ECC stands for Elliptic Curve Cryptography. Elliptic curves are a mathematical structure which allow to define cryptographic operations on them.

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What is ECDHE-RSA?

What is the difference between ECDHE-RSA and DHE-RSA? I know that DHE-RSA is (in one sentence) Diffie Hellman signed using RSA keys. Where DH is used for forward secrecy and RSA guards against MITM, ...
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Which elliptic curve should I use?

I am currently renewing an SSL certificate, and I was considering switching to elliptic curves. Per Bernstein and Lange, I know that some curves should not be used but I'm having difficulties ...
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Can ECC be used without infringing on patents?

Can ECC (Elliptic Curve Cryptography) be safely used without infringing on Certicom's patents? I would like to make use of ECC in an embedded system to establish a secure channel. But, I am concerned ...
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ECC in (Open)PGP

How is with the support for ECC (Elliptic Curve Cryptography) in (Open)PGP so far? It seems that GnuPG (The GNU Privacy Guard) doesn't have an official implementation - but I did find the gnupg-ecc ...
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Is it bad that my ed25519 key is so short compared to a RSA key?

I recently generated a new SSH key in the ed25519 format. The public key is only 69 bytes long while my old RSA key is 373 bytes. From my perception ed25519 is the more recent and secure format. So ...
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What elliptic curves are supported by browsers?

Wireshark'ed Firefox 3 request. Their names are nowhere documented. Elliptic curve: secp256r1 (0x0017) Elliptic curve: secp384r1 (0x0018) Elliptic curve: secp521r1 (0x0019) What are the supported ...
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Can custom elliptic curves be used in common TLS implementations?

Recent developments have cast some doubt on the elliptic curves specified by NIST and used in many standards like TLS (for signatures with ECDSA and key agreement with ECDHE). It seems like the ...
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Strength and length of Symmetric vs Asymmetric keys [duplicate]

There are many questions surrounding the differences between symmetric and asymmetric encryption keys. I think I've read them all at this point. But I'm still left wondering: Why does a "secure" ...
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Is ECDH for SEC P-384 and P-521 broken in Windows 10 / Windows Server 2016 TP3?

UPDATE: Proof of concept code here, console output shown below and all involved certificates are here. Just noticed that ECDiffieHellmanCng.DeriveKeyMaterial(...) behaves differently on Windows 8.1 ...
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ECC based Client Certificate import in Chrome/Mozilla in windows

I have deployed a PKI server and successfully able to generate the ECC based user or client certificates. but non of the web browser support ECC as public key. I have tried different tools and also ...
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Why is ECC more vulnerable than RSA in a post-quantum world?

Forgive me if this should be in the crypto sub, but sometimes the answers there are very mathematical and I would rather have an answer which is a bit lighter on the math but still strong on the tech ...
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Generating ECDSA certificate and private key in one step

Similar to how it can be easily done for RSA: openssl req -x509 -nodes -newkey rsa:2048 -rand /dev/urandom -keyout example.key -out example.crt -days 365 I'd like to generate a ECDSA cert/key in ...
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SSH Key: Ed25519 vs RSA

A lot of people recommend using Ed25519 instead of RSA keys for SSH. The introduction page of Ed25519 (http://ed25519.cr.yp.to/) says: [..] breaking it has similar difficulty to breaking [..] RSA ...
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227 views

ECDH BouncyCastle KeyAgreement length

I am attempting to obtain a shared secret using BouncyCastle's ECDH methods in C#, however I am receiving a shared key which is much shorter than the 48 bytes I expect it to be. I have a trusted ...
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701 views

Why was ECMVQ dropped from NSA Suite B?

