dnssec-keygen — DNSSEC key generation tool
dnssec-keygen {-a algorithm} {-b keysize} {-n nametype} [-c ] [class-e] [-f ] [flag-g ] [generator-h] [-k] [-p ] [protocol-r ] [randomdev-s ] [strength-t ] [type-v ] {name}level
dnssec-keygen generates keys for DNSSEC (Secure DNS), as defined in RFC 2535 and RFC 4034. It can also generate keys for use with TSIG (Transaction Signatures), as defined in RFC 2845.
algorithm
Selects the cryptographic algorithm. The value of
algorithm must be one of RSAMD5 (RSA) or RSASHA1,
DSA, DH (Diffie Hellman), or HMAC-MD5. These values
are case insensitive.
Note 1: that for DNSSEC, RSASHA1 is a mandatory to implement algorithm, and DSA is recommended. For TSIG, HMAC-MD5 is mandatory.
Note 2: HMAC-MD5 and DH automatically set the -k flag.
keysizeSpecifies the number of bits in the key. The choice of key size depends on the algorithm used. RSAMD5 / RSASHA1 keys must be between 512 and 2048 bits. Diffie Hellman keys must be between 128 and 4096 bits. DSA keys must be between 512 and 1024 bits and an exact multiple of 64. HMAC-MD5 keys must be between 1 and 512 bits.
nametype
Specifies the owner type of the key. The value of
nametype must either be ZONE (for a DNSSEC
zone key (KEY/DNSKEY)), HOST or ENTITY (for a key associated with
a host (KEY)),
USER (for a key associated with a user(KEY)) or OTHER (DNSKEY).
These values are
case insensitive.
classIndicates that the DNS record containing the key should have the specified class. If not specified, class IN is used.
If generating an RSAMD5/RSASHA1 key, use a large exponent.
flagSet the specified flag in the flag field of the KEY/DNSKEY record. The only recognized flag is KSK (Key Signing Key) DNSKEY.
generatorIf generating a Diffie Hellman key, use this generator. Allowed values are 2 and 5. If no generator is specified, a known prime from RFC 2539 will be used if possible; otherwise the default is 2.
Prints a short summary of the options and arguments to dnssec-keygen.
Generate KEY records rather than DNSKEY records.
protocolSets the protocol value for the generated key. The protocol is a number between 0 and 255. The default is 3 (DNSSEC). Other possible values for this argument are listed in RFC 2535 and its successors.
randomdev
Specifies the source of randomness. If the operating
system does not provide a /dev/random
or equivalent device, the default source of randomness
is keyboard input. randomdev
specifies
the name of a character device or file containing random
data to be used instead of the default. The special value
keyboard indicates that keyboard
input should be used.
strengthSpecifies the strength value of the key. The strength is a number between 0 and 15, and currently has no defined purpose in DNSSEC.
type
Indicates the use of the key. type must be
one of AUTHCONF, NOAUTHCONF, NOAUTH, or NOCONF. The default
is AUTHCONF. AUTH refers to the ability to authenticate
data, and CONF the ability to encrypt data.
levelSets the debugging level.
When dnssec-keygen completes
successfully,
it prints a string of the form Knnnn.+aaa+iiiii
to the standard output. This is an identification string for
the key it has generated.
nnnn is the key name.
aaa is the numeric representation
of the
algorithm.
iiiii is the key identifier (or
footprint).
dnssec-keygen
creates two files, with names based
on the printed string. Knnnn.+aaa+iiiii.key
contains the public key, and
Knnnn.+aaa+iiiii.private contains the
private
key.
The .key file contains a DNS KEY record
that
can be inserted into a zone file (directly or with a $INCLUDE
statement).
The .private file contains
algorithm-specific
fields. For obvious security reasons, this file does not have
general read permission.
Both .key and .private
files are generated for symmetric encryption algorithms such as
HMAC-MD5, even though the public and private key are equivalent.
To generate a 768-bit DSA key for the domain
example.com, the following command would be
issued:
dnssec-keygen -a DSA -b 768 -n ZONE example.com
The command would print a string of the form:
Kexample.com.+003+26160
In this example, dnssec-keygen creates
the files Kexample.com.+003+26160.key
and
Kexample.com.+003+26160.private.