mbed TLS v2.24.0
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crypto_sizes.h File Reference

PSA cryptography module: Mbed TLS buffer size macros. More...

#include "mbedtls/config.h"
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Macros

#define PSA_BITS_TO_BYTES(bits)   (((bits) + 7) / 8)
 
#define PSA_BYTES_TO_BITS(bytes)   ((bytes) * 8)
 
#define PSA_ROUND_UP_TO_MULTIPLE(block_size, length)   (((length) + (block_size) - 1) / (block_size) * (block_size))
 
#define PSA_HASH_SIZE(alg)
 
#define PSA_HASH_MAX_SIZE   64
 
#define PSA_HMAC_MAX_HASH_BLOCK_SIZE   128
 
#define PSA_MAC_MAX_SIZE   PSA_HASH_MAX_SIZE
 
#define PSA_AEAD_TAG_LENGTH(alg)
 
#define PSA_VENDOR_RSA_MAX_KEY_BITS   4096
 
#define PSA_VENDOR_ECC_MAX_CURVE_BITS   521
 
#define PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN   128
 
#define PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE   16
 
#define PSA_MAC_FINAL_SIZE(key_type, key_bits, alg)
 
#define PSA_AEAD_ENCRYPT_OUTPUT_SIZE(alg, plaintext_length)
 
#define PSA_AEAD_DECRYPT_OUTPUT_SIZE(alg, ciphertext_length)
 
#define PSA_AEAD_UPDATE_OUTPUT_SIZE(alg, input_length)
 
#define PSA_AEAD_FINISH_OUTPUT_SIZE(alg)
 
#define PSA_AEAD_VERIFY_OUTPUT_SIZE(alg)
 
#define PSA_RSA_MINIMUM_PADDING_SIZE(alg)
 
#define PSA_ECDSA_SIGNATURE_SIZE(curve_bits)   (PSA_BITS_TO_BYTES(curve_bits) * 2)
 ECDSA signature size for a given curve bit size. More...
 
#define PSA_SIGN_OUTPUT_SIZE(key_type, key_bits, alg)
 
#define PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE   PSA_ECDSA_SIGNATURE_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)
 
#define PSA_SIGNATURE_MAX_SIZE
 
#define PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(key_type, key_bits, alg)
 
#define PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(key_type, key_bits, alg)
 
#define PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(bits)   ((bits) / 8 + 5)
 
#define PSA_KEY_EXPORT_RSA_PUBLIC_KEY_MAX_SIZE(key_bits)   (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) + 11)
 
#define PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE(key_bits)   (9 * PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE((key_bits) / 2 + 1) + 14)
 
#define PSA_KEY_EXPORT_DSA_PUBLIC_KEY_MAX_SIZE(key_bits)   (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 59)
 
#define PSA_KEY_EXPORT_DSA_KEY_PAIR_MAX_SIZE(key_bits)   (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 75)
 
#define PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(key_bits)   (2 * PSA_BITS_TO_BYTES(key_bits) + 1)
 
#define PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(key_bits)   (PSA_BITS_TO_BYTES(key_bits))
 
#define PSA_KEY_EXPORT_MAX_SIZE(key_type, key_bits)
 

Detailed Description

PSA cryptography module: Mbed TLS buffer size macros.

Note
This file may not be included directly. Applications must include psa/crypto.h.

This file contains the definitions of macros that are useful to compute buffer sizes. The signatures and semantics of these macros are standardized, but the definitions are not, because they depend on the available algorithms and, in some cases, on permitted tolerances on buffer sizes.

In implementations with isolation between the application and the cryptography module, implementers should take care to ensure that the definitions that are exposed to applications match what the module implements.

Macros that compute sizes whose values do not depend on the implementation are in crypto.h.

Definition in file crypto_sizes.h.

Macro Definition Documentation

#define PSA_AEAD_DECRYPT_OUTPUT_SIZE (   alg,
  ciphertext_length 
)
Value:
(PSA_AEAD_TAG_LENGTH(alg) != 0 ? \
(ciphertext_length) - PSA_AEAD_TAG_LENGTH(alg) : \
0)
#define PSA_AEAD_TAG_LENGTH(alg)
Definition: crypto_sizes.h:139

The maximum size of the output of psa_aead_decrypt(), in bytes.

If the size of the plaintext buffer is at least this large, it is guaranteed that psa_aead_decrypt() will not fail due to an insufficient buffer size. Depending on the algorithm, the actual size of the plaintext may be smaller.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
ciphertext_lengthSize of the plaintext in bytes.
Returns
The AEAD ciphertext size for the specified algorithm. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 276 of file crypto_sizes.h.

