Lantronix EDS8PS Podręcznik Użytkownika Pobierz pdf (Strona 145)

15: Security in Detail

EDS User Guide 145

EDS currently supports the following list of cipher suites:

Certificate Key exchange Encryption Hash

DSA DHE 3DES SHA1

RSA RSA 128 bits AES SHA1

RSA RSA Triple DES SHA1

RSA RSA 128 bits RC4 MD5

RSA RSA 128 bits RC4 SHA1

RSA 1024 bits RSA 56 bits RC4 MD5

RSA 1024 bits RSA 56 bits RC4 SHA1

RSA 1024 bits RSA 40 bits RC4 MD5

Whichever side is acting as server decides which cipher suite to use for a connection.

It is usually the strongest common denominator of the cipher suite lists supported by

both sides.

Certificates

The goal of a certificate is to authenticate its sender. It is like a paper document that

contains personal identification information and is signed by an authority, for example

a notary or government agency.

Security Certificate Principles

To sign other certificates, the authority uses a private key.

 The published authority certificate contains the matching public key that

allows another to verify the signature but not recreate it.

 The authority’s certificate can be signed by itself, resulting in a self-signed or

trusted-root certificate, or by another (higher) authority, resulting in an

intermediate authority certificate.

 You can build up a chain of intermediate authority certificates, and the last

certification will always be a trusted-root certificate.

An authority that signs other’s certificates is also called a Certificate Authority (CA).

 The last in line is then the root-CA.

 VeriSign is a famous example of such a root-CA. Its certificate is often built

into web browsers to allow verifying the identity of website servers, which

need to have certificates signed by VeriSign or another public CA.

Since obtaining a certificate signed by a CA that is managed by another company

can be expensive, it is possible to become your own CA. Tools exist to generate self-

signed CA certificates or to sign other certificates.

 A certificate before it is signed is known as a certificate request, which only

contains the identifying information. Signing it makes it a certificate.

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Lantronix EDS8PS Podręcznik Użytkownika Strona 145