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Class: OpenSSL::PKey::DSA

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, PKey
Instance Chain:
Inherits: OpenSSL::PKey::PKey
Defined in: ext/openssl/ossl_pkey_dsa.c,
ext/openssl/lib/openssl/pkey.rb

Overview

DSA, the Digital Signature Algorithm, is specified in NIST’s FIPS 186-3. It is an asymmetric public key algorithm that may be used similar to e.g. RSA.

Class Method Summary

  • .generate(size) ⇒ DSA

    Creates a new DSA instance by generating a private/public key pair from scratch.

  • .new ⇒ DSA constructor Internal use only

    Creates a new DSA instance by reading an existing key from string.

PKey - Inherited

.new

Because PKey is an abstract class, actually calling this method explicitly will raise a NotImplementedError.

Instance Attribute Summary

  • #private? ⇒ Boolean readonly

    Indicates whether this DSA instance has a private key associated with it or not.

  • #public? ⇒ Boolean readonly

    Indicates whether this DSA instance has a public key associated with it or not.

Instance Method Summary

::OpenSSL::Marshal - Included

PKey - Inherited

#compare?

Used primarily to check if an X509::Certificate#public_key compares to its private key.

#decrypt

Performs a public key decryption operation using pkey.

#derive

Derives a shared secret from pkey and peer_pkey.

#encrypt

Performs a public key encryption operation using pkey.

#initialize_copy,
#inspect

Returns a string describing the PKey object.

#oid

Returns the short name of the OID associated with pkey.

#private_to_der

Serializes the private key to DER-encoded PKCS #8 format.

#private_to_pem

Serializes the private key to PEM-encoded PKCS #8 format.

#public_to_der

Serializes the public key to DER-encoded X.509 SubjectPublicKeyInfo format.

#public_to_pem

Serializes the public key to PEM-encoded X.509 SubjectPublicKeyInfo format.

#sign

Hashes and signs the data using a message digest algorithm digest and a private key pkey.

#sign_raw

Signs data using a private key pkey.

#to_text

Dumps key parameters, public key, and private key components contained in the key into a human-readable text.

#verify

Verifies the signature for the data using a message digest algorithm digest and a public key pkey.

#verify_raw

Verifies the signature for the data using a public key pkey.

#verify_recover

Recovers the signed data from signature using a public key pkey.

Constructor Details

.newDSA .new(string [, pass]) ⇒ DSA .new(size) ⇒ DSA

This method is for internal use only.

Creates a new DSA instance by reading an existing key from string.

If called without arguments, creates a new instance with no key components set. They can be set individually by #set_pqg and #set_key.

If called with a String, tries to parse as DER or PEM encoding of a DSA key. See also OpenSSL::PKey.read which can parse keys of any kinds.

If called with a number, generates random parameters and a key pair. This form works as an alias of .generate.

string

A String that contains a DER or PEM encoded key.

pass

A String that contains an optional password.

size

See DSA.generate.

Examples:

p OpenSSL::PKey::DSA.new(1024)
#=> #<OpenSSL::PKey::DSA:0x000055a8d6025bf0 oid=DSA>

p OpenSSL::PKey::DSA.new(File.read('dsa.pem'))
#=> #<OpenSSL::PKey::DSA:0x000055555d6b8110 oid=DSA>

p OpenSSL::PKey::DSA.new(File.read('dsa.pem'), 'mypassword')
#=> #<OpenSSL::PKey::DSA:0x0000556f973c40b8 oid=DSA>
[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 83

static VALUE
ossl_dsa_initialize(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    DSA *dsa;
    BIO *in = NULL;
    VALUE arg, pass;
    int type;

    TypedData_Get_Struct(self, EVP_PKEY, &ossl_evp_pkey_type, pkey);
    if (pkey)
        rb_raise(rb_eTypeError, "pkey already initialized");

    /* The DSA.new(size, generator) form is handled by lib/openssl/pkey.rb */
    rb_scan_args(argc, argv, "02", &arg, &pass);
    if (argc == 0) {
        dsa = DSA_new();
        if (!dsa)
            ossl_raise(eDSAError, "DSA_new");
        goto legacy;
    }

    pass = ossl_pem_passwd_value(pass);
    arg = ossl_to_der_if_possible(arg);
    in = ossl_obj2bio(&arg);