#define PSA_AEAD_ENCRYPT_OUTPUT_SIZE (   alg,
  plaintext_length 
)
Value:
(PSA_AEAD_TAG_LENGTH(alg) != 0 ? \
(plaintext_length) + PSA_AEAD_TAG_LENGTH(alg) : \
0)
#define PSA_AEAD_TAG_LENGTH(alg)
Definition: crypto_sizes.h:139

The maximum size of the output of psa_aead_encrypt(), in bytes.

If the size of the ciphertext buffer is at least this large, it is guaranteed that psa_aead_encrypt() will not fail due to an insufficient buffer size. Depending on the algorithm, the actual size of the ciphertext may be smaller.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
plaintext_lengthSize of the plaintext in bytes.
Returns
The AEAD ciphertext size for the specified algorithm. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 252 of file crypto_sizes.h.

#define PSA_AEAD_FINISH_OUTPUT_SIZE (   alg)
Value:
0)
#define PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE
Definition: crypto_sizes.h:208
#define PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg)

A sufficient ciphertext buffer size for psa_aead_finish().

If the size of the ciphertext buffer is at least this large, it is guaranteed that psa_aead_finish() will not fail due to an insufficient ciphertext buffer size. The actual size of the output may be smaller in any given call.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
Returns
A sufficient ciphertext buffer size for the specified algorithm. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 327 of file crypto_sizes.h.

#define PSA_AEAD_TAG_LENGTH (   alg)
Value:
(PSA_ALG_IS_AEAD(alg) ? \
0)
#define PSA_AEAD_TAG_LENGTH_OFFSET
#define PSA_ALG_AEAD_TAG_LENGTH_MASK
#define PSA_ALG_IS_AEAD(alg)

The tag size for an AEAD algorithm, in bytes.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
Returns
The tag size for the specified algorithm. If the AEAD algorithm does not have an identified tag that can be distinguished from the rest of the ciphertext, return 0. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 139 of file crypto_sizes.h.

#define PSA_AEAD_UPDATE_OUTPUT_SIZE (   alg,
  input_length 
)
Value:
(input_length))
#define PSA_ROUND_UP_TO_MULTIPLE(block_size, length)
Definition: crypto_sizes.h:54
#define PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE
Definition: crypto_sizes.h:208
#define PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg)

A sufficient output buffer size for psa_aead_update().

If the size of the output buffer is at least this large, it is guaranteed that psa_aead_update() will not fail due to an insufficient buffer size. The actual size of the output may be smaller in any given call.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
input_lengthSize of the input in bytes.
Returns
A sufficient output buffer size for the specified algorithm. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 304 of file crypto_sizes.h.

#define PSA_AEAD_VERIFY_OUTPUT_SIZE (   alg)
Value:
0)
#define PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE
Definition: crypto_sizes.h:208
#define PSA_ALG_IS_AEAD_ON_BLOCK_CIPHER(alg)

A sufficient plaintext buffer size for psa_aead_verify().

If the size of the plaintext buffer is at least this large, it is guaranteed that psa_aead_verify() will not fail due to an insufficient plaintext buffer size. The actual size of the output may be smaller in any given call.

Parameters
algAn AEAD algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_AEAD(alg) is true).
Returns
A sufficient plaintext buffer size for the specified algorithm. If the AEAD algorithm is not recognized, return 0. An implementation may return either 0 or a correct size for an AEAD algorithm that it recognizes, but does not support.

Definition at line 350 of file crypto_sizes.h.

#define PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN   128

This macro returns the maximum length of the PSK supported by the TLS-1.2 PSK-to-MS key derivation.

Quoting RFC 4279, Sect 5.3: TLS implementations supporting these ciphersuites MUST support arbitrary PSK identities up to 128 octets in length, and arbitrary PSKs up to 64 octets in length. Supporting longer identities and keys is RECOMMENDED.

Therefore, no implementation should define a value smaller than 64 for PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN.

Definition at line 205 of file crypto_sizes.h.

#define PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE (   key_type,
  key_bits,
  alg 
)
Value:
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
0)
#define PSA_RSA_MINIMUM_PADDING_SIZE(alg)
Definition: crypto_sizes.h:355
#define PSA_KEY_TYPE_IS_RSA(type)
#define PSA_BITS_TO_BYTES(bits)
Definition: crypto_sizes.h:51

Sufficient output buffer size for psa_asymmetric_decrypt().

