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stupidgcm: stupidChacha20poly1305.Open: batch C calls in aead_open

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Gets the decryption speed to the same level as the
encryption speed.

internal/speed$ benchstat old.txt new.txt
name                    old time/op    new time/op    delta
StupidXchacha-4          732MB/s ± 0%   740MB/s ± 0%   ~     (p=1.000 n=1+1)
StupidXchachaDecrypt-4   602MB/s ± 0%   741MB/s ± 0%   ~     (p=1.000 n=1+1)
master
Jakob Unterwurzacher 2 years ago
parent 3e27acb989
commit bf572aef88
3 changed files with 134 additions and 69 deletions
Show Stats Download Patch File Download Diff File

120
internal/stupidgcm/chacha.c
Unescape View File

@ -9,6 +9,21 @@ static void panic(const char* const msg)
__builtin_trap();
}
static const EVP_CIPHER* getEvpCipher(enum aeadType cipherId)
{
switch (cipherId) {
case aeadTypeChacha:
return EVP_chacha20_poly1305();
case aeadTypeGcm:
return EVP_aes_256_gcm();
}
panic("unknown cipherId");
return NULL;
}
// We only support 16-byte tags
static const int supportedTagLen = 16;
// https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption#Authenticated_Encryption_using_GCM_mode
int aead_seal(
const enum aeadType cipherId,
@ -23,19 +38,9 @@ int aead_seal(
unsigned char* const ciphertext,
const int ciphertextBufLen)
{
const EVP_CIPHER* evpCipher = NULL;
switch (cipherId) {
case aeadTypeChacha:
evpCipher = EVP_chacha20_poly1305();
break;
case aeadTypeGcm:
evpCipher = EVP_aes_256_gcm();
break;
default:
panic("unknown cipherId");
}
const EVP_CIPHER* evpCipher = getEvpCipher(cipherId);
// Create scratch space "context"
// Create scratch space "ctx"
EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new();
if (!ctx) {
panic("EVP_CIPHER_CTX_new failed");
@ -91,20 +96,99 @@ int aead_seal(
panic("EVP_EncryptFinal_ex: unexpected length");
}
// We only support 16-byte tags
const int tagLen = 16;
// Get MAC tag and append it to the ciphertext
if (ciphertextLen + tagLen > ciphertextBufLen) {
if (ciphertextLen + supportedTagLen > ciphertextBufLen) {
panic("tag overflows output buffer");
}
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, tagLen, ciphertext + plaintextLen) != 1) {
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, supportedTagLen, ciphertext + plaintextLen) != 1) {
panic("EVP_CTRL_AEAD_GET_TAG failed");
}
ciphertextLen += tagLen;
ciphertextLen += supportedTagLen;
// Free scratch space
EVP_CIPHER_CTX_free(ctx);
return ciphertextLen;
}
int aead_open(
const enum aeadType cipherId,
const unsigned char* const ciphertext,
const int ciphertextLen,
const unsigned char* const authData,
const int authDataLen,
unsigned char* const tag,
const int tagLen,
const unsigned char* const key,
const int keyLen,
const unsigned char* const iv,
const int ivLen,
unsigned char* const plaintext,
const int plaintextBufLen)
{
const EVP_CIPHER* evpCipher = getEvpCipher(cipherId);
// Create scratch space "ctx"
EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new();
if (!ctx) {
panic("EVP_CIPHER_CTX_new failed");
}
// Set cipher
if (EVP_DecryptInit_ex(ctx, evpCipher, NULL, NULL, NULL) != 1) {
panic("EVP_DecryptInit_ex set cipher failed");
}
// Check keyLen by trying to set it (fails if keyLen != 32)
if (EVP_CIPHER_CTX_set_key_length(ctx, keyLen) != 1) {
panic("keyLen mismatch");
}
// Set IV length so we do not depend on the default
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivLen, NULL) != 1) {
panic("EVP_CTRL_AEAD_SET_IVLEN failed");
}
// Set key and IV
if (EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv) != 1) {
panic("EVP_DecryptInit_ex set key & iv failed");
}
// Provide authentication data
int outLen = 0;
if (EVP_DecryptUpdate(ctx, NULL, &outLen, authData, authDataLen) != 1) {
panic("EVP_DecryptUpdate authData failed");
}
if (outLen != authDataLen) {
panic("EVP_DecryptUpdate authData: unexpected length");
}
// Decrypt "ciphertext" into "plaintext"
if (ciphertextLen > plaintextBufLen) {
panic("ciphertextLen overflows output buffer");
}
if (EVP_DecryptUpdate(ctx, plaintext, &outLen, ciphertext, ciphertextLen) != 1) {
panic("EVP_DecryptUpdate failed");
}
int plaintextLen = outLen;
// Check tag
if (tagLen != supportedTagLen) {
panic("unsupported tag length");
}
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, tagLen, tag) != 1) {
panic("EVP_CTRL_AEAD_SET_TAG failed");
}
if (EVP_DecryptFinal_ex(ctx, plaintext + plaintextLen, &outLen) != 1) {
// authentication failed
return -1;
}
if (outLen != 0) {
panic("EVP_EncryptFinal_ex: unexpected length");
}
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return plaintextLen;
}

