| ? Generic/ASN.1 | AlgorithmParameters |
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
(Although the 'parameters' field is marked "OPTIONAL" in the ASN.1
syntax, it MUST be given in this context.)
This format is not algorithm-specific, since the 'algorithm' field specifies the key family, and therefore keys from different families (e.g. RSA, DSA, etc.) can be unambiguously distinguished.
Generic/ASN.1 SHOULD normally be implemented by expressing the algorithm OID as a dot-separated string, then looking up an algorithm-specific AlgorithmParameters implementation based on that string, e.g. "1.2.3.4" if the OID is { 1 2 3 4 }. This allows new public key algorithms to be added without having to change existing classes.
Output MUST be encoded as DER.
| × DH/ASN.1 | AlgorithmParameters |
DHParameters ::= SEQUENCE {
version INTEGER, -- always 1
usageFlags INTEGER, -- see below
p INTEGER, -- p
g INTEGER, -- g
order INTEGER OPTIONAL -- order of subgroup generated by g
}
usageFlags is either 1 (i.e. bit 0 is set), indicating that the key
pair is to be used for encryption, or 4 (i.e. bit 2 is set),
indicating that it is to be used for key agreement.
Output MUST be encoded as DER.
| × DSA/ASN.1 | AlgorithmParameters |
DSAParameters ::= SEQUENCE {
version INTEGER, -- always 1
usageFlags INTEGER, -- see below
p INTEGER, -- p
g INTEGER, -- g
q INTEGER, -- q
}
usageFlags is either 2 (i.e. bit 1 is set), indicating that the key
pair is to be used for signatures on data, or 6 (i.e. bits 1 and
2 are set), indicating that it is to be used for signing messages
sent in a key agreement protocol.
Output MUST be encoded as DER.
| ? ECDH/ASN.1 | AlgorithmParameters |
ECParameters ::= SEQUENCE {
version INTEGER { ecpVer1(1) } (ecpVer1),
-- version is always 1
fieldID FieldID { {FieldTypes} },
-- the finite field over which the curve is defined
curve Curve,
-- coefficients a and b of the elliptic curve
base ECPoint,
-- the base point P on the elliptic curve
order INTEGER,
-- the order n of the base point
cofactor INTEGER,
-- #E(Fq)/n (used only in parameter validation)
...
}
FieldElement ::= OCTET STRING
Curve ::= SEQUENCE {
a FieldElement,
b FieldElement,
seed BIT STRING OPTIONAL
}
ECPoint ::= OCTET STRING
FieldID { FIELD-ID:IOSet } ::= SEQUENCE {
fieldType FIELD-ID.&id({IOSet}),
parameters FIELD-ID.&Type({IOSet}{@fieldType}) OPTIONAL
}
FieldTypes FIELD-ID ::= {
{ Prime-p IDENTIFIED BY prime-field } |
{ Characteristic-two
IDENTIFIED BY characteristic-two-field },
...
}
FIELD-ID ::= TYPE-IDENTIFIER
Output MUST be encoded as DER.
| ? ECDSA/ASN.1 | AlgorithmParameters |
Output MUST be encoded as DER.
| × ESIGN/ASN.1 | AlgorithmParameters |
We define a new ESIGNParameters type (not taken from any existing standard) as follows:
ESIGNParameters ::= SEQUENCE {
version INTEGER, -- always 1
usageFlags INTEGER, -- see below
modulusLength INTEGER, -- bitlength(n)
publicExponent INTEGER OPTIONAL -- e
}
usageFlags is either 2 (i.e. bit 1 is set), indicating that the key
pair is to be used for signatures on data, or 6 (i.e. bits 1 and
2 are set), indicating that it is to be used for signing messages
sent in a key agreement protocol.
A missing 'publicExponent' field indicates that a random full-length public exponent will be generated.
Implementations MUST also accept an ASN.1 NULL in place of the ESIGNParameters object. In this case a dummy AlgorithmParameters object, containing no parameters, will be generated.
Output MUST be encoded as DER.
| × RSA/ASN.1 | AlgorithmParameters |
We define a new RSAParameters type (not taken from any existing standard) as follows:
RSAParameters ::= SEQUENCE {
version INTEGER, -- always 1
usageFlags INTEGER, -- see below
modulusLength INTEGER, -- bitlength(n)
publicExponent INTEGER OPTIONAL -- e
}
usageFlags has bit 0 set if the key pair is to be used for encryption,
bit 1 set if the key pair is to be used for signatures, and bit 2 set
if the key pair is to be used for key agreement. Other bits are reserved
for future use, and should be set to zero.
If bit 2 is set, then bit 0 or 1 should also be set to indicate how the key agreement algorithm uses the RSA primitive.
The purpose of the usage flags is to allow implementations to detect cases where an RSA key are used in an unexpected context, e.g. when a signing-only key is used for encryption or vice-versa.
A missing 'publicExponent' field indicates that a random full-length public exponent will be generated.
Implementations MUST also accept an ASN.1 NULL in place of the RSAParameters object. In this case a dummy AlgorithmParameters object, containing no parameters, will be generated.
Output MUST be encoded as DER.
| × RW/ASN.1 | AlgorithmParameters |
We define a new RWParameters type (not taken from any existing standard) as follows:
RWParameters ::= SEQUENCE {
version INTEGER, -- always 1
usageFlags INTEGER, -- see below
modulusLength INTEGER -- bitlength(n)
}
usageFlags is either 2 (i.e. bit 1 is set), indicating that the key
pair is to be used for signatures on data, or 6 (i.e. bits 1 and
2 are set), indicating that it is to be used for signing messages
sent in a key agreement protocol.
Implementations MUST also accept an ASN.1 NULL in place of the RWParameters object. In this case a dummy AlgorithmParameters object, containing no parameters, will be generated.
Output MUST be encoded as DER.
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