in the subjectPublicKey field of a DER X.509 cert?

For a simple example, I'm using a 512-bit RSA cert to illustrate my question. The cert can be found in both DER and PEM form here. I've been going through the certificate using this ASN.1 decoder (the ...
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1answer
33 views

Generate Subject Key Identifier by hand using openssl command sequence

When creating a signed certificate I get the lines inside the certificate that identify the keys used: X509v3 extensions: X509v3 Subject Key Identifier: D8:D7:3F:99:CC:D7:20:AF:62:31:...
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45 views

Firefox refuses to use X509 certificate, complaining “Cound not verify this certificate for unknown reasons”

I stumbled upon this question and answer. I have the same problem as the OP, and am sorry to report that the proposed answer does not resolve it. Certificate in question has been verified by OpenSSL-1....
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0answers
30 views

Generating a cert for use to digitally sign an email

I am having some issues generating certs, past a certain point. So far, I have done the following to generate a CSR, and have obtained an intermediate cert from the provider, and another CRT file. I ...
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1answer
111 views

Why would I need to use the PRIVATE key to verify a file signature?

I use JavaScript to open CAPICOM store to choose certificate. After that I export selected certificate, public key and private key of that certificate and put them in three hidden fields. var ...
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2answers
76 views

Trusting the “subject” of an x509 certificate

A bit of background. Our organization is working on a document format that will be ingested by our software. We're using the CMS format to verify the integrity (by validating the signature). The CMS ...
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2answers
76 views

What advantage would someone gain by installing my root certificate?

The answer to this is probably simple, but it eludes me. Here's the scenario: At the moment, I have a server with a certificate issued to it using HTTPS that a customer POSTs responses to after ...
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3answers
59 views

Is it possible to prove that a TLS server key has changed?

I know of a site that is currently using SSLv2 and I'm refusing to connect to them until they Disable SSLv2 Re-key their servers I'm insisting on #2 because due to DROWN, servers running SSLv2 ...
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1answer
34 views

Extract X509 client certificates from TCPdump files

I have the following question: assuming I have a TCPDump file containing a number of HTTPS connections using TLS mutual authentication, is there a way to extract all client certificates sent to the ...
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1answer
114 views

Java / Android Client-Server application. Digital certificates and CAs

I'm currently developing an application for Android that will allow users to back up their data on a server, which I am also developing in Java. I've pretty much completed the development of the ...
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2answers
271 views

Use openssl to individually verify components of a certificate chain

This is related to another question, How to verify a signature of one entity by another using OpenSSL CLI? I used openssl s_client -showcerts -connect www.google.com:443 to collect three certificates ...
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1answer
94 views

How to verify a signature of one entity by another using OpenSSL CLI?

I'm teaching a class about certificate chains, so I download the chain from www.google.com which has 4 certs. I want to demonstrate how the dependencies work from issuer to subject by showing that ...
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2answers
148 views

Can a CN-only certificate bypass a name constraint if the CA goes rogue?

I am trying to cross-certify an internal issuer certificate, adding a name constraint for our domain. However, it seems that an attacker could bypass this protection by putting the desired host name ...
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0answers
29 views

Finding the EMSA-PKCS1-v1_5 DigestAlgorithm field in the x509 certificate

From the RFC - https://www.ietf.org/rfc/rfc3447.txt A.2.4 RSASSA-PKCS1-v1_5 For each OID, the parameters field associated with this OID in a value of type AlgorithmIdentifier shall have a value ...
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2answers
357 views

Why don't banks sign their email using S/MIME?

If email sent by my bank included S/MIME signatures that my mail client can verify, then I would have the assurance that the mail was not tampered with or sent by some malicious third-party. Most ...
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1answer
117 views

Why is the Signature Algorithm listed twice in an x509 Certificate?

Section 4.1 of RFC 5280 defines the contents of an x509 Certificate. Specifically, two fields are listed (signatureAlgorithm and signature) and defined to contain the same information: ...
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2answers
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what is the different between X.509 certificate and 2-way SSL? or both are same? [duplicate]

Can anyone clarify what is the difference between an X509 certificate and two-way SSL? or both are same?
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1answer
113 views

SSL/TLS: Policy Constraints vs. Basic Constraints

Could someone please explain the difference between Policy Constraints and Basic Constraints? It appears to me that they are either redundant, or two names for the same thing. I would love some ...
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1answer
51 views

Can attribute certificates be used with TLS / HTTPS?

Can attribute certificates (also known as authorization certificates) be used with HTTPS? For instance, can a HTTPS server supply an attribute certificate in addition to its ordinary SSL certificate? ...
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1answer
251 views

X.509 Certificate Signature Collision Vulnerability

Customer complained that during security scan performed on our application the following was raised: 172.22.0.19 - xxxxx - IETF X.509 Certificate Signature Collision Vulnerability - https/tcp/172.22....
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1answer
106 views

Are fields of a root CA certificate checked?

During SSL server validation, it seems that the only fields of X509 certificates found in trust stores that are actually used are the "Common Name" and the "Public Key". I'm not talking about any ...
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2answers
298 views

Creating root CA to issue certificates programatically

I have to generate a self signed root CA and use it to issue to certificates programatically. I am new to security and certificates and I think I am missing some pieces required to make the whole ...
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25 views

SCEP CertRep SUCCESS: how many certs are in the response?