This macro returns a sufficient buffer size for a plaintext produced using a key of the specified type and size, with the specified algorithm. Note that the actual size of the plaintext may be smaller, depending on the algorithm.

Warning
This function may call its arguments multiple times or zero times, so you should not pass arguments that contain side effects.
Parameters
key_typeAn asymmetric key type (this may indifferently be a key pair type or a public key type).
key_bitsThe size of the key in bits.
algThe asymmetric encryption algorithm.
Returns
If the parameters are valid and supported, return a buffer size in bytes that guarantees that psa_asymmetric_decrypt() will not fail with PSA_ERROR_BUFFER_TOO_SMALL. If the parameters are a valid combination that is not supported by the implementation, this macro shall return either a sensible size or 0. If the parameters are not valid, the return value is unspecified.

Definition at line 475 of file crypto_sizes.h.

#define PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE (   key_type,
  key_bits,
  alg 
)
Value:
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
0)
#define PSA_KEY_TYPE_IS_RSA(type)
#define PSA_BITS_TO_BYTES(bits)
Definition: crypto_sizes.h:51

Sufficient output buffer size for psa_asymmetric_encrypt().

This macro returns a sufficient buffer size for a ciphertext produced using a key of the specified type and size, with the specified algorithm. Note that the actual size of the ciphertext may be smaller, depending on the algorithm.

Warning
This function may call its arguments multiple times or zero times, so you should not pass arguments that contain side effects.
Parameters
key_typeAn asymmetric key type (this may indifferently be a key pair type or a public key type).
key_bitsThe size of the key in bits.
algThe asymmetric encryption algorithm.
Returns
If the parameters are valid and supported, return a buffer size in bytes that guarantees that psa_asymmetric_encrypt() will not fail with PSA_ERROR_BUFFER_TOO_SMALL. If the parameters are a valid combination that is not supported by the implementation, this macro shall return either a sensible size or 0. If the parameters are not valid, the return value is unspecified.

Definition at line 444 of file crypto_sizes.h.

#define PSA_BITS_TO_BYTES (   bits)    (((bits) + 7) / 8)

Definition at line 51 of file crypto_sizes.h.

#define PSA_BYTES_TO_BITS (   bytes)    ((bytes) * 8)

Definition at line 52 of file crypto_sizes.h.

#define PSA_ECDSA_SIGNATURE_SIZE (   curve_bits)    (PSA_BITS_TO_BYTES(curve_bits) * 2)

ECDSA signature size for a given curve bit size.

Parameters
curve_bitsCurve size in bits.
Returns
Signature size in bytes.
Note
This macro returns a compile-time constant if its argument is one.

Definition at line 368 of file crypto_sizes.h.

#define PSA_HASH_MAX_SIZE   64

Maximum size of a hash.

This macro must expand to a compile-time constant integer. This value should be the maximum size of a hash supported by the implementation, in bytes, and must be no smaller than this maximum.

Definition at line 102 of file crypto_sizes.h.

#define PSA_HASH_SIZE (   alg)
Value:
( \
0)
#define PSA_ALG_SHA3_256
#define PSA_ALG_SHA3_224
#define PSA_ALG_MD4
#define PSA_ALG_SHA3_512
#define PSA_ALG_SHA_256
#define PSA_ALG_SHA_512
#define PSA_ALG_SHA_224
#define PSA_ALG_RIPEMD160
#define PSA_ALG_SHA_384
#define PSA_ALG_SHA_512_224
#define PSA_ALG_HMAC_GET_HASH(hmac_alg)
#define PSA_ALG_SHA_512_256
#define PSA_ALG_MD2
#define PSA_ALG_SHA_1
#define PSA_ALG_MD5
#define PSA_ALG_SHA3_384

The size of the output of psa_hash_finish(), in bytes.

This is also the hash size that psa_hash_verify() expects.

Parameters
algA hash algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_HASH(alg) is true), or an HMAC algorithm (PSA_ALG_HMAC(hash_alg) where hash_alg is a hash algorithm).
Returns
The hash size for the specified hash algorithm. If the hash algorithm is not recognized, return 0. An implementation may return either 0 or the correct size for a hash algorithm that it recognizes, but does not support.

Definition at line 71 of file crypto_sizes.h.

