Linux C/C++ Openssl RSA Encrypt/Decrypt(加密/解密) 简单示例教程

PEM文件有以下格式

1. PEM私钥文件格式

   -----BEGIN RSA PRIVATE KEY----------END RSA PRIVATE KEY-----

   生成该密钥的Linux命令：OpenSSL>genrsa -out privateKey.pem 1024
   读取该密钥的Linux Openssl API 函数文件读取：
   RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **rsa, pem_password_cb *cb, void *u)
   读取该密钥的Linux Openssl API 函数内存读取：
   RSA *PEM_read_bio_RSAPrivateKey(BIO *bio, RSA **rsa, pem_password_cb *cb, void *u)
   
   
   
2. PEM私钥文件格式(经过口令加密)
   

   -----BEGIN RSA PRIVATE KEY-----Proc-Type: 4,ENCRYPTEDDEK-Info: DES-EDE3-CBC,FCD22C6C17CF034C-----END RSA PRIVATE KEY-----

   生成该密钥的Linux命令：OpenSSL>genrsa -des3 -out privateKey.pem 1024
   enter后会要求输入口令(最少四位)
   读取该密钥的Linux Openssl API 函数文件读取：
   RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **rsa, pem_password_cb *cb, void *u)
   读取该密钥的Linux Openssl API 函数内存读取：
   RSA *PEM_read_bio_RSAPrivateKey(BIO *bio, RSA **rsa, pem_password_cb *cb, void *u)
   
   
3. PEM公钥文件格式
   

   -----BEGIN PUBLIC KEY----------END PUBLIC KEY-----

   生成该密钥的Linux命令：OpenSSL>rsa -in privateKey.pem -pubout -out publicKey.pem
   读取该密钥的Linux Openssl API 函数文件读取：
   RSA *PEM_read_RSA_PUBKEY(FILE *fp, RSA **rsa, pem_password_cb *cb, void *u)
   读取该密钥的Linux Openssl API 函数内存读取：
   RSA *PEM_read_bio_PUBKEY(BIO *bio, RSA **rsa, pem_password_cb *cb, void *u)
   
   
4. PEM RSAPublicKey公钥文件格式
   

   -----BEGIN RSA PUBLIC KEY----------END RSA PUBLIC KEY-----

   生成该密钥的Linux命令：OpenSSL>rsa -in privateKey.pem -RSAPublicKey_out -out publicKey.pem
   读取该密钥的Linux Openssl API 函数文件读取：
   RSA *PEM_read_RSAPublicKey(FILE *fp, RSA **rsa, pem_password_cb *cb, void *u)
   读取该密钥的Linux Openssl API 函数内存读取：
   RSA *PEM_read_bio_RSAPublicKey(BIO *bio, RSA **rsa, pem_password_cb *cb, void *u)
   
   
5. RSA加密API
   int RSA_public_encrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa, int padding)
   参数说明：
   flen: 填充方式加密长度
   from: 要加密信息
   to: 加密后的信息
   padding: 填充方式( RSA_PKCS1_PADDING ，RSA_PKCS1_OAEP_PADDING，RSA_SSLV23_PADDING，RSA_NO_PADDING)
   (注：flen会根据不同的填充方式大小会有变化参考)
   
   
6. RSA解密API
   int RSA_private_decrypt(int flen, unsigned char *from, unsigned char *to, RSA *rsa, int padding)
   参数说明：
   flen: 解密密钥长度
   from: 要解密信息
   to: 解密后的信息
   padding: 填充方式( RSA_PKCS1_PADDING ，RSA_PKCS1_OAEP_PADDING，RSA_SSLV23_PADDING，RSA_NO_PADDING)
   (注：flen填写的是密钥长度可用RSA_size(rsa)函数得到)
   
   
7. RSA编程示例(PEM文件方式)
   

   #include <openssl/rsa.h>#include <openssl/pem.h>#define PUBLICKEY "publicKey.pem"#define PRIVATEKEY "privateKey.pem"#define PASS "8888" //口令int main(int argc, char *argv[]){FILE *fp = NULL;RSA *publicRsa = NULL;RSA *privateRsa = NULL;if ((fp = fopen(PUBLICKEY, "r")) == NULL) {printf("public key path error\n");return -1;}    if ((publicRsa = PEM_read_RSA_PUBKEY(fp, NULL, NULL, NULL)) == NULL) {printf("PEM_read_RSA_PUBKEY error\n");return -1;}fclose(fp);if ((fp = fopen(PRIVATEKEY, "r")) == NULL) {printf("private key path error\n");return -1;}OpenSSL_add_all_algorithms();//密钥有经过口令加密需要这个函数if ((privateRsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, (char *)PASS)) == NULL) {printf("PEM_read_RSAPrivateKey error\n");return NULL;}fclose(fp);unsigned char *source = (unsigned char *)"123456789";int rsa_len = RSA_size(publicRsa); unsigned char *encryptMsg = (unsigned char *)malloc(rsa_len);memset(encryptMsg, 0, rsa_len); int len = rsa_len - 11; if (RSA_public_encrypt(len, source, encryptMsg, publicRsa, RSA_PKCS1_PADDING) < 0)printf("RSA_public_encrypt error\n");else {rsa_len = RSA_size(privateRsa);unsigned char *decryptMsg = (unsigned char *)malloc(rsa_len);memset(decryptMsg, 0, rsa_len);    int mun =  RSA_private_decrypt(rsa_len, encryptMsg, decryptMsg, privateRsa, RSA_PKCS1_PADDING); if ( mun < 0)printf("RSA_private_decrypt error\n");elseprintf("RSA_private_decrypt %s\n", decryptMsg);}RSA_free(publicRsa);RSA_free(privateRsa);return 0;}