I am working on an SCEP implementation (both requester and authority). The project uses JScep as a library. During the communication for a PKCSReq the client receives a CertRep SUCCESS. The draft ...
2
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1answer
138 views

signature and padding

I use JcaContentSignerBuilder to sign a self-signed certificate but I don't know what the default padding is. My requirement is that I must NOT use PKCS#1.5 padding. The code I use is below - can ...
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2answers
66 views

Include multiple pub keys in a x509v3-cert

Is it possible to include multiple public keys and the issuer's public key in one x509v3-certificate?
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1answer
79 views

CRL verification with renewed CA

I would like to understand how is CRL verified and therefore certificate of end entity verified when there is a new certificate and keys of issuing CA renewed. Suppose I have the following setup: ...
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1answer
27 views

Validating a certificate chain without x509v3 Subject Key IDs

I work for a hosting company and we do not currently offer certificate signing services, so we have to accept 3rd-party certificates from non-technical clients. I am trying to build a tool to verify ...
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0answers
44 views

Verify request using the X509 certificate [closed]

I have a SOAP server. The soap request that is receiving at the server has ws security headers. Following are the main nodes of the request XML. BinarySecurityToken (X509PKIPathv1 certificate) ...
3
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1answer
380 views

How can I use my HSM to turn a CSR into a certificate?

I create a CSR using OpenSSL, so I have public and private keys. Now I want to sign this CSR and convert it into an X.509 certificate. The only problem is, my signer is a custom HSM. I can send bytes ...
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1answer
119 views

x.690 universal class tags implementation reference

Can anyone with enough knowledge of X.690 tell me where can I find the official reference implementation for the universal class tags for X.690. (For example: For TLS we can reference RFC 5246.) When ...
2
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1answer
148 views

Attribute Certificates and Access Management

I recently came across Attribute Certificates (RFC 5755), which can be used as a means for authorisation. I like the idea but I have spent a lot of time searching for information how this works in a ...
2
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1answer
736 views

Difference between certificates with “extension fields” and “Non Repudiation” usage

For example we have two certificate pairs: First pair: Server cert with "Non Repudiation" (sometimes called Content Commitment) usage, Client cert without any "extension fields". Second pair: ...
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94 views

Certificate policies extension in Root CA and Issuing CA

I am building new CA chain and PKI and I actually don't fully understand how I should include certificate policies (CP) and certificate practice statements (CPS) as extensions and how to work with it ...
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1answer
106 views

Certificate expiry validation - in what stage?

I'm implementing certificate expiry validation for a client. I'm not sure about the following. Is there a standard/popular implementation regarding the order of validation- Check if the ...
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2answers
248 views

Are X.509 nameConstraints on certificates supported on OS X?

I have the following "chain" of certificates on a test machine right now: A self-signed CA cert, in my Keychain and trusted & trusted by Firefox. A CA cert with with the following, X509v3 Name ...
5
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1answer
122 views

OpenSSL Certificate Expiry

I'm trying to use OpenSSL to verify that an SSL certificate is still valid, but I keep getting strange results. The example site that I'm testing with (expired.badssl.com) has an expired SSL ...
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1answer
274 views

Should I use the certificate serial number or the subject key identifier to look up public key?

I'm designing an API authentication mechanism similar to the one AWS use. As part of that, I need to look up which public key belongs to which user to verify. The public keys come from x509 ...
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0answers
89 views

Distribution of a public key with a dotnet client application?

I have a pretty good understanding of X509 cryptography etc, from my career in the smart card industry. So I know that the card scheme (e.g. Visa, MasterCard) is the highest level of trust - they sign ...
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2answers
707 views

How to identify which root CA does the client certificate use?

How can we identify which root CA client used when there are multiple root CAs on the server? We can compare the public keys of the client certificate and the root certificate but if we have many ...
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3answers
131 views

do serial numbers for x509 certs need to be sequential or can they be timestamp's?

Serial numbers need to be unique for X.509 certs but do they need to be sequential or is making them equal to the time that the cert was generated sufficient?
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2answers
554 views

OpenSSL x509: Is there an order in subjectName fields?

Is there an order to respect in subjectName field when creating a x509 certificate with OpenSSL command? In other words, what are all possibilities of displaying subjectName of x509 certificate in ...
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0answers
156 views

How to generate “CRL numbers” for X.509 CRL

(Context: I'm working a process to publish a CRL periodically -- eg once every day.) With standard X.509 certificates, "serial numbers" are required to be positive integers, but they do not need to ...
2
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1answer
85 views

is x509 certificate signed by ca valid?

I've got certificate 'sample cert' which is valid to '2015-12-31' but it was signed by root CA certificate. But when it was signing CA cert was valid to 2015-06-30'. So my question is, is today (2015-...
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1answer
824 views

Create PKCS7 signature, signed by X.509 CA, which embeds an XML file

I have to create a PKCS7 signature file signed by an X.509 certificate and I have to embed an XML file within. How to do that with OpenSSL or any other tool?
4
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1answer
312 views

Difference between public key and private key validity period

In the section about certificate extensions, the ITU-T X.509 recommendation writes: The private key corresponding to a certified public key is typically used over a different period from the ...
6
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2answers
329 views

Custom data in SSL certificate

I am looking for a way to add extra, custom data in a SSL server certificate issued by a standard CA. Is this possible? I want to get a SSL server certificate issued by a standard CA, so that it'll ...
2
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0answers
44 views

Potential hazards for reusing an X.509 private key for multiple services?

One thing I've been thinking about for a while is using a X.509 private key stored in a hardware security device (think YubiKey et al) on a one-per-machine basis. Theoretically, it should be possible ...
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1answer
270 views

How to extend x509 certificate validity

I have two x509certificate, and now they are expired. What I would do is to extend the validity date of these certificates (I don't want t creat new one). Can I do this with openssl or other tools ?
3
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1answer
88 views

How common are UTF8 strings in X509

In theory, names in X509 certs are defined as: CHOICE { teletexString TeletexString (SIZE (1..ub-state-name)), printableString PrintableString (SIZE (1..ub-state-name)), universalString ...