Python 进行RSA私钥加密，公钥解密

使用M2Crypto库

需要安装M2Crypto库

1. # -*- coding: UTF-8 -*-
2. import M2Crypto
3. from Crypto.PublicKey import RSA
4. import base64
5. import sys
7. #私钥加密，公钥解密
8. def pri_encrypt(msg, file_name):
9. rsa_pri = M2Crypto.RSA.load_key(file_name)
10. ctxt_pri = rsa_pri.private_encrypt(msg, M2Crypto.RSA.pkcs1_padding) #这里的方法选择加密填充方式，所以在解密的时候 要对应。
11. ctxt64_pri = ctxt_pri.encode('base64') #密文是base64 方便保存 encode成str
12. print ('密文:%s'% ctxt64_pri)
13. return ctxt64_pri
15. def pub_decrypt_with_pubkeyfile(msg, file_name):
16. rsa_pub = M2Crypto.RSA.load_pub_key(file_name)
17. pub_decrypt(msg, rsa_pub)
19. def pub_decrypt_with_pubkeystr(msg, pub_key):
20. #将pub_key转成bio对象,再将bio对象转换成公钥对象
21. bio = M2Crypto.BIO.MemoryBuffer(pub_key)
22. rsa_pub = M2Crypto.RSA.load_pub_key_bio(bio)
23. pub_decrypt(msg, rsa_pub)
25. def pub_decrypt(msg, rsa_pub):
26. ctxt_pri = msg.decode("base64") # 先将str转成base64
27. maxlength = 128
28. output = ''
29. while ctxt_pri:
30. input = ctxt_pri[:128]
31. ctxt_pri = ctxt_pri[128:]
32. out = rsa_pub.public_decrypt(input, M2Crypto.RSA.pkcs1_padding) #解密
33. output = output + out
34. print('明文:%s'% output)
36. if __name__ == "__main__":
37. prikey_file = './rsa/rsa_private_key.pem'
38. pubkey_file = './rsa/rsa_public_key.pem'
39. msg = 'Test String.'
40. primsg = pri_encrypt(msg, prikey_file)
41. pub_decrypt(primsg, pubkey_file)

---

使用C语言的动态库

decrypt.c

1. #include
2. #include
3. #include
4. #include
5. #include
6. #include
8. void decrypt(char *pristr, char *pubkey, int padding, char *pub_str)
9. {
10. BIO *bp;
11. EVP_PKEY *pkey;
12. int crypted_len, n;
13. size_t data_len;
14. char *data, *dest_p, *p, *last, *decrypt_buf, *dest;
15. char buf[128];
17. bp = BIO_new_mem_buf((void *)pubkey, -1);
18. pkey = PEM_read_bio_PUBKEY(bp, NULL, NULL, NULL);
19. BIO_free(bp);
21. if (!pkey) {
22. fprintf(stderr, "get public key error\n");
23. return;
24. }
26. crypted_len = EVP_PKEY_size(pkey);
27. decrypt_buf = malloc(crypted_len + 1);
28. if (!decrypt_buf) {
29. fprintf(stderr, "decrypt_buf, malloc error\n");
30. return;
31. }
33. base64_decode(pristr, (unsigned char **)&data, &data_len);
35. dest = malloc(data_len);
36. if (!dest) {
37. fprintf(stderr, "dest, malloc error\n");
38. free(decrypt_buf);
39. return;
40. }
41. dest_p = dest;
43. p = data;
44. last = data + data_len;
46. do {
47. n = last - p;
48. if (n > 128) {
49. n = 128;
50. }
52. bzero(buf, sizeof(buf));
53. bzero(decrypt_buf, sizeof(decrypt_buf));
54. memcpy(buf, p, n);
55. p += n;
57. crypted_len = RSA_public_decrypt(n, (unsigned char *)buf, decrypt_buf, pkey->pkey.rsa, padding);
58. if (crypted_len != -1) {
59. memcpy(dest_p, decrypt_buf, crypted_len);
60. dest_p += crypted_len;
61. }
62. } while (last - p > 0);
64. *dest_p = 0;
65. strcpy(pub_str, dest);
66. free(decrypt_buf);
67. free(dest);
68. free(data);
69. }
72. size_t calc_decode_len(const char* b64input) {
73. size_t len = strlen(b64input), padding = 0;
75. if (b64input[len - 1] == '=' && b64input[len - 2] == '=') {
76. padding = 2;
77. } else if (b64input[len - 1] == '=') {
78. padding = 1;
79. }
81. return (size_t) len * 0.75 - padding;
82. }
84. int base64_decode(char *b64message, unsigned char **buffer, size_t *len) {
85. BIO *bio, *b64;
87. int decode_len = calc_decode_len(b64message);
88. *buffer = malloc(decode_len);
89. if (!*buffer) {
90. fprintf(stderr, "buffer, malloc error\n");
91. return -1;
92. }
94. bio = BIO_new_mem_buf(b64message, -1);
95. b64 = BIO_new(BIO_f_base64());
96. bio = BIO_push(b64, bio);
98. BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);
99. *len = BIO_read(bio, *buffer, strlen(b64message));
100. BIO_free_all(bio);
102. if (*len != decode_len) {
103. return -1;
104. }
106. return 0;
107. }

decrypt.h

1. #ifndef __DECRYPT_H__
2. #define __DECRYPT_H__
4. #include
5. #include
6. #include
7. #include
8. #include
9. #include
11. void decrypt(char* pristr, char* pubkey, int padding, char* pubstr);
13. #endif