#define PSA_HMAC_MAX_HASH_BLOCK_SIZE   128

Definition at line 103 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE (   bits)    ((bits) / 8 + 5)

Definition at line 490 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_DSA_KEY_PAIR_MAX_SIZE (   key_bits)    (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 75)

Definition at line 567 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_DSA_PUBLIC_KEY_MAX_SIZE (   key_bits)    (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) * 3 + 59)

Definition at line 548 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE (   key_bits)    (PSA_BITS_TO_BYTES(key_bits))

Definition at line 587 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE (   key_bits)    (2 * PSA_BITS_TO_BYTES(key_bits) + 1)

Definition at line 580 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_MAX_SIZE (   key_type,
  key_bits 
)
Value:
0)
#define PSA_KEY_TYPE_DSA_PUBLIC_KEY
Definition: crypto_extra.h:330
#define PSA_KEY_TYPE_DSA_KEY_PAIR
Definition: crypto_extra.h:348
#define PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:587
#define PSA_KEY_TYPE_RSA_KEY_PAIR
#define PSA_KEY_TYPE_IS_UNSTRUCTURED(type)
#define PSA_KEY_TYPE_IS_ECC_KEY_PAIR(type)
#define PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:529
#define PSA_KEY_TYPE_RSA_PUBLIC_KEY
#define PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:580
#define PSA_KEY_EXPORT_DSA_KEY_PAIR_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:567
#define PSA_KEY_TYPE_IS_ECC_PUBLIC_KEY(type)
#define PSA_KEY_EXPORT_DSA_PUBLIC_KEY_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:548
#define PSA_KEY_EXPORT_RSA_PUBLIC_KEY_MAX_SIZE(key_bits)
Definition: crypto_sizes.h:504
#define PSA_BITS_TO_BYTES(bits)
Definition: crypto_sizes.h:51

Sufficient output buffer size for psa_export_key() or psa_export_public_key().

This macro returns a compile-time constant if its arguments are compile-time constants.

Warning
This function may call its arguments multiple times or zero times, so you should not pass arguments that contain side effects.

The following code illustrates how to allocate enough memory to export a key by querying the key type and size at runtime.

psa_status_t status;
status = psa_get_key_attributes(key, &attributes);
if (status != PSA_SUCCESS) handle_error(...);
psa_key_type_t key_type = psa_get_key_type(&attributes);
size_t key_bits = psa_get_key_bits(&attributes);
size_t buffer_size = PSA_KEY_EXPORT_MAX_SIZE(key_type, key_bits);
uint8_t *buffer = malloc(buffer_size);
if (buffer == NULL) handle_error(...);
size_t buffer_length;
status = psa_export_key(key, buffer, buffer_size, &buffer_length);
if (status != PSA_SUCCESS) handle_error(...);

For psa_export_public_key(), calculate the buffer size from the public key type. You can use the macro PSA_KEY_TYPE_PUBLIC_KEY_OF_KEY_PAIR to convert a key pair type to the corresponding public key type.

psa_status_t status;
status = psa_get_key_attributes(key, &attributes);
if (status != PSA_SUCCESS) handle_error(...);
psa_key_type_t key_type = psa_get_key_type(&attributes);
size_t key_bits = psa_get_key_bits(&attributes);
size_t buffer_size = PSA_KEY_EXPORT_MAX_SIZE(public_key_type, key_bits);
uint8_t *buffer = malloc(buffer_size);
if (buffer == NULL) handle_error(...);
size_t buffer_length;
status = psa_export_public_key(key, buffer, buffer_size, &buffer_length);
if (status != PSA_SUCCESS) handle_error(...);
Parameters
key_typeA supported key type.
key_bitsThe size of the key in bits.
Returns
If the parameters are valid and supported, return a buffer size in bytes that guarantees that psa_sign_hash() will not fail with PSA_ERROR_BUFFER_TOO_SMALL. If the parameters are a valid combination that is not supported by the implementation, this macro shall return either a sensible size or 0. If the parameters are not valid, the return value is unspecified.

Definition at line 650 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_RSA_KEY_PAIR_MAX_SIZE (   key_bits)    (9 * PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE((key_bits) / 2 + 1) + 14)

Definition at line 529 of file crypto_sizes.h.

#define PSA_KEY_EXPORT_RSA_PUBLIC_KEY_MAX_SIZE (   key_bits)    (PSA_KEY_EXPORT_ASN1_INTEGER_MAX_SIZE(key_bits) + 11)

Definition at line 504 of file crypto_sizes.h.