I've found two mentions on Wikipedia that Elliptic Curve Menezes–Qu–Vanstone (ECMVQ) was dropped from NSA's Suite B however they seem to imply different reasons. One mention is preceded by talk of how ...
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openssl ECDHE-RSA… cipher suite selected while using RSA server cert and ECDSA client cert

The scene: s_server using RSA certificate. s_client using ECC-ECDSA certificate. Client authentication is required (option -Verify set on s_server) Cipher-suite selected after handshake is ...
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Why is Elliptic Curve Cryptography not used much outside of government? [closed]

It seems that Elliptic Curve Cryptography, being required by the US government, is not being used outside of the government. Why is this? And why does the government support it's use for government? ...
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RFC 6637: Algorithm-Specific Fields for ECDH

I am trying to integrate RFC 6637 into Bouncy Castle C# which is more challenging as initially thought because both private key and public key have to be present to calculate the share secret: that ...
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Using Different Algorithms in Single PKI

Assume the following Public Key Infrastructure: |Root CA (RSA) |-Sub CA (RSA) |-Sub CA (ECC) Is there any rational that explains why this would not be an acceptable implementation? Is the ...
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Converting ECC Private key to PKCS#1 format

Is there any way to convert an ECC private key to RSA PKCS#1 format? I have tried converting it to PKCS#8 first using OpenSSL: openssl pkcs8 -topk8 -nocrypt -in EC_key.pem -out pkcs8_key.pem This ...
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Using Elliptic Curve Cryptography

I am wondering if ECC could be used the way that the data is encrypted with the public key instead of the random generated key. Is there any advantage doing that comparing to the "traditional" way of ...
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ECC and RSA 10K stronger claim

There are a lot of websites where it is claimed something akin to this but no explanation on the basis. "ECC key size of 256 bits is equivalent to a 3072-bit RSA key and 10,000 times stronger than a ...
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Is it secure to create a Bitcoin address from a private key generated by Rand() instead of cryptographic elliptic curve

I am writing a C++ application that creates a Bitcoin address. I am having a hard time installing openssl for windows and making it work for visual studio. So, I am asking myself, if I create a ...
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Is the limited elliptic curve support in rhel/centos/redhat openssl robust enough?

Redhat finally gave in after insisting for years that elliptic curves had patents and disabling them, recently enabling a whopping three algorithms: CentOS 6.5 openssl ecparam -list_curves ...
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LibTomCrypt weird ECC Keys

I recently started working with the LibTomCrypt Library because it claimed to be a well documented C Library to get started with Elliptic Curve Cryptography. In my first little program I created an ...
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187 views

Using ECC for PGP-Master Key in combination with Yubikey

I acquired a Yubikey Neo last month. Now I want to use the Smart-Card functionality for PGP. I followed the official guides on the Yubico Website tested it with 2048 RSA Keys and it worked fine. But ...
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1answer
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How can you check if a private key and certificate match in OpenSSL with ECDSA?

I know how to do this with RSA keys (see this article: Determine if private key belongs to certificate?) however I do not know how to do this for ECDSA certificate / key pairs. With RSA keys, the ...
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1answer
648 views

How does signing work with Elliptic Curve Crypto?

So I have read up and have a decent understanding of how the crypto works with Elliptic Curve Cryptography. I also think I have an understanding of how signing works with things like Elliptic Curve ...
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1answer
135 views

How do I find a PKI smart card reader/writer for development (Microsoft .NET)

I would like to learn how to develop software leveraging PKI smart cards. Ideally, I would use Microsoft Base Smart Card CSP, but I really just need the ability to store symmetric and asymmetric keys ...
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369 views

More secure curve than Curve25519

As far as I know, Curve25519 offers "only" a security level equal to an 128bit symmetric cipher. I'd like to know if there are new (not NIST) curves, which provide a security-level comparable to a ...
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1answer
336 views

What is the optimal result for the elliptic curve patent issue?

I saw an article this morning, discussing the fact that RSA and DH may be significantly less secure in the upcoming five years. Although the chance that this will materialize is small, I immediately ...
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Are there theoretical attacks against ECC Digital Signatures?

I was asked to do a research about attacks on various digital signature schemes. There is one thing that bothers me for which I could not find a direct answer. For digital signatures that are based ...
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39 views

DNSCrypt-proxy: This certificate looks valid

I have just installed dnscrypt-proxy and dnsmasq with DNSSEC but I get a strange message in the logfile from dnscrypt-proxy. [INFO] + DNS Security Extensions are supported [INFO] - [dnscrypt.eu-dk] ...
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Are the elliptical curves in ECDHE and ECDSA the same?

