class OpenSSL::PKey::RSA

RSA is an asymmetric public key algorithm that has been formalized in RFC 3447. It is in widespread use in public key infrastructures (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.

Constants

NO_PADDING
PKCS1_OAEP_PADDING
PKCS1_PADDING
SSLV23_PADDING

Public Class Methods

generate(size, exponent = 65537) → RSA click to toggle source

Generates an RSA keypair.

See also OpenSSL::PKey.generate_key.

size

The desired key size in bits.

exponent

An odd Integer, normally 3, 17, or 65537.

# File ext/openssl/lib/openssl/pkey.rb, line 305
def generate(size, exp = 0x10001, &blk)
  OpenSSL::PKey.generate_key("RSA", {
    "rsa_keygen_bits" => size,
    "rsa_keygen_pubexp" => exp,
  }, &blk)
end
new → rsa click to toggle source
new(encoded_key [, passphrase]) → rsa
new(encoded_key) { passphrase } → rsa
new(size [, exponent]) → rsa

Generates or loads an RSA keypair.

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

If called with a String, tries to parse as DER or PEM encoding of an RSA key. Note that, if passphrase is not specified but the key is encrypted with a passphrase, OpenSSL will prompt for it. See also OpenSSL::PKey.read which can parse keys of any kinds.

If called with a number, generates a new key pair. This form works as an alias of RSA.generate.

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

    GetPKey(self, pkey);
    /* The RSA.new(size, generator) form is handled by lib/openssl/pkey.rb */
    rb_scan_args(argc, argv, "02", &arg, &pass);
    if (argc == 0) {
        rsa = RSA_new();
        if (!rsa)
            ossl_raise(eRSAError, "RSA_new");
    }
    else {
        pass = ossl_pem_passwd_value(pass);
        arg = ossl_to_der_if_possible(arg);
        in = ossl_obj2bio(&arg);

        tmp = ossl_pkey_read_generic(in, pass);
        if (tmp) {
            if (EVP_PKEY_base_id(tmp) != EVP_PKEY_RSA)
                rb_raise(eRSAError, "incorrect pkey type: %s",
                         OBJ_nid2sn(EVP_PKEY_base_id(tmp)));
            rsa = EVP_PKEY_get1_RSA(tmp);
            EVP_PKEY_free(tmp);
        }
        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_clear_error();
            ossl_raise(eRSAError, "Neither PUB key nor PRIV key");
        }
    }
    if (!EVP_PKEY_assign_RSA(pkey, rsa)) {
        RSA_free(rsa);
        ossl_raise(eRSAError, "EVP_PKEY_assign_RSA");
    }

    return self;
}

Public Instance Methods

export([cipher, pass_phrase]) → PEM-format String click to toggle source

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 instance.

static VALUE
ossl_rsa_export(int argc, VALUE *argv, VALUE self)
{
    if (can_export_rsaprivatekey(self))
        return ossl_pkey_export_traditional(argc, argv, self, 0);
    else
        return ossl_pkey_export_spki(self, 0);
}
Also aliased as: to_pem, to_s
initialize_copy(p1) click to toggle source
static VALUE
ossl_rsa_initialize_copy(VALUE self, VALUE other)
{
    EVP_PKEY *pkey;
    RSA *rsa, *rsa_new;

    GetPKey(self, pkey);
    if (EVP_PKEY_base_id(pkey) != EVP_PKEY_NONE)
        ossl_raise(eRSAError, "RSA already initialized");
    GetRSA(other, rsa);

    rsa_new = ASN1_dup((i2d_of_void *)i2d_RSAPrivateKey, (d2i_of_void *)d2i_RSAPrivateKey, (char *)rsa);
    if (!rsa_new)
        ossl_raise(eRSAError, "ASN1_dup");

    EVP_PKEY_assign_RSA(pkey, rsa_new);

    return self;
}
params → hash click to toggle source

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)

static VALUE
ossl_rsa_get_params(VALUE self)
{
    RSA *rsa;
    VALUE hash;
    const BIGNUM *n, *e, *d, *p, *q, *dmp1, *dmq1, *iqmp;