    /* DER-encoded DSAPublicKey format isn't supported by the generic routine */
    dsa = (DSA *)PEM_ASN1_read_bio((d2i_of_void *)d2i_DSAPublicKey,
                                   PEM_STRING_DSA_PUBLIC,
                                   in, NULL, NULL, NULL);
    if (dsa)
        goto legacy;
    OSSL_BIO_reset(in);

    pkey = ossl_pkey_read_generic(in, pass);
    BIO_free(in);
    if (!pkey)
        ossl_raise(eDSAError, "Neither PUB key nor PRIV key");

    type = EVP_PKEY_base_id(pkey);
    if (type != EVP_PKEY_DSA) {
        EVP_PKEY_free(pkey);
        rb_raise(eDSAError, "incorrect pkey type: %s", OBJ_nid2sn(type));
    }
    RTYPEDDATA_DATA(self) = pkey;
    return self;

  legacy:
    BIO_free(in);
    pkey = EVP_PKEY_new();
    if (!pkey || EVP_PKEY_assign_DSA(pkey, dsa) != 1) {
        EVP_PKEY_free(pkey);
        DSA_free(dsa);
        ossl_raise(eDSAError, "EVP_PKEY_assign_DSA");
    }
    RTYPEDDATA_DATA(self) = pkey;
    return self;
}

Class Method Details

.generate(size) ⇒ DSA

Creates a new DSA instance by generating a private/public key pair from scratch.

See also OpenSSL::PKey.generate_parameters and OpenSSL::PKey.generate_key.

size

The desired key size in bits.

[ GitHub ]

  
# File 'ext/openssl/lib/openssl/pkey.rb', line 169

def generate(size, &blk)
  # FIPS 186-4 specifies four (L,N) pairs: (1024,160), (2048,224),
  # (2048,256), and (3072,256).
  #
  # q size is derived here with compatibility with
  # DSA_generator_parameters_ex() which previous versions of ruby/openssl
  # used to call.
  qsize = size >= 2048 ? 256 : 160
  dsaparams = OpenSSL::PKey.generate_parameters("DSA", {
    "dsa_paramgen_bits" => size,
    "dsa_paramgen_q_bits" => qsize,
  }, &blk)
  OpenSSL::PKey.generate_key(dsaparams)
end

Instance Attribute Details

#private?Boolean (readonly)

Indicates whether this DSA instance has a private key associated with it or not. The private key may be retrieved with DSA#private_key.

[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 198

static VALUE
ossl_dsa_is_private(VALUE self)
{
    OSSL_3_const DSA *dsa;

    GetDSA(self, dsa);

    return DSA_PRIVATE(self, dsa) ? Qtrue : Qfalse;
}

#public?Boolean (readonly)

Indicates whether this DSA instance has a public key associated with it or not. The public key may be retrieved with #public_key.

[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 179

static VALUE
ossl_dsa_is_public(VALUE self)
{
    const DSA *dsa;
    const BIGNUM *bn;

    GetDSA(self, dsa);
    DSA_get0_key(dsa, &bn, NULL);

    return bn ? Qtrue : Qfalse;
}

Instance Method Details

#export([cipher, password]) ⇒ String #to_pem([cipher, password]) ⇒ String #to_s([cipher, password]) ⇒ String

Alias for #to_s.

#initialize_copy(other)

[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 143

static VALUE
ossl_dsa_initialize_copy(VALUE self, VALUE other)
{
    EVP_PKEY *pkey;
    DSA *dsa, *dsa_new;

    TypedData_Get_Struct(self, EVP_PKEY, &ossl_evp_pkey_type, pkey);
    if (pkey)
        rb_raise(rb_eTypeError, "pkey already initialized");
    GetDSA(other, dsa);

    dsa_new = (DSA *)ASN1_dup((i2d_of_void *)i2d_DSAPrivateKey,
                              (d2i_of_void *)d2i_DSAPrivateKey,
                              (char *)dsa);
    if (!dsa_new)
	ossl_raise(eDSAError, "ASN1_dup");

    pkey = EVP_PKEY_new();
    if (!pkey || EVP_PKEY_assign_DSA(pkey, dsa_new) != 1) {
        EVP_PKEY_free(pkey);
        DSA_free(dsa_new);
        ossl_raise(eDSAError, "EVP_PKEY_assign_DSA");
    }
    RTYPEDDATA_DATA(self) = pkey;

    return self;
}

#paramsHash

Stores all parameters of key to the hash INSECURE: PRIVATE INFORMATIONS CAN LEAK OUT!!! Don’t use :-)) (I’s up to you)

[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 265

static VALUE
ossl_dsa_get_params(VALUE self)
{
    OSSL_3_const DSA *dsa;
    VALUE hash;
    const BIGNUM *p, *q, *g, *pub_key, *priv_key;