编译，生成一个动态库文件

1. gcc -Wall -fpic -shared -lcrypto decrypt.c -o libdec.so

写一个测试文件进行测试，main.c

1. #include "decrypt.h"
2. #include
4. int main()
5. {
6. //公钥
7. char *pkey_str = "-----BEGIN PUBLIC KEY-----\nMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2kcrRvxURhFijDoPpqZ/IgPlA\ngppkKrek6wSrua1zBiGTwHI2f+YCa5vC1JEiIi9uw4srS0OSCB6kY3bP2DGJagBo\nEgj/rYAGjtYJxJrEiTxVs5/GfPuQBYmU0XAtPXFzciZy446VPJLHMPnmTALmIOR5\nDddd1Zklod9IQBMjjwIDAQAB\n-----END PUBLIC KEY-----";
9. //用私钥加密过的字符串
10. char *pri_str = "YFSGlJTpNYakrZuZqZ55dcA5mVUb/JQBr3hdDjODsAVSdoVVytIagk9Wt0CD/uX+7jGL9pqev8/u0I0ZBKEmz5huXp8TdZSnskCZ7GTeHNW0VPJcW8OcBxAValA0jQSv2mBP+tc1r6mdvf66GEzhvgBfTnp3Sp7V3dijJ9bNstIDyrGm/BlByhcMr3UqXjTFJaui6t5TxvZhCuSV9sg+xVVA+sR3uFI78b5lKomg5Vu31EBZvXASlFfaOc4StltRUH2aSiRqjnbXe8dlRZO0Ih44htYs2QfehzeQnPHtTwNHUvtVIVcIdI/7j9yfy5es13QeIgfKghY/ENUnB2V7iA==";
12. char decrypted_buf[10240];
13. decrypt(pri_str, pkey_str, 1, decrypted_buf);
14. printf("%s", decrypted_buf);
15. return 0;
16. }

编译，测试：

1. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:'pwd'
2. gcc main.c -o test -L./ -ldec
3. ./test
4. [zhangshibo@tuyoo so_test]${"order_id_com":"2013061805870589","amount":"0.10","account":"test","order_id":"2013061800002115","result":"success","user_id":"0"}

---

在python中使用libdec.so 
注意，需要安装cffi，然后用pypy运行 
test.py

1. import os
2. from cffi import FFI
3. path = os.path.split(os.path.realpath(__file__))[0]
4. ffi = FFI()
5. #引入动态库
6. lib = ffi.dlopen(path + "/libdec.so")
7. print('Loaded lib {0}'.format(lib))
8. #函数声明，类似于C的.h文件
9. ffi.cdef(
10. '''
11. void decrypt(char* pristr, char* pubkey, int padding, char* pubstr);
12. int printf(const char* format, ...);
13. '''
14. )
15. #公钥
16. pkey_str = '''-----BEGIN PUBLIC KEY-----
17. MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2kcrRvxURhFijDoPpqZ/IgPlA
18. gppkKrek6wSrua1zBiGTwHI2f+YCa5vC1JEiIi9uw4srS0OSCB6kY3bP2DGJagBo
19. Egj/rYAGjtYJxJrEiTxVs5/GfPuQBYmU0XAtPXFzciZy446VPJLHMPnmTALmIOR5
20. Dddd1Zklod9IQBMjjwIDAQAB
21. -----END PUBLIC KEY-----'''
23. #用私钥加密过的字符串
24. pri_str = "klzAd6Qu87M/0GdkmmeJbyk/NKuIIRS/M/4GpckMNfe4jwjBc9w38LExpYVvJZ5RKkr2y9Wuj6cZsThqAM0ZDcFZ2Ew2csRZlMnc9kD/yqHHMb0fb6KL3g7DZ3sRAhAIT2MkTDHOVKctxrc5Qcn8Ie2IX1Xgz7G+yvn0j1VYc3xGUbbCxxPjb3MTuDUDFbElPNq98dQufrcFUBsXwVdQJv6+GwE+7N/IJffPA6TNv3aB+AUe7sc/lbKOywxCSb0+rxPkb0mcT6q5O0S1bRIvZqtxQJn0HydqmFYPBYr9X2lzkgGIwZL8oX6vb2YVNHRPoCxKh+10TewAOOlUggbTfA=="
26. #申请C风格的数组
27. pub_str = ffi.new("char[]", 10240)
28. lib.decrypt(pri_str, pkey_str, 1, pub_str)
30. print pub_str
31. lib.printf("%s\n", pub_str)
33. #转换成Python可用的字符串
34. pystr = ffi.string(pub_str)
35. print pystr