Botan 3.4.0
Crypto and TLS for C&
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#include <ct_utils.h>
Public Member Functions | |
constexpr bool | as_bool () const |
constexpr T | if_not_set_return (T x) const |
constexpr T | if_set_return (T x) const |
constexpr void | if_set_zero_out (T buf[], size_t elems) |
Mask (const Mask< T > &other)=default | |
template<typename U > | |
constexpr | Mask (Mask< U > o) |
Mask< T > & | operator&= (Mask< T > o) |
Mask< T > & | operator= (const Mask< T > &other)=default |
Mask< T > & | operator^= (Mask< T > o) |
Mask< T > & | operator|= (Mask< T > o) |
constexpr Mask< T > | operator~ () const |
constexpr T | select (T x, T y) const |
constexpr T | select_and_unpoison (T x, T y) const |
Mask< T > | select_mask (Mask< T > x, Mask< T > y) const |
constexpr void | select_n (T output[], const T x[], const T y[], size_t len) const |
constexpr T | unpoisoned_value () const |
constexpr T | value () const |
Static Public Member Functions | |
static constexpr Mask< T > | cleared () |
template<typename U > | |
static constexpr Mask< T > | expand (Mask< U > m) |
static constexpr Mask< T > | expand (T v) |
static constexpr Mask< T > | is_any_of (T v, std::initializer_list< T > accepted) |
static constexpr Mask< T > | is_equal (T x, T y) |
static constexpr Mask< T > | is_gt (T x, T y) |
static constexpr Mask< T > | is_gte (T x, T y) |
static constexpr Mask< T > | is_lt (T x, T y) |
static constexpr Mask< T > | is_lte (T x, T y) |
static constexpr Mask< T > | is_within_range (T v, T l, T u) |
static constexpr Mask< T > | is_zero (T x) |
static constexpr Mask< T > | set () |
Friends | |
Mask< T > | operator& (Mask< T > x, Mask< T > y) |
Mask< T > | operator^ (Mask< T > x, Mask< T > y) |
Mask< T > | operator| (Mask< T > x, Mask< T > y) |
A Mask type used for constant-time operations. A Mask<T> always has value either 0 (all bits cleared) or ~0 (all bits set). All operations in a Mask<T> are intended to compile to code which does not contain conditional jumps. This must be verified with tooling (eg binary disassembly or using valgrind) since you never know what a compiler might do.
Definition at line 86 of file ct_utils.h.
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default |
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inlineconstexpr |
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inlineconstexpr |
Return true iff this mask is set
Definition at line 278 of file ct_utils.h.
References Botan::CT::Mask< T >::unpoisoned_value().
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inlinestaticconstexpr |
Return a Mask<T> with all bits cleared
Definition at line 110 of file ct_utils.h.
Referenced by Botan::low_zero_bits(), Botan::oaep_find_delim(), Botan::OneAndZeros_Padding::unpad(), Botan::EME_PKCS1v15::unpad(), and Botan::x448().
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inlinestaticconstexpr |
Return a Mask<T> which is set if m is set
Definition at line 121 of file ct_utils.h.
References T, and Botan::CT::Mask< T >::value().
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inlinestaticconstexpr |
Return a Mask<T> which is set if v is != 0
Definition at line 115 of file ct_utils.h.
Referenced by Botan::bigint_cnd_abs(), Botan::bigint_cnd_add(), Botan::bigint_cnd_sub(), Botan::bigint_cnd_swap(), Botan::bigint_ct_is_lt(), Botan::bigint_shl1(), Botan::bigint_shl2(), Botan::bigint_shr1(), Botan::bigint_shr2(), Botan::Scalar448::bytes_are_reduced(), Botan::BigInt::cond_flip_sign(), Botan::CT::conditional_assign_mem(), Botan::CT::conditional_copy_mem(), Botan::CT::conditional_swap(), Botan::constant_time_compare(), Botan::CT::copy_output(), Botan::BigInt::ct_cond_assign(), Botan::ct_divide_word(), Botan::Ed448Point::decode(), Botan::low_zero_bits(), Botan::Ed448Point::operator==(), Botan::redc_p521(), Botan::Sodium::sodium_is_zero(), Botan::ANSI_X923_Padding::unpad(), Botan::OneAndZeros_Padding::unpad(), and Botan::x448().
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inlineconstexpr |
Return x if the mask is cleared, or otherwise zero
Definition at line 229 of file ct_utils.h.
Referenced by Botan::CT::Mask< T >::if_set_zero_out(), and Botan::EME_PKCS1v15::unpad().
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inlineconstexpr |
Return x if the mask is set, or otherwise zero
Definition at line 224 of file ct_utils.h.
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inlineconstexpr |
If this mask is set, zero out buf, otherwise do nothing
Definition at line 260 of file ct_utils.h.
References Botan::CT::Mask< T >::if_not_set_return().
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inlinestaticconstexpr |
Definition at line 165 of file ct_utils.h.
References Botan::expand_top_bit(), and T.
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inlinestaticconstexpr |
Return a Mask<T> which is set if x == y
Definition at line 134 of file ct_utils.h.
References Botan::CT::Mask< T >::is_zero(), and T.