15
internal/stupidgcm/chacha.h
Unescape View File

@ -15,3 +15,18 @@ int aead_seal(
const int ivLen,
unsigned char* const ciphertext,
const int ciphertextBufLen);
int aead_open(
const enum aeadType cipherId,
const unsigned char* const ciphertext,
const int ciphertextLen,
const unsigned char* const authData,
const int authDataLen,
unsigned char* const tag,
const int tagLen,
const unsigned char* const key,
const int keyLen,
const unsigned char* const iv,
const int ivLen,
unsigned char* const plaintext,
const int plaintextBufLen);

68
internal/stupidgcm/stupidchacha.go
Unescape View File

@ -6,7 +6,6 @@ import (
"crypto/cipher"
"fmt"
"log"
"unsafe"
"golang.org/x/crypto/chacha20poly1305"
)
@ -118,59 +117,26 @@ func (g *stupidChacha20poly1305) Open(dst, iv, in, authData []byte) ([]byte, err
ciphertext := in[:len(in)-tagLen]
tag := in[len(in)-tagLen:]
// https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption#Authenticated_Encryption_using_GCM_mode
// Create scratch space "context"
ctx := C.EVP_CIPHER_CTX_new()
if ctx == nil {
log.Panic("EVP_CIPHER_CTX_new failed")
}
// Set cipher to AES-256
if C.EVP_DecryptInit_ex(ctx, C.EVP_chacha20_poly1305(), nil, nil, nil) != 1 {
log.Panic("EVP_DecryptInit_ex I failed")
}
// Set key and IV
if C.EVP_DecryptInit_ex(ctx, nil, nil, (*C.uchar)(&g.key[0]), (*C.uchar)(&iv[0])) != 1 {
log.Panic("EVP_DecryptInit_ex II failed")
}
// Set expected MAC tag
if C.EVP_CIPHER_CTX_ctrl(ctx, C.EVP_CTRL_AEAD_SET_TAG, tagLen, (unsafe.Pointer)(&tag[0])) != 1 {
log.Panic("EVP_CIPHER_CTX_ctrl EVP_CTRL_AEAD_SET_TAG failed")
}
// Provide authentication data
var resultLen C.int
if C.EVP_DecryptUpdate(ctx, nil, &resultLen, (*C.uchar)(&authData[0]), C.int(len(authData))) != 1 {
log.Panic("EVP_DecryptUpdate authData failed")
}
if int(resultLen) != len(authData) {
log.Panicf("Unexpected length %d", resultLen)
}
// Decrypt "ciphertext" into "buf"
if C.EVP_DecryptUpdate(ctx, (*C.uchar)(&buf[0]), &resultLen, (*C.uchar)(&ciphertext[0]), C.int(len(ciphertext))) != 1 {
log.Panic("EVP_DecryptUpdate failed")
}
if int(resultLen) != len(ciphertext) {
log.Panicf("Unexpected length %d", resultLen)
}
// Check MAC
dummy := make([]byte, 16)
res := C.EVP_DecryptFinal_ex(ctx, (*C.uchar)(&dummy[0]), &resultLen)
if resultLen != 0 {
log.Panicf("Unexpected length %d", resultLen)
}
// Free scratch space
C.EVP_CIPHER_CTX_free(ctx)
res := int(C.aead_open(C.aeadTypeChacha,
(*C.uchar)(&ciphertext[0]),
C.int(len(ciphertext)),
(*C.uchar)(&authData[0]),
C.int(len(authData)),
(*C.uchar)(&tag[0]),
C.int(len(tag)),
(*C.uchar)(&g.key[0]),
C.int(len(g.key)),
(*C.uchar)(&iv[0]),
C.int(len(iv)),
(*C.uchar)(&buf[0]),
C.int(len(buf))))
if res != 1 {
if res < 0 {
return nil, ErrAuth
}
if res != outLen {
log.Panicf("unexpected length %d", res)
}
if inplace {
return dst[:len(dst)+outLen], nil

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