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 <TBA\>. 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 file, 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 algorithm 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