Referenced by Botan::bigint_cmp(), Botan::bigint_ct_is_lt(), Botan::TLS::check_tls_cbc_padding(), Botan::constant_time_compare(), Botan::CT::copy_output(), Botan::PK_Decryptor::decrypt_or_random(), Botan::EC_Point_Base_Point_Precompute::mul(), Botan::EC_Point_Var_Point_Precompute::mul(), Botan::oaep_find_delim(), Botan::redc_p521(), Botan::Sodium::sodium_compare(), Botan::PKCS7_Padding::unpad(), Botan::OneAndZeros_Padding::unpad(), Botan::ESP_Padding::unpad(), and Botan::vartime_divide().
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inlinestaticconstexpr |
Return a Mask<T> which is set if x > y
Definition at line 144 of file ct_utils.h.
References Botan::CT::Mask< T >::is_lt().
Referenced by Botan::CT::copy_output(), Botan::PKCS7_Padding::unpad(), Botan::ANSI_X923_Padding::unpad(), and Botan::ESP_Padding::unpad().
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inlinestaticconstexpr |
Return a Mask<T> which is set if x >= y
Definition at line 154 of file ct_utils.h.
Referenced by Botan::ct_divide_word(), Botan::PKCS7_Padding::unpad(), and Botan::ANSI_X923_Padding::unpad().
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inlinestaticconstexpr |
Return a Mask<T> which is set if x < y
Definition at line 139 of file ct_utils.h.
Referenced by Botan::bigint_cmp(), Botan::bigint_ct_is_lt(), Botan::TLS::check_tls_cbc_padding(), Botan::CT::Mask< T >::is_gt(), Botan::FrodoMatrix::sample(), and Botan::Sodium::sodium_compare().
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inlinestaticconstexpr |
Return a Mask<T> which is set if x <= y
Definition at line 149 of file ct_utils.h.
Referenced by Botan::TLS::check_tls_cbc_padding(), and Botan::constant_time_compare().
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inlinestaticconstexpr |
Definition at line 156 of file ct_utils.h.
References Botan::expand_top_bit(), and T.
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inlinestaticconstexpr |
Return a Mask<T> which is set if v is == 0 or cleared otherwise
Definition at line 129 of file ct_utils.h.
Referenced by Botan::CT::all_zeros(), Botan::bigint_cmp(), Botan::bigint_ct_is_eq(), Botan::bigint_ct_is_lt(), Botan::BigInt::ct_reduce_below(), Botan::CT::is_equal(), Botan::CT::Mask< T >::is_equal(), Botan::oaep_find_delim(), Botan::CT::strip_leading_zeros(), Botan::OneAndZeros_Padding::unpad(), Botan::ESP_Padding::unpad(), and Botan::EME_PKCS1v15::unpad().
AND-combine two masks
Definition at line 180 of file ct_utils.h.
References Botan::CT::Mask< T >::value().
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default |
XOR-combine two masks
Definition at line 188 of file ct_utils.h.
References Botan::CT::Mask< T >::value().
OR-combine two masks
Definition at line 196 of file ct_utils.h.
References Botan::CT::Mask< T >::value().
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inlineconstexpr |
Negate this mask
Definition at line 219 of file ct_utils.h.
References Botan::CT::Mask< T >::value().
If this mask is set, return x, otherwise return y
Definition at line 234 of file ct_utils.h.
References Botan::choose(), and Botan::CT::Mask< T >::value().
Referenced by Botan::bigint_cnd_add_or_sub(), Botan::CT::Mask< T >::select_and_unpoison(), Botan::CT::Mask< T >::select_mask(), and Botan::CT::Mask< T >::select_n().
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inlineconstexpr |
Definition at line 236 of file ct_utils.h.
References Botan::CT::Mask< T >::select(), T, and Botan::CT::unpoison().
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inline |
If this mask is set, return x, otherwise return y
Definition at line 245 of file ct_utils.h.
References Botan::CT::Mask< T >::select(), and Botan::CT::Mask< T >::value().
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inlineconstexpr |
Conditionally set output to x or y, depending on if mask is set or cleared (resp)
Definition at line 251 of file ct_utils.h.
References Botan::CT::Mask< T >::select().
Referenced by Botan::CT::conditional_copy_mem().
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inlinestaticconstexpr |
Return a Mask<T> with all bits set
Definition at line 105 of file ct_utils.h.
References T.
Referenced by Botan::oaep_find_delim(), and Botan::CT::strip_leading_zeros().
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inlineconstexpr |
Return the value of the mask, unpoisoned
Definition at line 269 of file ct_utils.h.
References T, Botan::CT::unpoison(), and Botan::CT::Mask< T >::value().
Referenced by Botan::CT::Mask< T >::as_bool().
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inlineconstexpr |
Return the underlying value of the mask
Definition at line 283 of file ct_utils.h.
Referenced by Botan::CT::Mask< T >::expand(), Botan::CT::Mask< T >::operator&=(), Botan::CT::Mask< T >::operator^=(), Botan::CT::Mask< T >::operator|=(), Botan::CT::Mask< T >::operator~(), Botan::CT::Mask< T >::select(), Botan::CT::Mask< T >::select_mask(), and Botan::CT::Mask< T >::unpoisoned_value().
AND-combine two masks
Definition at line 204 of file ct_utils.h.
XOR-combine two masks
Definition at line 209 of file ct_utils.h.
OR-combine two masks
Definition at line 214 of file ct_utils.h.