    GetDSA(self, dsa);
    DSA_get0_pqg(dsa, &p, &q, &g);
    DSA_get0_key(dsa, &pub_key, &priv_key);

    hash = rb_hash_new();
    rb_hash_aset(hash, rb_str_new2("p"), ossl_bn_new(p));
    rb_hash_aset(hash, rb_str_new2("q"), ossl_bn_new(q));
    rb_hash_aset(hash, rb_str_new2("g"), ossl_bn_new(g));
    rb_hash_aset(hash, rb_str_new2("pub_key"), ossl_bn_new(pub_key));
    rb_hash_aset(hash, rb_str_new2("priv_key"), ossl_bn_new(priv_key));

    return hash;
}

#public_keyDSA

Returns a new DSA instance that carries just the DSA parameters and the public key.

This method is provided for backwards compatibility. In most cases, there is no need to call this method.

For the purpose of serializing the public key, to PEM or DER encoding of X.509 SubjectPublicKeyInfo format, check PKey#public_to_pem and PKey#public_to_der.

[ GitHub ]

  
# File 'ext/openssl/lib/openssl/pkey.rb', line 153

def public_key
  OpenSSL::PKey.read(public_to_der)
end

#set_key(pub_key, priv_key) ⇒ self

Sets pub_key and priv_key for the DSA instance. priv_key may be nil.

[ GitHub ]

#set_pqg(p, q, g) ⇒ self

Sets p, q, g to the DSA instance.

[ GitHub ]

#syssign(string) ⇒ String

Computes and returns the DSA signature of string, where string is expected to be an already-computed message digest of the original input data. The signature is issued using the private key of this DSA instance.

Deprecated in version 3.0. Consider using PKey#sign_raw and PKey#verify_raw instead.

string

A message digest of the original input data to be signed.

Example:

dsa = OpenSSL::PKey::DSA.new(2048)
doc = "Sign me"
digest = OpenSSL::Digest.digest('SHA1', doc)

# With legacy #syssign and #sysverify:
sig = dsa.syssign(digest)
p dsa.sysverify(digest, sig) #=> true

# With #sign_raw and #verify_raw:
sig = dsa.sign_raw(nil, digest)
p dsa.verify_raw(nil, sig, digest) #=> true
[ GitHub ]

  
# File 'ext/openssl/lib/openssl/pkey.rb', line 220

def syssign(string)
  q or raise OpenSSL::PKey::DSAError, "incomplete DSA"
  private? or raise OpenSSL::PKey::DSAError, "Private DSA key needed!"
  begin
    sign_raw(nil, string)
  rescue OpenSSL::PKey::PKeyError
    raise OpenSSL::PKey::DSAError, $!.message
  end
end

#sysverify(digest, sig) ⇒ Boolean

Verifies whether the signature is valid given the message digest input. It does so by validating sig using the public key of this DSA instance.

Deprecated in version 3.0. Consider using PKey#sign_raw and PKey#verify_raw instead.

digest

A message digest of the original input data to be signed.

sig

A DSA signature value.

[ GitHub ]

  
# File 'ext/openssl/lib/openssl/pkey.rb', line 243

def sysverify(digest, sig)
  verify_raw(nil, sig, digest)
rescue OpenSSL::PKey::PKeyError
  raise OpenSSL::PKey::DSAError, $!.message
end

#to_derString

Encodes this DSA to its DER encoding.

[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 244

static VALUE
ossl_dsa_to_der(VALUE self)
{
    OSSL_3_const DSA *dsa;

    GetDSA(self, dsa);
    if (DSA_HAS_PRIVATE(dsa))
        return ossl_pkey_export_traditional(0, NULL, self, 1);
    else
        return ossl_pkey_export_spki(self, 1);
}

#export([cipher, password]) ⇒ String #to_pem([cipher, password]) ⇒ String #to_s([cipher, password]) ⇒ String

Alias for #to_s.

#export([cipher, password]) ⇒ String #to_pem([cipher, password]) ⇒ String #to_s([cipher, password]) ⇒ String
Also known as: #export, #to_pem

Encodes this DSA to its PEM encoding.

Parameters

Examples

DSA.to_pem -> aString
DSA.to_pem(cipher, 'mypassword') -> aString
[ GitHub ]

  
# File 'ext/openssl/ossl_pkey_dsa.c', line 225

static VALUE
ossl_dsa_export(int argc, VALUE *argv, VALUE self)
{
    OSSL_3_const DSA *dsa;

    GetDSA(self, dsa);
    if (DSA_HAS_PRIVATE(dsa))
        return ossl_pkey_export_traditional(argc, argv, self, 0);
    else
        return ossl_pkey_export_spki(self, 0);
}