原理簡述

chacha20-poly1305 是帶有關聯數據的認證加密（AEAD）AEAD是一種能夠同時保證數據的保密性、 完整性和真實性的一種加密模式。
通常使用除了明文以外，會把包頭的地址和端口等信息放進去一起做完整性校驗。

chacha20 是流加密算法。
poly1305 是完整性校驗是算法，即根據輸入（加密數據和關聯數據）輸出16字節的認證標簽。

使用方法

加密

輸入項：

輸入項長度(Bytes)說明

key	32	共享秘鑰
iv	12	干擾項，每次不同
AAD	N	關聯數據
plaintext	N	待加密數據明文

輸出項：

輸出項長度(Bytes)說明

ciphertext	N	加密后的密文，長度與原始明文一致
TAG	16	認證標簽

通常將TAG接在ciphertext密文之后。

解密

輸入項：

輸入項長度(Bytes)說明

key	32	共享秘鑰
iv	12	干擾項，每次不同
AAD	N	關聯數據
ciphertext	N	待加密數據明文
TAG	16	認證標簽

輸出項：

輸出項長度(Bytes)說明

plaintext	N	原始明文
result	1	完整性檢查結果（1成功，0失敗）

參數關聯

key + iv + plaintext ===> ciphertext
ciphertext + AAD ===> TAG

AAD只參與完整性驗證，不參與加密。

代碼實例

代碼剛驗證完，沒整理，湊合看，嘻嘻。

int chachapoly_test(void) {/* Key 共享秘鑰 */unsigned char skey2[32] = {0x2e,0xff,0xe4,0x85,0x1e,0x23,0x72,0xef,0x5c,0x44,0x14,0x75,0x61,0xd8,0xf0,0xa3,0xde,0x91,0x09,0x00,0x24,0x03,0x51,0x3c,0xf2,0xf6,0x6d,0x16,0xbd,0x78,0xd2,0x63};int ret = 0;EVP_CIPHER_CTX* ctx = NULL;EVP_CIPHER_CTX* dctx = NULL;/* 干擾項 iv */unsigned char iv[12] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b};/* 外部關聯數據 AAD */unsigned char aad[128] = {0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1f,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1f,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1f,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1f,0x20,0x21,0x22,0x23,0x24,0x25,0x26};unsigned char ciphertext[1024] = {0};unsigned char res[1024] = {0};/* 原始明文 plaintext */unsigned char msg[] = "0123456789abcdefghijklmnopqrstuvwxyz";ctx = EVP_CIPHER_CTX_new();ret = EVP_EncryptInit_ex(ctx, EVP_chacha20_poly1305(), NULL, skey2, iv);printf("EncryptInit ret: %d\n", ret);int outlen, finallen, reslen;/* 加密輸入 ADD */ret = EVP_EncryptUpdate(ctx, NULL, &outlen, aad, 32);ret = EVP_EncryptUpdate(ctx, NULL, &outlen, aad+64, 32);printf("Ret: %d Update AAD len: %d\n", ret, outlen);/* 加密原始數據 */ret = EVP_EncryptUpdate(ctx, ciphertext, &outlen, msg, 37);printf("Ret: %d Update len: %u\n", ret, outlen);print_strhex(ciphertext, outlen);ret = EVP_EncryptFinal(ctx, ciphertext, &finallen);printf("Ret: %d Final len: %u\n", ret, finallen);outlen += finallen;//print_strhex(ciphertext, outlen);/* 生成認證標簽TAG */unsigned char* tag_data = ciphertext + outlen;EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, 16, tag_data);outlen += 16;print_strhex(ciphertext, outlen);dctx = EVP_CIPHER_CTX_new();//iv[0] = 0x0f;//skey2[0] = 0xff;//tag_data[0] = 0x01;//aad[0] = 0x01;ret = EVP_DecryptInit_ex(dctx, EVP_chacha20_poly1305(), NULL, skey2, iv);printf("DecryptInit ret: %d\n", ret);ret = EVP_CIPHER_CTX_ctrl(dctx, EVP_CTRL_GCM_SET_TAG, 16, tag_data);printf("Ret: %d CTX set TAG\n", ret);ret = EVP_DecryptUpdate(dctx, NULL, &reslen, aad, 32);ret = EVP_DecryptUpdate(dctx, NULL, &reslen, aad+64, 32);printf("Ret: %d Update AAD len: %d\n", ret, reslen);ret = EVP_DecryptUpdate(dctx, res, &reslen, ciphertext, outlen - 16);printf("Ret: %d DecryUpdate once len: %u\n", ret, reslen);int totallen = reslen;ret = EVP_DecryptFinal(dctx, res, &reslen);printf("Ret: %d DecryptFinal len: %u\n", ret, reslen);//reslen += finallen;//print_strhex(res, totallen);printf("%s\n", res); }

總結

以上是生活随笔為你收集整理的Openssl中chacha20-poly1305的使用的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。