1 // Copyright 2023 Google LLC 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef THIRD_PARTY_ANONYMOUS_TOKENS_CPP_CRYPTO_CONSTANTS_H_ 16 #define THIRD_PARTY_ANONYMOUS_TOKENS_CPP_CRYPTO_CONSTANTS_H_ 17 18 #include <cstdint> 19 20 #include "absl/strings/string_view.h" 21 22 namespace private_membership { 23 namespace anonymous_tokens { 24 25 // Returned integer on successful execution of BoringSSL methods 26 constexpr int kBsslSuccess = 1; 27 28 // RSA modulus size, 4096 bits 29 // 30 // Our recommended size. 31 constexpr int kRsaModulusSizeInBits4096 = 4096; 32 33 // RSA modulus size, 512 bytes 34 constexpr int kRsaModulusSizeInBytes512 = 512; 35 36 // RSA modulus size, 2048 bits 37 // 38 // Recommended size for RSA Blind Signatures without Public Metadata. 39 // 40 // https://www.ietf.org/archive/id/draft-ietf-privacypass-protocol-08.html#name-token-type-blind-rsa-2048-b. 41 constexpr int kRsaModulusSizeInBits2048 = 2048; 42 43 // RSA modulus size, 256 bytes 44 constexpr int kRsaModulusSizeInBytes256 = 256; 45 46 // Salt length, 48 bytes 47 // 48 // Recommended size. The convention is to use hLen, the length of the output of 49 // the hash function in bytes. A salt length of zero will result in a 50 // deterministic signature value. 51 // 52 // https://datatracker.ietf.org/doc/draft-irtf-cfrg-rsa-blind-signatures/ 53 constexpr int kSaltLengthInBytes48 = 48; 54 55 // Length of message mask, 32 bytes. 56 // 57 // https://datatracker.ietf.org/doc/draft-irtf-cfrg-rsa-blind-signatures/ 58 constexpr int kRsaMessageMaskSizeInBytes32 = 32; 59 60 // Info used in HKDF for Public Metadata Hash. 61 constexpr absl::string_view kHkdfPublicMetadataInfo = "PBRSA"; 62 63 constexpr int kHkdfPublicMetadataInfoSizeInBytes = 5; 64 65 } // namespace anonymous_tokens 66 } // namespace private_membership 67 68 #endif // THIRD_PARTY_ANONYMOUS_TOKENS_CPP_CRYPTO_CONSTANTS_H_ 69