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Finish encrypt operation.

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This commit is contained in:
JoelKatz
2012-04-04 18:11:24 -07:00
parent 65c3059647
commit 18fc5bd93c
1 changed files with 47 additions and 16 deletions
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63
src/ECIES.cpp
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@@ -4,6 +4,7 @@
#include <openssl/ecdsa.h> #include <openssl/ecdsa.h>
#include <openssl/pem.h> #include <openssl/pem.h>
#include <openssl/hmac.h> #include <openssl/hmac.h>
#include <openssl/rand.h>
#include <vector> #include <vector>
#include <cassert> #include <cassert>
@@ -43,10 +44,9 @@ std::vector<unsigned char> CKey::getECIESSecret(CKey& otherKey)
return ret; return ret;
} }
// Our ciphertext is all encrypted. The encrypted data decodes as follows: // Our ciphertext is all encrypted except the IV. The encrypted data decodes as follows:
// 1) 256-bits of SHA-512 HMAC of original plaintext // 1) 256-bits of SHA-512 HMAC of original plaintext
// 2) 128-bit IV // 2) Original plaintext
// 3) Original plaintext
static uint256 makeHMAC(const std::vector<unsigned char>& secret, const std::vector<unsigned char> data) static uint256 makeHMAC(const std::vector<unsigned char>& secret, const std::vector<unsigned char> data)
{ {
@@ -80,8 +80,6 @@ static uint256 makeHMAC(const std::vector<unsigned char>& secret, const std::vec
return ret; return ret;
} }
#if 0
std::vector<unsigned char> CKey::encryptECIES(CKey& otherKey, const std::vector<unsigned char>& plaintext) std::vector<unsigned char> CKey::encryptECIES(CKey& otherKey, const std::vector<unsigned char>& plaintext)
{ {
std::vector<unsigned char> secret=getECIESSecret(otherKey); std::vector<unsigned char> secret=getECIESSecret(otherKey);
@@ -89,26 +87,61 @@ std::vector<unsigned char> CKey::encryptECIES(CKey& otherKey, const std::vector<
uint256 hmac=makeHMAC(secret, plaintext); uint256 hmac=makeHMAC(secret, plaintext);
uint128 iv; uint128 iv;
if(RAND_bytes((unsigned char *) iv.begin(), 128/8) != 1) if(RAND_bytes(static_cast<unsigned char *>(iv.begin()), 128/8) != 1)
throw std::runtime_error("insufficient entropy"); throw std::runtime_error("insufficient entropy");
ECP_CIPHER_CTX ctx; EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx); EVP_CIPHER_CTX_init(&ctx);
if (EVP_EncryptInit_ex(&ctx, EVP_AES_128_cbc(), NULL, key, iv) != 1) if (EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
&(secret.front()), static_cast<unsigned char *>(iv.begin())) != 1)
{ {
EVP_CIPHER_CTX_cleanup(&ctx); EVP_CIPHER_CTX_cleanup(&ctx);
throw std::runtime_error("init cipher ctx"); throw std::runtime_error("init cipher ctx");
} }
EVP_EncryptUpdate std::vector<unsigned char> out(plaintext.size() + (256/8) + (512/8) + 48, 0);
EVP_EncryptUpdate int len=0, bytesWritten;
EVP_EncryptUpdate
// output 256-bit IV
ECP_EncryptFinal_ex memcpy(&(out.front()), iv.begin(), 32);
len=32;
// Encrypt/output 512-bit HMAC
bytesWritten=out.capacity()-len;
assert(bytesWritten>0);
if(EVP_EncryptUpdate(&ctx, &(out.front())+len, &bytesWritten, hmac.begin(), 64) < 0)
{
EVP_CIPHER_CTX_cleanup(&ctx);
throw std::runtime_error("");
}
len+=bytesWritten;
// encrypt/output plaintext
bytesWritten=out.capacity()-len;
assert(bytesWritten>0);
if(EVP_EncryptUpdate(&ctx, &(out.front())+len, &bytesWritten, &(plaintext.front()), plaintext.size()) < 0)
{
EVP_CIPHER_CTX_cleanup(&ctx);
throw std::runtime_error("");
}
len+=bytesWritten;
// finalize
bytesWritten=out.capacity()-len;
if(EVP_EncryptFinal_ex(&ctx, &(out.front())+len, &bytesWritten) < 0)
{
EVP_CIPHER_CTX_cleanup(&ctx);
throw std::runtime_error("");
}
len+=bytesWritten;
out.resize(len);
EVP_CIPHER_CTX_cleanup(&ctx);
return out;
} }
std::vector<unsigned char> CKey::decryptECIES(CKey& otherKey, const std::Vector<unsigned char>& ciphertext) std::vector<unsigned char> CKey::decryptECIES(CKey& otherKey, const std::vector<unsigned char>& ciphertext)
{ {
std::vector<unsigned char> secret=getECIESSecret(otherKey); std::vector<unsigned char> secret=getECIESSecret(otherKey);
@@ -122,6 +155,4 @@ std::vector<unsigned char> CKey::decryptECIES(CKey& otherKey, const std::Vector<
} }
#endif
// vim:ts=4 // vim:ts=4