func (a *AESDecrypter) XORKeyStream(dst, src []byte) { var out_len int c_out_len := (*C.int)(unsafe.Pointer(&out_len)) c_in := (*C.uint8_t)(unsafe.Pointer(&src[0])) c_out := (*C.uint8_t)(unsafe.Pointer(&dst[0])) C.EVP_DecryptUpdate(a.ctx, c_out, c_out_len, c_in, (C.int)(len(dst))) }
func (ctx *decryptionCipherCtx) DecryptUpdate(input []byte) ([]byte, error) { outbuf := make([]byte, len(input)+ctx.BlockSize()) outlen := C.int(len(outbuf)) res := C.EVP_DecryptUpdate(ctx.ctx, (*C.uchar)(&outbuf[0]), &outlen, (*C.uchar)(&input[0]), C.int(len(input))) if res != 1 { return nil, fmt.Errorf("failed to decrypt [result %d]", res) } return outbuf[:outlen], nil }
func (ctx *authDecryptionCipherCtx) ExtraData(aad []byte) error { if aad == nil { return nil } var outlen C.int if 1 != C.EVP_DecryptUpdate(ctx.ctx, nil, &outlen, (*C.uchar)(&aad[0]), C.int(len(aad))) { return errors.New("failed to add additional authenticated data") } return nil }
func (self *CipherCtx) DecryptUpdate(dst []byte, src []byte) (int, error) { dstbuf := (*C.uchar)(unsafe.Pointer(&dst[0])) var dstlen C.int srcbuf := (*C.uchar)(unsafe.Pointer(&src[0])) srclen := len(src) ret := C.EVP_DecryptUpdate(self.evp_cipher_ctx, dstbuf, &dstlen, srcbuf, C.int(srclen)) if int(ret) != 1 { return 0, errors.New("problem decrypting") } return int(dstlen), nil }
func (ctx *CipherCtx) DecryptUpdate(dst []byte, src []byte) (int, error) { dstbuf := (*C.uchar)(unsafe.Pointer(&dst[0])) var dstlen C.int srcbuf := (*C.uchar)(unsafe.Pointer(&src[0])) srclen := len(src) ret := C.EVP_DecryptUpdate(ctx.evp_cipher_ctx, dstbuf, &dstlen, srcbuf, C.int(srclen)) if int(ret) != 1 { //return 0, ErrProblemDecrypting return 0, sslerr.Error() } return int(dstlen), nil }
// Open decrypts "in" using "iv" and "authData" and append the result to "dst" func (g stupidGCM) Open(dst, iv, in, authData []byte) ([]byte, error) { if len(iv) != ivLen { log.Panicf("Only %d-byte IVs are supported", ivLen) } if len(in) <= tagLen { log.Panic("Input data too short") } buf := make([]byte, len(in)-tagLen) 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_aes_256_gcm(), nil, nil, nil) != 1 { log.Panic("EVP_DecryptInit_ex I failed") } // Use 16-byte IV if C.EVP_CIPHER_CTX_ctrl(ctx, C.EVP_CTRL_GCM_SET_IVLEN, ivLen, nil) != 1 { log.Panic("EVP_CIPHER_CTX_ctrl EVP_CTRL_GCM_SET_IVLEN 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 GMAC tag if C.EVP_CIPHER_CTX_ctrl(ctx, C.EVP_CTRL_GCM_SET_TAG, tagLen, (unsafe.Pointer)(&tag[0])) != 1 { log.Panic("EVP_CIPHER_CTX_ctrl 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 GMAC 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) if res != 1 { return nil, fmt.Errorf("stupidgcm: message authentication failed") } return append(dst, buf...), nil }