   
   
   
   
   
8. RSA编程示例(PEM内存方式)
   

   #include <cstdio>#include <cstring>#include <openssl/rsa.h>#include <openssl/pem.h>const char *publicKey = "-----BEGIN PUBLIC KEY-----\n\MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDnal1HozHfmZ3B1TITmbjCNKOs\n\49S+urgJ2P0/T36qN5w+r1jGhZKr54QDI5oXEk+9arlKxDW8kufwGjaTV3i3hyGS\n\jYv4wNXhPeZAyAQ1vlloLMT6oA0PKe9/l8+mAr1QPEW9fMixAc/0UzPVospjkpfr\n\YULcrKcH2Oaou5DZ0QIDAQAB\n\-----END PUBLIC KEY-----";const char *privateKey = "-----BEGIN RSA PRIVATE KEY-----\n\Proc-Type: 4,ENCRYPTED\n\DEK-Info: DES-EDE3-CBC,DF3BD9835CA1186D\n\\n\pomWi9/hjscwDDzH5CEpcj8nCumOQpl/2Gk2YynA47qfhxt12glNjgWl5Eaevk2L\n\bG1t85sPqEvYxAe+ZxZdP6fot+sAg4SUUwSvBMwa7s3XjVhHjf/+hOIjb0skHvp/\n\p0eOoUgytX7FrNNYEpUFI+eiPob79fgQMq/rypGJ//G6GXLMYixWw2+PyPa1x2PQ\n\WdBaTpZK3gmDqmu6jR3ieKOahVVO4fEGB5etvB5i1aAh0mT4Wu+ejv2LgIRr2xor\n\r8LkQZvI/TryZ0sNLe7LlC1bz/Hw8hLBDPprhWaUcSEk6MMgh3LKA2y/pGpFdIYN\n\Ncj/c+YqEsO+I0KOtPQ1fXlXd1hH1H1rkJxuaNanF0UInUuupV3fP+7cvmfyHM4m\n\aix8ROt1/Ghau41JDZGYmwk2qgKjUw4zz3eYOMQKl6row3pzhDxbvoMp0Qvfje1J\n\RYpKMy8skG9pY1l4i1CC98aESC2a7FzjUNcY3f5Jt+QznO15xXxxuJZ8+xNqtIh2\n\U348rlrQ8OxS1YBJCr+wjesdBdQAiY6X1YB9tljPs7AhlTLo78pHtQac521xOA8j\n\IcbfkuTIrMIwYBOtM6SJHkB1TgPdPWx+haEy79Ct2yDnvpPqOiFz8i8TG8AQY53l\n\5xKxxJ9CmPqw+Ua3DAWPaxAMaJFteRbl5Lv/2MvxV9Mu3T0W4B3ij+Gg5aw81v5Y\n\KTH2KxruYAF5Q70QG8CAR8Vkvdczw940y8nb9pvcixmqYcaaeM9DLaTbycn/AeCt\n\3UM0R0vvu039Ix5uhXUtVMjhTeUnvNObwEcKM8Grv1oPV3zmTJ5hJg==\n\-----END RSA PRIVATE KEY-----";#define PASS "8888" //口令int main(int argc, char *argv[]){BIO *bio = NULL;RSA *publicRsa = NULL;RSA *privateRsa = NULL;if ((bio = BIO_new_mem_buf((void *)publicKey, -1)) == NULL){printf("BIO_new_mem_buf publicKey error\n");return -1;}    if ((publicRsa = PEM_read_bio_RSA_PUBKEY(bio, NULL, NULL, NULL)) == NULL) {printf("PEM_read_bio_RSA_PUBKEY error\n");return -1;}BIO_free_all(bio);if ((bio = BIO_new_mem_buf((void *)privateKey, -1)) == NULL){printf("BIO_new_mem_buf privateKey error\n");return -1;}OpenSSL_add_all_algorithms();//密钥有经过口令加密需要这个函数if ((privateRsa = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, (char *)PASS)) == NULL) {printf("PEM_read_RSAPrivateKey error\n");return NULL;}BIO_free_all(bio);unsigned char *source = (unsigned char *)"123456789";int rsa_len = RSA_size(publicRsa); unsigned char *encryptMsg = (unsigned char *)malloc(rsa_len);memset(encryptMsg, 0, rsa_len); int len = rsa_len - 11; if (RSA_public_encrypt(len, source, encryptMsg, publicRsa, RSA_PKCS1_PADDING) < 0)printf("RSA_public_encrypt error\n");else {rsa_len = RSA_size(privateRsa);unsigned char *decryptMsg = (unsigned char *)malloc(rsa_len);memset(decryptMsg, 0, rsa_len);    int mun =  RSA_private_decrypt(rsa_len, encryptMsg, decryptMsg, privateRsa, RSA_PKCS1_PADDING); if ( mun < 0)printf("RSA_private_decrypt error\n");elseprintf("RSA_private_decrypt %s\n", decryptMsg);}RSA_free(publicRsa);RSA_free(privateRsa);return 0;}