#define PSA_MAC_FINAL_SIZE (   key_type,
  key_bits,
  alg 
)
Value:
((void)(key_type), (void)(key_bits), 0))
#define PSA_HASH_SIZE(alg)
Definition: crypto_sizes.h:71
#define PSA_ALG_IS_BLOCK_CIPHER_MAC(alg)
#define PSA_ALG_MAC_TRUNCATION_MASK
#define PSA_ALG_HMAC_GET_HASH(hmac_alg)
#define PSA_BLOCK_CIPHER_BLOCK_SIZE(type)
#define PSA_MAC_TRUNCATED_LENGTH(mac_alg)
#define PSA_ALG_IS_HMAC(alg)

The size of the output of psa_mac_sign_finish(), in bytes.

This is also the MAC size that psa_mac_verify_finish() expects.

Parameters
key_typeThe type of the MAC key.
key_bitsThe size of the MAC key in bits.
algA MAC algorithm (PSA_ALG_XXX value such that PSA_ALG_IS_MAC(alg) is true).
Returns
The MAC size for the specified algorithm with the specified key parameters.
0 if the MAC algorithm is not recognized.
Either 0 or the correct size for a MAC algorithm that the implementation recognizes, but does not support.
Unspecified if the key parameters are not consistent with the algorithm.

Definition at line 227 of file crypto_sizes.h.

#define PSA_MAC_MAX_SIZE   PSA_HASH_MAX_SIZE

Maximum size of a MAC.

This macro must expand to a compile-time constant integer. This value should be the maximum size of a MAC supported by the implementation, in bytes, and must be no smaller than this maximum.

Definition at line 122 of file crypto_sizes.h.

#define PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE   16

The maximum size of a block cipher supported by the implementation.

Definition at line 208 of file crypto_sizes.h.

#define PSA_ROUND_UP_TO_MULTIPLE (   block_size,
  length 
)    (((length) + (block_size) - 1) / (block_size) * (block_size))

Definition at line 54 of file crypto_sizes.h.

#define PSA_RSA_MINIMUM_PADDING_SIZE (   alg)
Value:
11 /*PKCS#1v1.5*/)
#define PSA_HASH_SIZE(alg)
Definition: crypto_sizes.h:71
#define PSA_ALG_RSA_OAEP_GET_HASH(alg)
#define PSA_ALG_IS_RSA_OAEP(alg)

Definition at line 355 of file crypto_sizes.h.

#define PSA_SIGN_OUTPUT_SIZE (   key_type,
  key_bits,
  alg 
)
Value:
(PSA_KEY_TYPE_IS_RSA(key_type) ? ((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
((void)alg, 0))
#define PSA_KEY_TYPE_IS_RSA(type)
#define PSA_ECDSA_SIGNATURE_SIZE(curve_bits)
ECDSA signature size for a given curve bit size.
Definition: crypto_sizes.h:368
#define PSA_KEY_TYPE_IS_ECC(type)
#define PSA_BITS_TO_BYTES(bits)
Definition: crypto_sizes.h:51

Sufficient signature buffer size for psa_sign_hash().

This macro returns a sufficient buffer size for a signature using a key of the specified type and size, with the specified algorithm. Note that the actual size of the signature may be smaller (some algorithms produce a variable-size signature).

Warning
This function may call its arguments multiple times or zero times, so you should not pass arguments that contain side effects.
Parameters
key_typeAn asymmetric key type (this may indifferently be a key pair type or a public key type).
key_bitsThe size of the key in bits.
algThe signature algorithm.
Returns
If the parameters are valid and supported, return a buffer size in bytes that guarantees that psa_sign_hash() will not fail with PSA_ERROR_BUFFER_TOO_SMALL. If the parameters are a valid combination that is not supported by the implementation, this macro shall return either a sensible size or 0. If the parameters are not valid, the return value is unspecified.

Definition at line 397 of file crypto_sizes.h.

#define PSA_SIGNATURE_MAX_SIZE
Value:

Maximum size of an asymmetric signature.

This macro must expand to a compile-time constant integer. This value should be the maximum size of a signature supported by the implementation, in bytes, and must be no smaller than this maximum.

Definition at line 413 of file crypto_sizes.h.

#define PSA_VENDOR_ECC_MAX_CURVE_BITS   521

Definition at line 162 of file crypto_sizes.h.

#define PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE   PSA_ECDSA_SIGNATURE_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)

Definition at line 402 of file crypto_sizes.h.

#define PSA_VENDOR_RSA_MAX_KEY_BITS   4096

Definition at line 157 of file crypto_sizes.h.