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Diffstat (limited to 'src/crypto/aes.cpp')
| -rw-r--r-- | src/crypto/aes.cpp | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/src/crypto/aes.cpp b/src/crypto/aes.cpp new file mode 100644 index 0000000000..1d469d0fb4 --- /dev/null +++ b/src/crypto/aes.cpp @@ -0,0 +1,217 @@ +// Copyright (c) 2016 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#include "aes.h" +#include "crypto/common.h" + +#include <assert.h> +#include <string.h> + +extern "C" { +#include "crypto/ctaes/ctaes.c" +} + +AES128Encrypt::AES128Encrypt(const unsigned char key[16]) +{ + AES128_init(&ctx, key); +} + +AES128Encrypt::~AES128Encrypt() +{ + memset(&ctx, 0, sizeof(ctx)); +} + +void AES128Encrypt::Encrypt(unsigned char ciphertext[16], const unsigned char plaintext[16]) const +{ + AES128_encrypt(&ctx, 1, ciphertext, plaintext); +} + +AES128Decrypt::AES128Decrypt(const unsigned char key[16]) +{ + AES128_init(&ctx, key); +} + +AES128Decrypt::~AES128Decrypt() +{ + memset(&ctx, 0, sizeof(ctx)); +} + +void AES128Decrypt::Decrypt(unsigned char plaintext[16], const unsigned char ciphertext[16]) const +{ + AES128_decrypt(&ctx, 1, plaintext, ciphertext); +} + +AES256Encrypt::AES256Encrypt(const unsigned char key[32]) +{ + AES256_init(&ctx, key); +} + +AES256Encrypt::~AES256Encrypt() +{ + memset(&ctx, 0, sizeof(ctx)); +} + +void AES256Encrypt::Encrypt(unsigned char ciphertext[16], const unsigned char plaintext[16]) const +{ + AES256_encrypt(&ctx, 1, ciphertext, plaintext); +} + +AES256Decrypt::AES256Decrypt(const unsigned char key[32]) +{ + AES256_init(&ctx, key); +} + +AES256Decrypt::~AES256Decrypt() +{ + memset(&ctx, 0, sizeof(ctx)); +} + +void AES256Decrypt::Decrypt(unsigned char plaintext[16], const unsigned char ciphertext[16]) const +{ + AES256_decrypt(&ctx, 1, plaintext, ciphertext); +} + + +template <typename T> +static int CBCEncrypt(const T& enc, const unsigned char iv[AES_BLOCKSIZE], const unsigned char* data, int size, bool pad, unsigned char* out) +{ + int written = 0; + int padsize = size % AES_BLOCKSIZE; + unsigned char mixed[AES_BLOCKSIZE]; + + if (!data || !size || !out) + return 0; + + if (!pad && padsize != 0) + return 0; + + memcpy(mixed, iv, AES_BLOCKSIZE); + + // Write all but the last block + while (written + AES_BLOCKSIZE <= size) { + for (int i = 0; i != AES_BLOCKSIZE; i++) + mixed[i] ^= *data++; + enc.Encrypt(out + written, mixed); + memcpy(mixed, out + written, AES_BLOCKSIZE); + written += AES_BLOCKSIZE; + } + if (pad) { + // For all that remains, pad each byte with the value of the remaining + // space. If there is none, pad by a full block. + for (int i = 0; i != padsize; i++) + mixed[i] ^= *data++; + for (int i = padsize; i != AES_BLOCKSIZE; i++) + mixed[i] ^= AES_BLOCKSIZE - padsize; + enc.Encrypt(out + written, mixed); + written += AES_BLOCKSIZE; + } + return written; +} + +template <typename T> +static int CBCDecrypt(const T& dec, const unsigned char iv[AES_BLOCKSIZE], const unsigned char* data, int size, bool pad, unsigned char* out) +{ + unsigned char padsize = 0; + int written = 0; + bool fail = false; + const unsigned char* prev = iv; + + if (!data || !size || !out) + return 0; + + if (size % AES_BLOCKSIZE != 0) + return 0; + + // Decrypt all data. Padding will be checked in the output. + while (written != size) { + dec.Decrypt(out, data + written); + for (int i = 0; i != AES_BLOCKSIZE; i++) + *out++ ^= prev[i]; + prev = data + written; + written += AES_BLOCKSIZE; + } + + // When decrypting padding, attempt to run in constant-time + if (pad) { + // If used, padding size is the value of the last decrypted byte. For + // it to be valid, It must be between 1 and AES_BLOCKSIZE. + padsize = *--out; + fail = !padsize | (padsize > AES_BLOCKSIZE); + + // If not well-formed, treat it as though there's no padding. + padsize *= !fail; + + // All padding must equal the last byte otherwise it's not well-formed + for (int i = AES_BLOCKSIZE; i != 0; i--) + fail |= ((i > AES_BLOCKSIZE - padsize) & (*out-- != padsize)); + + written -= padsize; + } + return written * !fail; +} + +AES256CBCEncrypt::AES256CBCEncrypt(const unsigned char key[AES256_KEYSIZE], const unsigned char ivIn[AES_BLOCKSIZE], bool padIn) + : enc(key), pad(padIn) +{ + memcpy(iv, ivIn, AES_BLOCKSIZE); +} + +int AES256CBCEncrypt::Encrypt(const unsigned char* data, int size, unsigned char* out) const +{ + return CBCEncrypt(enc, iv, data, size, pad, out); +} + +AES256CBCEncrypt::~AES256CBCEncrypt() +{ + memset(iv, 0, sizeof(iv)); +} + +AES256CBCDecrypt::AES256CBCDecrypt(const unsigned char key[AES256_KEYSIZE], const unsigned char ivIn[AES_BLOCKSIZE], bool padIn) + : dec(key), pad(padIn) +{ + memcpy(iv, ivIn, AES_BLOCKSIZE); +} + + +int AES256CBCDecrypt::Decrypt(const unsigned char* data, int size, unsigned char* out) const +{ + return CBCDecrypt(dec, iv, data, size, pad, out); +} + +AES256CBCDecrypt::~AES256CBCDecrypt() +{ + memset(iv, 0, sizeof(iv)); +} + +AES128CBCEncrypt::AES128CBCEncrypt(const unsigned char key[AES128_KEYSIZE], const unsigned char ivIn[AES_BLOCKSIZE], bool padIn) + : enc(key), pad(padIn) +{ + memcpy(iv, ivIn, AES_BLOCKSIZE); +} + +AES128CBCEncrypt::~AES128CBCEncrypt() +{ + memset(iv, 0, AES_BLOCKSIZE); +} + +int AES128CBCEncrypt::Encrypt(const unsigned char* data, int size, unsigned char* out) const +{ + return CBCEncrypt(enc, iv, data, size, pad, out); +} + +AES128CBCDecrypt::AES128CBCDecrypt(const unsigned char key[AES128_KEYSIZE], const unsigned char ivIn[AES_BLOCKSIZE], bool padIn) + : dec(key), pad(padIn) +{ + memcpy(iv, ivIn, AES_BLOCKSIZE); +} + +AES128CBCDecrypt::~AES128CBCDecrypt() +{ + memset(iv, 0, AES_BLOCKSIZE); +} + +int AES128CBCDecrypt::Decrypt(const unsigned char* data, int size, unsigned char* out) const +{ + return CBCDecrypt(dec, iv, data, size, pad, out); +} |