Class: OpenSSL::PKey::RSA

Inherits:
PKey
  • Object
show all
Defined in:
ossl_pkey_rsa.c,
ossl_pkey_rsa.c

Overview

RSA is an asymmetric public key algorithm that has been formalized in RFC 3447. It is in widespread use in public key infrastuctures (PKI) where certificates (cf. OpenSSL::X509::Certificate) often are issued on the basis of a public/private RSA key pair. RSA is used in a wide field of applications such as secure (symmetric) key exchange, e.g. when establishing a secure TLS/SSL connection. It is also used in various digital signature schemes.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from PKey

#sign, #verify

Constructor Details

#new(key_size) ⇒ Object #new(encoded_key) ⇒ Object #new(encoded_key, pass_phrase) ⇒ Object

Generates or loads an RSA keypair. If an integer key_size is given it represents the desired key size. Keys less than 1024 bits should be considered insecure.

A key can instead be loaded from an encoded_key which must be PEM or DER encoded. A pass_phrase can be used to decrypt the key. If none is given OpenSSL will prompt for the pass phrase.

Examples

OpenSSL::PKey::RSA.new 2048
OpenSSL::PKey::RSA.new File.read 'rsa.pem'
OpenSSL::PKey::RSA.new File.read('rsa.pem'), 'my pass phrase'

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# File 'ossl_pkey_rsa.c', line 202

static VALUE
ossl_rsa_initialize(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    RSA *rsa;
    BIO *in;
    char *passwd = NULL;
    VALUE arg, pass;

    GetPKey(self, pkey);
    if(rb_scan_args(argc, argv, "02", &arg, &pass) == 0) {
  rsa = RSA_new();
    }
    else if (FIXNUM_P(arg)) {
  rsa = rsa_generate(FIX2INT(arg), NIL_P(pass) ? RSA_F4 : NUM2ULONG(pass));
  if (!rsa) ossl_raise(eRSAError, NULL);
    }
    else {
  if (!NIL_P(pass)) passwd = StringValuePtr(pass);
  arg = ossl_to_der_if_possible(arg);
  in = ossl_obj2bio(arg);
  rsa = PEM_read_bio_RSAPrivateKey(in, NULL, ossl_pem_passwd_cb, passwd);
  if (!rsa) {
      OSSL_BIO_reset(in);
      rsa = PEM_read_bio_RSA_PUBKEY(in, NULL, NULL, NULL);
  }
  if (!rsa) {
      OSSL_BIO_reset(in);
      rsa = d2i_RSAPrivateKey_bio(in, NULL);
  }
  if (!rsa) {
      OSSL_BIO_reset(in);
      rsa = d2i_RSA_PUBKEY_bio(in, NULL);
  }
  if (!rsa) {
      OSSL_BIO_reset(in);
      rsa = PEM_read_bio_RSAPublicKey(in, NULL, NULL, NULL);
  }
  if (!rsa) {
      OSSL_BIO_reset(in);
      rsa = d2i_RSAPublicKey_bio(in, NULL);
  }
  BIO_free(in);
  if (!rsa) {
      ossl_raise(eRSAError, "Neither PUB key nor PRIV key");
  }
    }
    if (!EVP_PKEY_assign_RSA(pkey, rsa)) {
  RSA_free(rsa);
  ossl_raise(eRSAError, NULL);
    }

    return self;
}

Class Method Details

.generate(size) ⇒ Object .generate(size, exponent) ⇒ Object

Generates an RSA keypair. size is an integer representing the desired key size. Keys smaller than 1024 should be considered insecure. exponent is an odd number normally 3, 17, or 65537.