    GetRSA(self, rsa);
    RSA_get0_key(rsa, &n, &e, &d);
    RSA_get0_factors(rsa, &p, &q);
    RSA_get0_crt_params(rsa, &dmp1, &dmq1, &iqmp);

    hash = rb_hash_new();
    rb_hash_aset(hash, rb_str_new2("n"), ossl_bn_new(n));
    rb_hash_aset(hash, rb_str_new2("e"), ossl_bn_new(e));
    rb_hash_aset(hash, rb_str_new2("d"), ossl_bn_new(d));
    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("dmp1"), ossl_bn_new(dmp1));
    rb_hash_aset(hash, rb_str_new2("dmq1"), ossl_bn_new(dmq1));
    rb_hash_aset(hash, rb_str_new2("iqmp"), ossl_bn_new(iqmp));

    return hash;
}
private? → true | false click to toggle source

Does this keypair contain a private key?

static VALUE
ossl_rsa_is_private(VALUE self)
{
    RSA *rsa;

    GetRSA(self, rsa);

    return RSA_PRIVATE(self, rsa) ? Qtrue : Qfalse;
}
private_decrypt(string) → String click to toggle source
private_decrypt(string, padding) → String

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

Deprecated in version 3.0. Consider using PKey::PKey#encrypt and PKey::PKey#decrypt instead.

# File ext/openssl/lib/openssl/pkey.rb, line 397
def private_decrypt(data, padding = PKCS1_PADDING)
  n or raise OpenSSL::PKey::RSAError, "incomplete RSA"
  private? or raise OpenSSL::PKey::RSAError, "private key needed."
  begin
    decrypt(data, {
      "rsa_padding_mode" => translate_padding_mode(padding),
    })
  rescue OpenSSL::PKey::PKeyError
    raise OpenSSL::PKey::RSAError, $!.message
  end
end
private_encrypt(string) → String click to toggle source
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.

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

# File ext/openssl/lib/openssl/pkey.rb, line 334
def private_encrypt(string, padding = PKCS1_PADDING)
  n or raise OpenSSL::PKey::RSAError, "incomplete RSA"
  private? or raise OpenSSL::PKey::RSAError, "private key needed."
  begin
    sign_raw(nil, string, {
      "rsa_padding_mode" => translate_padding_mode(padding),
    })
  rescue OpenSSL::PKey::PKeyError
    raise OpenSSL::PKey::RSAError, $!.message
  end
end
public? → true click to toggle source

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

static VALUE
ossl_rsa_is_public(VALUE self)
{
    RSA *rsa;

    GetRSA(self, rsa);
    /*
     * This method should check for n and e.  BUG.
     */
    (void)rsa;
    return Qtrue;
}
public_decrypt(string) → String click to toggle source
public_decrypt(string, padding) → String

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

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

# File ext/openssl/lib/openssl/pkey.rb, line 356
def public_decrypt(string, padding = PKCS1_PADDING)
  n or raise OpenSSL::PKey::RSAError, "incomplete RSA"
  begin
    verify_recover(nil, string, {
      "rsa_padding_mode" => translate_padding_mode(padding),
    })
  rescue OpenSSL::PKey::PKeyError
    raise OpenSSL::PKey::RSAError, $!.message
  end
end
public_encrypt(string) → String click to toggle source
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.

Deprecated in version 3.0. Consider using PKey::PKey#encrypt and PKey::PKey#decrypt instead.

# File ext/openssl/lib/openssl/pkey.rb, line 377
def public_encrypt(data, padding = PKCS1_PADDING)
  n or raise OpenSSL::PKey::RSAError, "incomplete RSA"
  begin
    encrypt(data, {
      "rsa_padding_mode" => translate_padding_mode(padding),
    })
  rescue OpenSSL::PKey::PKeyError
    raise OpenSSL::PKey::RSAError, $!.message
  end
end
public_key → rsanew click to toggle source

Returns a new RSA instance that carries just the public key components.

