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

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ECDH-ECDSA Combination [migrated]

I am doing research on cryptography primitives at a basic level and I faced a question on encryption methods. I understood that ECDH is an approach to for secure key exchange between two parties ...
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How can I use ECC 163?

I will be working with a Sentinel dongle. In the 3rd tab, it says it supports ECC 163. I will be both encrypting and decrypting with the dongle, as well as on a server. The server uses PHP but I can ...
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38 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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67 views

BLS signature java implementation needed (if possible, along with some example code)

I need to sign a string with the shortest digest possible using regular certificate like X.509. As far as I understand, I will have to transform the string to the sequence of bytes, then sign. After ...
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Presentation format for curve25519 private key?

I'm having trouble finding a presentation format for curve25519 private key. Does any know how its been defined? Will it follow PKCS #8? Related, the OID for the curve is being finalized at ...
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Read back in “human readable” text from openssl ec -pubout

I'm looking to understand how/if the output of the openssl ec -in pub.pem -pubin -pubout -text -noout command can be used to reconstitute the public key. I'm hoping it can be a symmetrical operation? ...
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29 views

Smartcard authentification: encrypt/decrypt or ECDSA?

I'm implementing a simple door access control with smart keyfobs. At the moment I send a 32 byte message to the keyfob which it signs with ECDSA and I verify the authenticity with the public key. ...
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77 views

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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Curve25519xsalsa20poly1305 key derivation

I'm working on batch-encryption of files, for a small project of mine. The files are stored encrypted on a removable drive, and the keys are stored on a trustful server. For enhanced safety, I'd like ...
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80 views

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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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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1k views

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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540 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
95 views

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
88 views

How to encrypt with ECDSA?

Suppose there's a transaction in the blockchain in which a given address transfers bitcoins to whoever. I need to encrypt a message so only the owner of that address will read it. I have his public ...
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1answer
89 views

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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1answer
49 views

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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2answers
83 views

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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233 views

RSA BSAFE Crypto-J JCE provider - “Server Hello” returns unassigned Named Curve

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). when I use any elliptic curve based key exchange mechanism the handshake fails ...
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3answers
379 views

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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1answer
186 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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100 views

Confused about RFC 4492: difference between “ECDH-capable public key” and “ECDSA-capable public key”

As per section 5.3 of RFC 4492, I'm confused with the following table: Key Exchange Algorithm Server Certificate Type ---------------------- ----------------------- ...
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443 views

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 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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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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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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161 views

What's RSA and ECC's role in TLS 1.2? [duplicate]

I'm trying to figure out what is RSA and ECC used for in TLS 1.2 cipher suites. Let's take TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 for example, communication between server and client would look ...
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271 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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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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66 views

Alternative to ECC for mobile security

I asked a question a couple of months back, which led me to ECC. The following question is in continuation: Current Setup: I've two devices A and B which need to interact with each other securely ...
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127 views

What does the EC Private key version field mean?

I have read the question Converting ECC Private key to PKCS#1 format. And I understood that the value of the version field of the traditional EC private key is 01. We can use the command openssl ...
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61 views

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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2k views

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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366 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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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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466 views

openSSL selects ECDH-RSA instead of ECDH-ECDSA

I am trying to do a secure connection with openSSL between a client and a server that I wrote. When I try to select the cipher suite to use, I do SSL_CTX_set_cipher_list(ctx, ...
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52 views

length of a session key in EC?

In elliptic curve cryptography what should be the length of session key? Is there a specific metric to choose one, or are they randomly generated? I was studying one paper about defence against a ...
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481 views

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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5k views

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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137 views

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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195 views

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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3k views

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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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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How to generate ECC (160 bits) Keys with OpenSSL? [closed]

I have this problem: I want generate RSA Keys at 1024 bits with OpenSSL. I do this with this commands: For generate RSA Key at 1024 bits: openssl genrsa -out rsa.key 1024 For view the content of ...
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1k views

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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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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2k views

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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643 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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2k views

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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4answers
283 views

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 ...