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# File 'ossl_pkey_rsa.c', line 161

static VALUE
ossl_rsa_s_generate(int argc, VALUE *argv, VALUE klass)
{
/* why does this method exist?  why can't initialize take an optional exponent? */
    RSA *rsa;
    VALUE size, exp;
    VALUE obj;

    rb_scan_args(argc, argv, "11", &size, &exp);

    rsa = rsa_generate(NUM2INT(size), NIL_P(exp) ? RSA_F4 : NUM2ULONG(exp)); /* err handled by rsa_instance */
    obj = rsa_instance(klass, rsa);

    if (obj == Qfalse) {
  RSA_free(rsa);
  ossl_raise(eRSAError, NULL);
    }

    return obj;
}

Instance Method Details

#export([cipher, pass_phrase]) ⇒ PEM-format String #to_pem([cipher, pass_phrase]) ⇒ PEM-format String #to_s([cipher, pass_phrase]) ⇒ PEM-format String Also known as: to_pem, to_s

Outputs this keypair in PEM encoding. If cipher and pass_phrase are given they will be used to encrypt the key. cipher must be an OpenSSL::Cipher::Cipher instance.


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# File 'ossl_pkey_rsa.c', line 302

static VALUE
ossl_rsa_export(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    BIO *out;
    const EVP_CIPHER *ciph = NULL;
    char *passwd = NULL;
    VALUE cipher, pass, str;

    GetPKeyRSA(self, pkey);

    rb_scan_args(argc, argv, "02", &cipher, &pass);

    if (!NIL_P(cipher)) {
  ciph = GetCipherPtr(cipher);
  if (!NIL_P(pass)) {
      StringValue(pass);
      if (RSTRING_LENINT(pass) < OSSL_MIN_PWD_LEN)
    ossl_raise(eOSSLError, "OpenSSL requires passwords to be at least four characters long");
      passwd = RSTRING_PTR(pass);
  }
    }
    if (!(out = BIO_new(BIO_s_mem()))) {
  ossl_raise(eRSAError, NULL);
    }
    if (RSA_HAS_PRIVATE(pkey->pkey.rsa)) {
  if (!PEM_write_bio_RSAPrivateKey(out, pkey->pkey.rsa, ciph,
           NULL, 0, ossl_pem_passwd_cb, passwd)) {
      BIO_free(out);
      ossl_raise(eRSAError, NULL);
  }
    } else {
  if (!PEM_write_bio_RSA_PUBKEY(out, pkey->pkey.rsa)) {
      BIO_free(out);
      ossl_raise(eRSAError, NULL);
  }
    }
    str = ossl_membio2str(out);

    return str;
}

#paramsHash

THIS METHOD IS INSECURE, PRIVATE INFORMATION CAN LEAK OUT!!!

Stores all parameters of key to the hash. The hash has keys 'n', 'e', 'd', 'p', 'q', 'dmp1', 'dmq1', 'iqmp'.

Don't use :-)) (It's up to you)


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# File 'ossl_pkey_rsa.c', line 510

static VALUE
ossl_rsa_get_params(VALUE self)
{
    EVP_PKEY *pkey;
    VALUE hash;

    GetPKeyRSA(self, pkey);

    hash = rb_hash_new();

    rb_hash_aset(hash, rb_str_new2("n"), ossl_bn_new(pkey->pkey.rsa->n));
    rb_hash_aset(hash, rb_str_new2("e"), ossl_bn_new(pkey->pkey.rsa->e));
    rb_hash_aset(hash, rb_str_new2("d"), ossl_bn_new(pkey->pkey.rsa->d));
    rb_hash_aset(hash, rb_str_new2("p"), ossl_bn_new(pkey->pkey.rsa->p));
    rb_hash_aset(hash, rb_str_new2("q"), ossl_bn_new(pkey->pkey.rsa->q));
    rb_hash_aset(hash, rb_str_new2("dmp1"), ossl_bn_new(pkey->pkey.rsa->dmp1));
    rb_hash_aset(hash, rb_str_new2("dmq1"), ossl_bn_new(pkey->pkey.rsa->dmq1));
    rb_hash_aset(hash, rb_str_new2("iqmp"), ossl_bn_new(pkey->pkey.rsa->iqmp));

    return hash;
}

#private?Boolean

Does this keypair contain a private key?