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.

# File ext/openssl/lib/openssl/pkey.rb, line 289
def public_key
  OpenSSL::PKey.read(public_to_der)
end
set_crt_params(dmp1, dmq1, iqmp) → self

Sets dmp1, dmq1, iqmp for the RSA instance. They are calculated by d mod (p - 1), d mod (q - 1) and q^(-1) mod p respectively.

set_factors(p, q) → self

Sets p, q for the RSA instance.

set_key(n, e, d) → self

Sets n, e, d for the RSA instance.

sign_pss(digest, data, salt_length:, mgf1_hash:) → String click to toggle source

Signs data using the Probabilistic Signature Scheme (RSA-PSS) and returns the calculated signature.

RSAError will be raised if an error occurs.

See verify_pss for the verification operation.

Parameters

digest

A String containing the message digest algorithm name.

data

A String. The data to be signed.

salt_length

The length in octets of the salt. Two special values are reserved: :digest means the digest length, and :max means the maximum possible length for the combination of the private key and the selected message digest algorithm.

mgf1_hash

The hash algorithm used in MGF1 (the currently supported mask generation function (MGF)).

Example

data = "Sign me!"
pkey = OpenSSL::PKey::RSA.new(2048)
signature = pkey.sign_pss("SHA256", data, salt_length: :max, mgf1_hash: "SHA256")
pub_key = OpenSSL::PKey.read(pkey.public_to_der)
puts pub_key.verify_pss("SHA256", signature, data,
                        salt_length: :auto, mgf1_hash: "SHA256") # => true
static VALUE
ossl_rsa_sign_pss(int argc, VALUE *argv, VALUE self)
{
    VALUE digest, data, options, kwargs[2], signature;
    static ID kwargs_ids[2];
    EVP_PKEY *pkey;
    EVP_PKEY_CTX *pkey_ctx;
    const EVP_MD *md, *mgf1md;
    EVP_MD_CTX *md_ctx;
    size_t buf_len;
    int salt_len;

    if (!kwargs_ids[0]) {
        kwargs_ids[0] = rb_intern_const("salt_length");
        kwargs_ids[1] = rb_intern_const("mgf1_hash");
    }
    rb_scan_args(argc, argv, "2:", &digest, &data, &options);
    rb_get_kwargs(options, kwargs_ids, 2, 0, kwargs);
    if (kwargs[0] == ID2SYM(rb_intern("max")))
        salt_len = -2; /* RSA_PSS_SALTLEN_MAX_SIGN */
    else if (kwargs[0] == ID2SYM(rb_intern("digest")))
        salt_len = -1; /* RSA_PSS_SALTLEN_DIGEST */
    else
        salt_len = NUM2INT(kwargs[0]);
    mgf1md = ossl_evp_get_digestbyname(kwargs[1]);

    pkey = GetPrivPKeyPtr(self);
    buf_len = EVP_PKEY_size(pkey);
    md = ossl_evp_get_digestbyname(digest);
    StringValue(data);
    signature = rb_str_new(NULL, (long)buf_len);

    md_ctx = EVP_MD_CTX_new();
    if (!md_ctx)
        goto err;

    if (EVP_DigestSignInit(md_ctx, &pkey_ctx, md, NULL, pkey) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, salt_len) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1md) != 1)
        goto err;

    if (EVP_DigestSignUpdate(md_ctx, RSTRING_PTR(data), RSTRING_LEN(data)) != 1)
        goto err;

    if (EVP_DigestSignFinal(md_ctx, (unsigned char *)RSTRING_PTR(signature), &buf_len) != 1)
        goto err;

    rb_str_set_len(signature, (long)buf_len);

    EVP_MD_CTX_free(md_ctx);
    return signature;

  err:
    EVP_MD_CTX_free(md_ctx);
    ossl_raise(eRSAError, NULL);
}
to_der → DER-format String click to toggle source

Outputs this keypair in DER encoding.

static VALUE
ossl_rsa_to_der(VALUE self)
{
    if (can_export_rsaprivatekey(self))
        return ossl_pkey_export_traditional(0, NULL, self, 1);
    else
        return ossl_pkey_export_spki(self, 1);
}
to_pem([cipher, pass_phrase]) → PEM-format String

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 instance.

