Constraints-Specific Policy Module Reference
Chapter 12
Policies
483
SigningAlgorithmConstraints
The
SigningAlgorithmConstraints
plug-in module restricts the requested signing
algorithm to be one of the algorithms supported by CS: MD2 with RSA, MD5 with RSA,
and SHA-1 with RSA, if the Certificate Manager’s signing key is RSA and SHA-1 with
DSA, if the Certificate Manager’s signing key is DSA.
When a Certificate Manager digitally signs a message, it generates a compressed version of
the message called a message digest. Some of the algorithms used to produce this digest
include MD5 and SHA-1 (Secure Hash Algorithm).
•
MD5 generates a 128-bit message digest. Most existing software applications that
handle certificates only support MD5.
•
SHA-1 generates a 160-bit message digest. Some software applications do not yet
support the SHA-1 algorithm. For example, Netscape Navigator 3.0 (or higher) and
Enterprise Server 2.01 (or higher) support SHA-1; previous versions of these
applications do not support SHA-1.
You may apply this policy to end-entity certificate enrollment and renewal requests.
During installation, CS automatically creates an instance of the signing algorithm
constraints policy, named
SigningAlgRule
, that is enabled by default.
minSize
Specifies the minimum length, in bits, for the key (the length of the modulus in bits). The value
must be smaller than or equal to the one specified by the
maxSize
parameter. Permissible
values:
512
,
1024
,
2048
, or
4096
. You may also enter a custom key size that is between
512 and 4096 bits. The default value is
512
.
maxSize
Specifies the maximum length, in bits, for the key. Permissible values:
512
,
1024
,
2048
, or
4096
. You may also enter a custom key size that is between 512 and 4096 bits. The default
value is
2048
.
exponents
Limits the possible public exponent values. Use commas to separate different values.
Some exponents are more widely used than others. The following exponent values are
recommended for arithmetic and security reasons:
17
and
65537
. Of these two values,
65537
is preferred. (This setting is mainly an issue if you are using your own software for
generating key pairs. Key-generation programs in
Red Hat
clients and servers use
3
or
65537
.)
Permissible values: A combination of
3
,
7
,
17
, and
65537
, separated by commas. The default
value is
3,7,17,65537
.
Table 12-10
RSAKeyConstraints Configuration Parameters
(Continued)
Parameter
Description
Summary of Contents for CERTIFICATE 7.1 ADMINISTRATOR
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