   
   
   
9. RSA编程示例(PEM文件方式多线程测试样例)
   

   #include <cstdio>#include <cstring>#include <pthread.h>#include <openssl/rsa.h>#include <openssl/pem.h>#include <openssl/err.h>#define PRIKEY "prikey.pem"#define PUBKEY "pubkey.pem"RSA *publicRsa = NULL;RSA *privateRsa = NULL;void* rsaThreadOne(void* param){unsigned char *source = (unsigned char *)param;int rsa_len = RSA_size(publicRsa); unsigned char *encryptMsg = (unsigned char *)malloc(rsa_len);memset(encryptMsg, 0, rsa_len); int len = rsa_len - 11; if (RSA_public_encrypt(len, source, encryptMsg, publicRsa, RSA_PKCS1_PADDING) < 0){printf("rsaThreadOne RSA_public_encrypt error\n");return 0;}rsa_len = RSA_size(privateRsa);unsigned char *decryptMsg = (unsigned char *)malloc(rsa_len);memset(decryptMsg, 0, rsa_len);    int mun =  RSA_private_decrypt(rsa_len, encryptMsg, decryptMsg, privateRsa, RSA_PKCS1_PADDING); if ( mun < 0){printf("rsaThreadOne RSA_private_decrypt error\n");return 0;}else {printf("rsaThreadOne %s\n", decryptMsg);}return 0;}void* rsaThreadTwo(void* param){unsigned char *source = (unsigned char *)param;int rsa_len = RSA_size(publicRsa); unsigned char *encryptMsg = (unsigned char *)malloc(rsa_len);memset(encryptMsg, 0, rsa_len); int len = rsa_len - 11; if (RSA_public_encrypt(len, source, encryptMsg, publicRsa, RSA_PKCS1_PADDING) < 0){printf("rsaThreadTwo RSA_public_encrypt error\n");return 0;}rsa_len = RSA_size(privateRsa);unsigned char *decryptMsg = (unsigned char *)malloc(rsa_len);memset(decryptMsg, 0, rsa_len);    int mun =  RSA_private_decrypt(rsa_len, encryptMsg, decryptMsg, privateRsa, RSA_PKCS1_PADDING); if ( mun < 0){printf("rsaThreadTwo RSA_private_decrypt error\n");return 0;}else {printf("rsaThreadTwo %s\n", decryptMsg);}return 0;}int main(int argc, char *argv[]){FILE *fp = NULL;if ((fp = fopen(PUBKEY, "r")) == NULL) {printf("pubkey_path error\n");return -1;}    if ((publicRsa = PEM_read_RSA_PUBKEY(fp, NULL, NULL, NULL)) == NULL) {        printf("PEM_read_RSA_PUBKEY error\n");        return -1;}fclose(fp);if ((fp = fopen(PRIKEY, "r")) == NULL) {printf("prikey_path error\n");return -1;    }OpenSSL_add_all_algorithms();//密钥有经过口令加密需要这个函数if ((privateRsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, (char *)"8888")) == NULL) {printf("PEM_read_RSAPrivateKey error\n");return NULL;}fclose(fp);pthread_t tid1 ;pthread_t tid2 ;pthread_create(&tid1, NULL, rsaThreadOne, (void *)"123456789");pthread_create(&tid2, NULL, rsaThreadTwo, (void *)"987654321");        pthread_join(tid1,NULL);pthread_join(tid2,NULL); return 0;}

   
   
   
10. 相应参考文章、文档
    嗨！大佟！博客
    wjlkoorey的博客
    需要翻墙才能访问的openssl github