Alias for: export
to_s([cipher, pass_phrase]) → PEM-format String

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 instance.

Alias for: export
verify_pss(digest, signature, data, salt_length:, mgf1_hash:) → true | false click to toggle source

Verifies data using the Probabilistic Signature Scheme (RSA-PSS).

The return value is true if the signature is valid, false otherwise. RSAError will be raised if an error occurs.

See sign_pss for the signing operation and an example code.

Parameters

digest

A String containing the message digest algorithm name.

data

A String. The data to be signed.

salt_length

The length in octets of the salt. Two special values are reserved: :digest means the digest length, and :auto means automatically determining the length based on the signature.

mgf1_hash

The hash algorithm used in MGF1.

static VALUE
ossl_rsa_verify_pss(int argc, VALUE *argv, VALUE self)
{
    VALUE digest, signature, data, options, kwargs[2];
    static ID kwargs_ids[2];
    EVP_PKEY *pkey;
    EVP_PKEY_CTX *pkey_ctx;
    const EVP_MD *md, *mgf1md;
    EVP_MD_CTX *md_ctx;
    int result, salt_len;

    if (!kwargs_ids[0]) {
        kwargs_ids[0] = rb_intern_const("salt_length");
        kwargs_ids[1] = rb_intern_const("mgf1_hash");
    }
    rb_scan_args(argc, argv, "3:", &digest, &signature, &data, &options);
    rb_get_kwargs(options, kwargs_ids, 2, 0, kwargs);
    if (kwargs[0] == ID2SYM(rb_intern("auto")))
        salt_len = -2; /* RSA_PSS_SALTLEN_AUTO */
    else if (kwargs[0] == ID2SYM(rb_intern("digest")))
        salt_len = -1; /* RSA_PSS_SALTLEN_DIGEST */
    else
        salt_len = NUM2INT(kwargs[0]);
    mgf1md = ossl_evp_get_digestbyname(kwargs[1]);

    GetPKey(self, pkey);
    md = ossl_evp_get_digestbyname(digest);
    StringValue(signature);
    StringValue(data);

    md_ctx = EVP_MD_CTX_new();
    if (!md_ctx)
        goto err;

    if (EVP_DigestVerifyInit(md_ctx, &pkey_ctx, md, NULL, pkey) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, salt_len) != 1)
        goto err;

    if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1md) != 1)
        goto err;

    if (EVP_DigestVerifyUpdate(md_ctx, RSTRING_PTR(data), RSTRING_LEN(data)) != 1)
        goto err;

    result = EVP_DigestVerifyFinal(md_ctx,
                                   (unsigned char *)RSTRING_PTR(signature),
                                   RSTRING_LEN(signature));

    switch (result) {
      case 0:
        ossl_clear_error();
        EVP_MD_CTX_free(md_ctx);
        return Qfalse;
      case 1:
        EVP_MD_CTX_free(md_ctx);
        return Qtrue;
      default:
        goto err;
    }

  err:
    EVP_MD_CTX_free(md_ctx);
    ossl_raise(eRSAError, NULL);
}

Private Instance Methods

translate_padding_mode(num) click to toggle source
# File ext/openssl/lib/openssl/pkey.rb, line 414
        def translate_padding_mode(num)
  case num
  when PKCS1_PADDING
    "pkcs1"
  when SSLV23_PADDING
    "sslv23"
  when NO_PADDING
    "none"
  when PKCS1_OAEP_PADDING
    "oaep"
  else
    raise OpenSSL::PKey::PKeyError, "unsupported padding mode"
  end
end