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Glossary
DES / 3DES
Private Key, Public
key; Certification
(X.509)
98 von 105
The symmetrical encryption algorithm (# symmetrical encryption)
DES, originally developed by IBM and checked by the NSA, was
determined in 1977 by the American National Bureau of Standards,
the predecessor of today's National Institute of Standards and
Technology (NIST), as the standard for American government
institutions.
As this was the first standardized encryption algorithm of all, it
quickly established itself in industry and hence outside the USA.
DES works with a key length of 56 bits, which is no longer
considered secure due to the increase in computing power since
1977.
3DES is a variant of DES. It works with 3-times larger keys, i.e. 168
bits long. It is still considered secure today and is, among other
things, also part of the IPsec standard.
In asymmetrical encryption algorithms 2 keys are used: a Private
Key and a Public Key. The public key serves to encrypt data and
the private key to decrypt them.
The public key is provided by the future recipient of the data to
those who will send the data to him in encrypted form. The private
key is possessed only by the recipient and serves to decrypt the
received data.
Certification:
So that the user of the public key (for encryption) can be certain
that the public key conveyed to him really does come from the
entity that is to receive the data to be sent, certification can be
used: the verification of the authenticity of the public key and the
consequent link between the identity of the sender and his key is
performed by a Certification Authority or CA. This is done according
to the rules of the CA, for example by the sender being required to
appear in person. Following successful inspection the CA signed
the sender's public key with its (digital) signature. A certificate is
created.
An X.509 certificate makes a connection between an identity in the
form of an 'X.500 Distinguished Name' (DN) and a public key. This
connection is authenticated by the digital signature of an X.509
Certification Authority (CA). The signature - an encryption with the
signature key - can be checked with the private key issued by the
CA to the certificate holder.
SINAUT MD740-1
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