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# File 'ossl_pkey_rsa.c', line 282

static VALUE
ossl_rsa_is_private(VALUE self)
{
    EVP_PKEY *pkey;

    GetPKeyRSA(self, pkey);

    return (RSA_PRIVATE(self, pkey->pkey.rsa)) ? Qtrue : Qfalse;
}

#private_decrypt(string) ⇒ String #private_decrypt(string, padding) ⇒ String

Decrypt string, which has been encrypted with the public key, with the private key. padding defaults to PKCS1_PADDING.


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# File 'ossl_pkey_rsa.c', line 475

static VALUE
ossl_rsa_private_decrypt(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    int buf_len, pad;
    VALUE str, buffer, padding;

    GetPKeyRSA(self, pkey);
    if (!RSA_PRIVATE(self, pkey->pkey.rsa)) {
  ossl_raise(eRSAError, "private key needed.");
    }
    rb_scan_args(argc, argv, "11", &buffer, &padding);
    pad = (argc == 1) ? RSA_PKCS1_PADDING : NUM2INT(padding);
    StringValue(buffer);
    str = rb_str_new(0, ossl_rsa_buf_size(pkey));
    buf_len = RSA_private_decrypt(RSTRING_LENINT(buffer), (unsigned char *)RSTRING_PTR(buffer),
          (unsigned char *)RSTRING_PTR(str), pkey->pkey.rsa,
          pad);
    if (buf_len < 0) ossl_raise(eRSAError, NULL);
    rb_str_set_len(str, buf_len);

    return str;
}

#private_encrypt(string) ⇒ String #private_encrypt(string, padding) ⇒ String

Encrypt string with the private key. padding defaults to PKCS1_PADDING. The encrypted string output can be decrypted using #public_decrypt.


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# File 'ossl_pkey_rsa.c', line 443

static VALUE
ossl_rsa_private_encrypt(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    int buf_len, pad;
    VALUE str, buffer, padding;

    GetPKeyRSA(self, pkey);
    if (!RSA_PRIVATE(self, pkey->pkey.rsa)) {
  ossl_raise(eRSAError, "private key needed.");
    }
    rb_scan_args(argc, argv, "11", &buffer, &padding);
    pad = (argc == 1) ? RSA_PKCS1_PADDING : NUM2INT(padding);
    StringValue(buffer);
    str = rb_str_new(0, ossl_rsa_buf_size(pkey));
    buf_len = RSA_private_encrypt(RSTRING_LENINT(buffer), (unsigned char *)RSTRING_PTR(buffer),
          (unsigned char *)RSTRING_PTR(str), pkey->pkey.rsa,
          pad);
    if (buf_len < 0) ossl_raise(eRSAError, NULL);
    rb_str_set_len(str, buf_len);

    return str;
}

#public?true

The return value is always true since every private key is also a public key.


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# File 'ossl_pkey_rsa.c', line 264

static VALUE
ossl_rsa_is_public(VALUE self)
{
    EVP_PKEY *pkey;

    GetPKeyRSA(self, pkey);
    /*
     * This method should check for n and e.  BUG.
     */
    return Qtrue;
}

#public_decrypt(string) ⇒ String #public_decrypt(string, padding) ⇒ String

Decrypt string, which has been encrypted with the private key, with the public key. padding defaults to PKCS1_PADDING.


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# File 'ossl_pkey_rsa.c', line 414

static VALUE
ossl_rsa_public_decrypt(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    int buf_len, pad;
    VALUE str, buffer, padding;

    GetPKeyRSA(self, pkey);
    rb_scan_args(argc, argv, "11", &buffer, &padding);
    pad = (argc == 1) ? RSA_PKCS1_PADDING : NUM2INT(padding);
    StringValue(buffer);
    str = rb_str_new(0, ossl_rsa_buf_size(pkey));
    buf_len = RSA_public_decrypt(RSTRING_LENINT(buffer), (unsigned char *)RSTRING_PTR(buffer),
         (unsigned char *)RSTRING_PTR(str), pkey->pkey.rsa,
         pad);
    if (buf_len < 0) ossl_raise(eRSAError, NULL);
    rb_str_set_len(str, buf_len);

    return str;
}

#public_encrypt(string) ⇒ String #public_encrypt(string, padding) ⇒ String

Encrypt string with the public key. padding defaults to PKCS1_PADDING. The encrypted string output can be decrypted using #private_decrypt.