ECDHE is quite widely used and recommend. And it works with elliptical keys and provides forward secrecy. It's used for the key exchange. ECDSA is not widely used though, but it does also use ...
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Named curve value 0xffff in 'Server Hello' message

I'm using the RSA BSAFE Crypto-J 6.2 JCE provider in Java as SSL/TLS server (in FIPS 140 Compliant Mode for SunJSSE). It seems like at least Chrome and Firefox cannot establish a connection if ...
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HPKP and multiple SSL certificates

Some weeks ago, we enabled the HTTP Public Key Pinning header on our website. As per the specification, we included not only the SHA-256 fingerprint of our current RSA key, but also that of a backup ...
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Elliptic curve cryptography and key sharing

I want to know if it is possible in Elliptic curve cryptography to have 2 parties holding a part of the private key. The idea is to encrypt (for DSA) data with the 2 sub keys without any of the party ...
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Why don't more websites implement Perfect Forward Secrecy?

From what I understand, all it takes to enable PFS on a webserver is adding ephemeral cipher suites (ones that use DHE and ECDHE for the key exchange) to the list of cipher suites used in SSL/TLS ...
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How to Build Pre-Master Secret [duplicate]

I'm implementing a TLS-like system, which uses ECDHE-RSA-AE-GCM-SHA, and I've faced two interrogations. At the end of the handshake ( and before the ChangeCipherSpec message), both the client and the ...
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1answer
274 views

EC private key, RSA certificate. Is this realisable?

I was wondering if is it possible to generate EC private key: openssl ecparam -name sect571r1 -out ecparam.pem openssl ecparam -in ecparam.pem -genkey -noout -out eckey.pem then generate ...
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Using ECC like RSA, to Encrypt/Decrypt

Is there any way to implement encryption/decryption using ECC, like RSA does? For example, say some user wants to send a message containing a symmetric key to user X. Then, in RSA, I could just ...
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ECC Public Key length differs from bit representation

A 256 Bit ECC key-pair (256 Bit is supposed to be the length of the public key) generated with OpenSSL using this command from the manual: openssl ecparam -name secp256k1 -genkey -noout -out key.pem ...
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655 views

Advantages of using a Digital Signature Scheme (DSS) with Appendix instead of DSS giving Message Recovery

I've been looking at the EMV draft specification (pdf) for using Eliptic Curve Cryptography in payment cards instead of the currently used RSA. One thing I've noticed is that they've moved from using ...
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1answer
555 views

Why is secp521r1 no longer supported in Chrome, others?

Found a few issue threads, notably for Chrome (Chromium issue #478225), and the browser does appear to have dropped support for the secp521r1 curve (can test your browser using SSLLabs). There were ...
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1answer
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Specificity of ECDHE in a TLS handshake

It's just a short question, but I haven't find a clear answer yet... It's in the frame of a TLS-ECDHE handshake. Where does the specificity of the ECDHE, over the DHE, appears ? At which point do ...
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Finding ecc private key from plaintext and public key

I am working on a message authentication scheme using libsodium and ed25519. The messages range in size from 256bytes to 1k plus the 56byte signature. With a potential of 90,000 to 350,000 ...
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Securing ECC Private keys

What would be the equivalent to securing ECC private key similar to how RSA private keys are password protected through the PKCS#12 format? Another question I have is: how do I add ECC keys to a ...
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1answer
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Calculating D-Wave's integer factorization capabilties

D-Wave has teased the ability to perform integer factorization previously, but if you jump to ~10:00 in this presentation they actually appear to outline how they can perform integer factorization ...
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Is it possible to distinguish between a SHA256 hash and an ecc256 key?

If an attacker were just given 256 bits, and they were either a SHA256 hash or a 256 bit elliptic curve key, would they be able to tell which one it is? Just out of curiosity, would they be able to ...
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OpenSSL ECC named curve support

I tried searching online but can't seem to find whether or not OpenSSL support both NamedCurve.arbitrary_explicit_prime_curves and NamedCurve.arbitrary_explicit_char2_curves? As far as I can tell ...