如何将公钥从JWK转换为OpenSSL的PEM？

Question

RFC中有一个RSA密钥:

https://tools.ietf.org/html/rfc7516#appendix-A.1

 {"kty":"RSA",
  "n":"oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUW
       cJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S
       psk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2a
       sbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMS
       tPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2dj
       YgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw",
  "e":"AQAB",
  "d":"kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5N
       WV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD9
       3Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghk
       qDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vl
       t3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSnd
       VTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ",
  "p":"1r52Xk46c-LsfB5P442p7atdPUrxQSy4mti_tZI3Mgf2EuFVbUoDBvaRQ-
       SWxkbkmoEzL7JXroSBjSrK3YIQgYdMgyAEPTPjXv_hI2_1eTSPVZfzL0lf
       fNn03IXqWF5MDFuoUYE0hzb2vhrlN_rKrbfDIwUbTrjjgieRbwC6Cl0",
  "q":"wLb35x7hmQWZsWJmB_vle87ihgZ19S8lBEROLIsZG4ayZVe9Hi9gDVCOBm
       UDdaDYVTSNx_8Fyw1YYa9XGrGnDew00J28cRUoeBB_jKI1oma0Orv1T9aX
       IWxKwd4gvxFImOWr3QRL9KEBRzk2RatUBnmDZJTIAfwTs0g68UZHvtc",
  "dp":"ZK-YwE7diUh0qR1tR7w8WHtolDx3MZ_OTowiFvgfeQ3SiresXjm9gZ5KL
       hMXvo-uz-KUJWDxS5pFQ_M0evdo1dKiRTjVw_x4NyqyXPM5nULPkcpU827
       rnpZzAJKpdhWAgqrXGKAECQH0Xt4taznjnd_zVpAmZZq60WPMBMfKcuE",
  "dq":"Dq0gfgJ1DdFGXiLvQEZnuKEN0UUmsJBxkjydc3j4ZYdBiMRAy86x0vHCj
       ywcMlYYg4yoC4YZa9hNVcsjqA3FeiL19rk8g6Qn29Tt0cj8qqyFpz9vNDB
       UfCAiJVeESOjJDZPYHdHY8v1b-o-Z2X5tvLx-TCekf7oxyeKDUqKWjis",
  "qi":"VIMpMYbPf47dT1w_zDUXfPimsSegnMOA1zTaX7aGk_8urY6R8-ZW1FxU7
       AlWAyLWybqq6t16VFd7hQd0y6flUK4SlOydB61gwanOsXGOAOv82cHq0E3
       eL4HrtZkUuKvnPrMnsUUFlfUdybVzxyjz9JF_XyaY14ardLSjf4L_FNY"
 }

我试过了jwk-to-pem:

/sf/answers/2519698331/

-----BEGIN RSA PUBLIC KEY-----
MIIBCgKCAQEAoahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E+BVvxkeDNjbC4
he8rUWcJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S
psk/ZkoFnilakGygTwpZ3uesH+PFABNIUYpOiN15dsQRkgr0vEhxN92i2asbOenS
ZeyaxziK72UwxrrKoExv6kc5twXTq4h+QChLOln0/mtUZwfsRaMStPs6mS6Xrgxn
xbWhojf663tuEQueGC+FCMfra36C9knDFGzKsNa7LZK2djYgyD3JR/MB/4NUJW/T
qOQtwHYbxevoJArm+L5StowjzGy+/bq6GwIDAQAB
-----END RSA PUBLIC KEY-----

还必须用"PUBLIC KEY"替换"RSA PUBLIC KEY".

该命令openssl rsa -inform PEM -pubin给出:

unable to load Public Key
139911798556312:error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag:tasn_dec.c:1197:
139911798556312:error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error:tasn_dec.c:374:Type=X509_ALGOR
139911798556312:error:0D08303A:asn1 encoding routines:ASN1_TEMPLATE_NOEXP_D2I:nested asn1 error:tasn_dec.c:697:Field=algor, Type=X509_PUBKEY
139911798556312:error:0906700D:PEM routines:PEM_ASN1_read_bio:ASN1 lib:pem_oth.c:83:

如何获得可用的密钥？

Answer 1

因此，您发布的密钥是公钥和公共指数的简单 asn 序列。它看起来像这样：

SEQUENCE ::= {
    n Integer,
    e Integer
}

OpenSSL 不喜欢这样，因为它缺少其他一些东西，比如 ObjectIdenifier，所以 openssl 知道密钥用于什么算法。

解决这个问题的快速方法是也加入-RSAPublicKey_in选项，所以完整的命令看起来像这样：

openssl rsa -inform pem -in FILEPATH.pem -pubin -pubout -RSAPublicKey_in

并将文件头改回包含“RSA”：

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

以及页脚：

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

这也会将其输出为包含缺少的 ObjectIdentifier 的“普通”公钥格式。

注意：我不确定版本要求-RSAPublicKey_in是什么，但我使用的是 OpenSSL 1.1.0。

Answer 2

我开发了一个PHP类，该类可以将公钥/私钥从JWK转换为PEM（反之亦然）。

您将在这里找到该课程。

基本上，您必须将每个组件从Base64UrlSafe解码为二进制字符串，并根据RFC3447中描述的ASN.1结构将它们组合在一起。

不过，我建议您使用专用的库/工具来简化工作。使用我的PHP库，您的代码将如下所示：

use  Jose\KeyConverter\RSAKey;
$key = new RSAKey([
    "kty" => "RSA",
    "n"   => "oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUWcJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3Spsk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2asbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMStPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2djYgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw",
    "e"   => "AQAB",
    "d"   => "kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5NWV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD93Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghkqDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vlt3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSndVTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ",
    "p"   => "1r52Xk46c-LsfB5P442p7atdPUrxQSy4mti_tZI3Mgf2EuFVbUoDBvaRQ-SWxkbkmoEzL7JXroSBjSrK3YIQgYdMgyAEPTPjXv_hI2_1eTSPVZfzL0lffNn03IXqWF5MDFuoUYE0hzb2vhrlN_rKrbfDIwUbTrjjgieRbwC6Cl0",
    "q"   => "wLb35x7hmQWZsWJmB_vle87ihgZ19S8lBEROLIsZG4ayZVe9Hi9gDVCOBmUDdaDYVTSNx_8Fyw1YYa9XGrGnDew00J28cRUoeBB_jKI1oma0Orv1T9aXIWxKwd4gvxFImOWr3QRL9KEBRzk2RatUBnmDZJTIAfwTs0g68UZHvtc",
    "dp"  => "ZK-YwE7diUh0qR1tR7w8WHtolDx3MZ_OTowiFvgfeQ3SiresXjm9gZ5KLhMXvo-uz-KUJWDxS5pFQ_M0evdo1dKiRTjVw_x4NyqyXPM5nULPkcpU827rnpZzAJKpdhWAgqrXGKAECQH0Xt4taznjnd_zVpAmZZq60WPMBMfKcuE",
    "dq"  => "Dq0gfgJ1DdFGXiLvQEZnuKEN0UUmsJBxkjydc3j4ZYdBiMRAy86x0vHCjywcMlYYg4yoC4YZa9hNVcsjqA3FeiL19rk8g6Qn29Tt0cj8qqyFpz9vNDBUfCAiJVeESOjJDZPYHdHY8v1b-o-Z2X5tvLx-TCekf7oxyeKDUqKWjis",
    "qi"  => "VIMpMYbPf47dT1w_zDUXfPimsSegnMOA1zTaX7aGk_8urY6R8-ZW1FxU7AlWAyLWybqq6t16VFd7hQd0y6flUK4SlOydB61gwanOsXGOAOv82cHq0E3eL4HrtZkUuKvnPrMnsUUFlfUdybVzxyjz9JF_XyaY14ardLSjf4L_FNY",
]);
$pem = $key->toPEM();

Answer 3

我编写了一个名为lokey的命令行工具来帮助进行像这样的密钥转换。

使用curl、grep、 和tr来获取问题中的密钥，我们可以使用以下命令将 JWK 格式的私钥转换为 PEM 格式的私钥：

$ curl -s https://tools.ietf.org/rfc/rfc7516.txt | grep '"n":"oahUI' -B1 -A28 | tr -d '[:space:]' | lokey to pem

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

lokey 还有一个fetch可用于从 OpenID 端点获取 JWK 密钥的命令：

$ lokey fetch jwk example.okta.com
$ lokey fetch jwk login.salesforce.com
$ lokey fetch jwk accounts.google.com

然后，您可以再次将此输出通过管道传输lokey以获取 PEM：

$ lokey fetch jwk example.okta.com | lokey to pem

Answer 4

一些将 JWK 转换为 PEM 的 python 代码

import jwt
from cryptography.hazmat.primitives import serialization

def GetClaim(webtoken):
    webkey = 'insert jwk here'
    public_key = jwt.algorithms.RSAAlgorithm.from_jwk(webkey)
    pubk_bytes = public_key.public_bytes(encoding=serialization.Encoding.PEM,format=serialization.PublicFormat.SubjectPublicKeyInfo)
    claim = jwt.decode(webtoken, pubk_bytes, algorithms=['RS256'])
    return claim