Module: OpenSSL::Random
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Exceptions:
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Defined in: | ext/openssl/ossl_rand.c |
Class Attribute Summary
-
.status? ⇒ Boolean
readonly
mod_func
Return
true
if the PRNG has been seeded with enough data,false
otherwise.
Class Method Summary
-
.egd(filename) ⇒ true
mod_func
Same as .egd_bytes but queries 255 bytes by default.
-
.egd_bytes(filename, length) ⇒ true
mod_func
Queries the entropy gathering daemon EGD on socket path given by filename.
-
.load_random_file(filename) ⇒ true
mod_func
Reads bytes from filename and adds them to the PRNG.
-
.pseudo_bytes(length) ⇒ String
mod_func
Generates a String with length number of pseudo-random bytes.
-
.add(str, entropy) ⇒ self
mod_func
Mixes the bytes from str into the Pseudo Random Number Generator(PRNG) state.
-
.random_bytes(length) ⇒ String
mod_func
Generates a String with length number of cryptographically strong pseudo-random bytes.
-
.seed(str) ⇒ String
mod_func
.seed is equivalent to
.add
where entropy is length of str. -
.write_random_file(filename) ⇒ true
mod_func
Writes a number of random generated bytes (currently 1024) to filename which can be used to initialize the PRNG by calling .load_random_file in a later session.
Class Attribute Details
.status? ⇒ Boolean
(readonly, mod_func)
Return true
if the PRNG has been seeded with enough data, false
otherwise.
# File 'ext/openssl/ossl_rand.c', line 204
static VALUE ossl_rand_status(VALUE self) { return RAND_status() ? Qtrue : Qfalse; }
Class Method Details
.egd(filename) ⇒ true
(mod_func)
Same as .egd_bytes but queries 255 bytes by default.
# File 'ext/openssl/ossl_rand.c', line 164
static VALUE ossl_rand_egd(VALUE self, VALUE filename) { rb_check_safe_obj(filename); if (RAND_egd(StringValueCStr(filename)) == -1) { ossl_raise(eRandomError, NULL); } return Qtrue; }
.egd_bytes(filename, length) ⇒ true
(mod_func)
Queries the entropy gathering daemon EGD on socket path given by filename.
Fetches length number of bytes and uses .add
to seed the ::OpenSSL
built-in PRNG.
# File 'ext/openssl/ossl_rand.c', line 184
static VALUE ossl_rand_egd_bytes(VALUE self, VALUE filename, VALUE len) { int n = NUM2INT(len); rb_check_safe_obj(filename); if (RAND_egd_bytes(StringValueCStr(filename), n) == -1) { ossl_raise(eRandomError, NULL); } return Qtrue; }
.load_random_file(filename) ⇒ true
(mod_func)
Reads bytes from filename and adds them to the PRNG.
# File 'ext/openssl/ossl_rand.c', line 67
static VALUE ossl_rand_load_file(VALUE self, VALUE filename) { rb_check_safe_obj(filename); if(!RAND_load_file(StringValueCStr(filename), -1)) { ossl_raise(eRandomError, NULL); } return Qtrue; }
.pseudo_bytes(length) ⇒ String
(mod_func)
Generates a String with length number of pseudo-random bytes.
Pseudo-random byte sequences generated by .pseudo_bytes
will be unique if they are of sufficient length, but are not necessarily unpredictable.
Example
OpenSSL::Random.pseudo_bytes(12)
#=> "..."
# File 'ext/openssl/ossl_rand.c', line 142
static VALUE ossl_rand_pseudo_bytes(VALUE self, VALUE len) { VALUE str; int n = NUM2INT(len); str = rb_str_new(0, n); if (RAND_pseudo_bytes((unsigned char *)RSTRING_PTR(str), n) < 1) { ossl_raise(eRandomError, NULL); } return str; }
.add(str, entropy) ⇒ self
(mod_func)
Mixes the bytes from str into the Pseudo Random Number Generator(PRNG) state.
Thus, if the data from str are unpredictable to an adversary, this increases the uncertainty about the state and makes the PRNG output less predictable.
The entropy argument is (the lower bound of) an estimate of how much randomness is contained in str, measured in bytes.
Example
pid = $$
now = Time.now
ary = [now.to_i, now.nsec, 1000, pid]
OpenSSL::Random.add(ary.join, 0.0)
OpenSSL::Random.seed(ary.join)
# File 'ext/openssl/ossl_rand.c', line 52
static VALUE ossl_rand_add(VALUE self, VALUE str, VALUE entropy) { StringValue(str); RAND_add(RSTRING_PTR(str), RSTRING_LENINT(str), NUM2DBL(entropy)); return self; }
.random_bytes(length) ⇒ String
(mod_func)
Generates a String with length number of cryptographically strong pseudo-random bytes.
Example
OpenSSL::Random.random_bytes(12)
#=> "..."
# File 'ext/openssl/ossl_rand.c', line 109
static VALUE ossl_rand_bytes(VALUE self, VALUE len) { VALUE str; int n = NUM2INT(len); int ret; str = rb_str_new(0, n); ret = RAND_bytes((unsigned char *)RSTRING_PTR(str), n); if (ret == 0) { ossl_raise(eRandomError, "RAND_bytes"); } else if (ret == -1) { ossl_raise(eRandomError, "RAND_bytes is not supported"); } return str; }
.seed(str) ⇒ String
(mod_func)
.seed
is equivalent to .add
where entropy is length of str.
# File 'ext/openssl/ossl_rand.c', line 21
static VALUE ossl_rand_seed(VALUE self, VALUE str) { StringValue(str); RAND_seed(RSTRING_PTR(str), RSTRING_LENINT(str)); return str; }
.write_random_file(filename) ⇒ true
(mod_func)
Writes a number of random generated bytes (currently 1024) to filename which can be used to initialize the PRNG by calling .load_random_file in a later session.
# File 'ext/openssl/ossl_rand.c', line 86
static VALUE ossl_rand_write_file(VALUE self, VALUE filename) { rb_check_safe_obj(filename); if (RAND_write_file(StringValueCStr(filename)) == -1) { ossl_raise(eRandomError, NULL); } return Qtrue; }