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# File 'ossl_pkey_rsa.c', line 385

static VALUE
ossl_rsa_public_encrypt(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    int buf_len, pad;
    VALUE str, buffer, padding;

    GetPKeyRSA(self, pkey);
    rb_scan_args(argc, argv, "11", &buffer, &padding);
    pad = (argc == 1) ? RSA_PKCS1_PADDING : NUM2INT(padding);
    StringValue(buffer);
    str = rb_str_new(0, ossl_rsa_buf_size(pkey));
    buf_len = RSA_public_encrypt(RSTRING_LENINT(buffer), (unsigned char *)RSTRING_PTR(buffer),
         (unsigned char *)RSTRING_PTR(str), pkey->pkey.rsa,
         pad);
    if (buf_len < 0) ossl_raise(eRSAError, NULL);
    rb_str_set_len(str, buf_len);

    return str;
}

#public_keyObject

Makes new RSA instance containing the public key from the private key.


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# File 'ossl_pkey_rsa.c', line 568

static VALUE
ossl_rsa_to_public_key(VALUE self)
{
    EVP_PKEY *pkey;
    RSA *rsa;
    VALUE obj;

    GetPKeyRSA(self, pkey);
    /* err check performed by rsa_instance */
    rsa = RSAPublicKey_dup(pkey->pkey.rsa);
    obj = rsa_instance(CLASS_OF(self), rsa);
    if (obj == Qfalse) {
  RSA_free(rsa);
  ossl_raise(eRSAError, NULL);
    }
    return obj;
}

#to_derDER-format String

Outputs this keypair in DER encoding.


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# File 'ossl_pkey_rsa.c', line 350

static VALUE
ossl_rsa_to_der(VALUE self)
{
    EVP_PKEY *pkey;
    int (*i2d_func)_((const RSA*, unsigned char**));
    unsigned char *p;
    long len;
    VALUE str;

    GetPKeyRSA(self, pkey);
    if(RSA_HAS_PRIVATE(pkey->pkey.rsa))
  i2d_func = i2d_RSAPrivateKey;
    else
  i2d_func = (int (*)(const RSA*, unsigned char**))i2d_RSA_PUBKEY;
    if((len = i2d_func(pkey->pkey.rsa, NULL)) <= 0)
  ossl_raise(eRSAError, NULL);
    str = rb_str_new(0, len);
    p = (unsigned char *)RSTRING_PTR(str);
    if(i2d_func(pkey->pkey.rsa, &p) < 0)
  ossl_raise(eRSAError, NULL);
    ossl_str_adjust(str, p);

    return str;
}

#to_textString

THIS METHOD IS INSECURE, PRIVATE INFORMATION CAN LEAK OUT!!!

Dumps all parameters of a keypair to a String

Don't use :-)) (It's up to you)


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# File 'ossl_pkey_rsa.c', line 542

static VALUE
ossl_rsa_to_text(VALUE self)
{
    EVP_PKEY *pkey;
    BIO *out;
    VALUE str;

    GetPKeyRSA(self, pkey);
    if (!(out = BIO_new(BIO_s_mem()))) {
  ossl_raise(eRSAError, NULL);
    }
    if (!RSA_print(out, pkey->pkey.rsa, 0)) { /* offset = 0 */
  BIO_free(out);
  ossl_raise(eRSAError, NULL);
    }
    str = ossl_membio2str(out);

    return str;
}