Re: [openssl-users] base64 decode in C
Hi, My problem is if the string that I want to decode start with null terminated char (as in a SSH pubkey), the base64_decode does not return anything at all. The encoded string itself does not have null terminated chars but rather the decoded result. The buffer being returned is empty. How to overcome this ? Also my C is relatively rusty, it would be great help if someone could look look at my code and suggest what I'm doing wrong. Also, I tried to use the EVP_DecodeBlock function with same result. It decodes everything except the SSH pubkey. Thanks. --Prashant On 18 March 2015 at 22:56, Scott Neugroschl scot...@xypro.com wrote: I believe the SSH pubkey is binary data, not ASCII, so strlen() will not work on it if it has embedded NUL chars. As Dave Thompson suggested, instead of strlen(), use the length returned from BIO_read. *From:* openssl-users [mailto:openssl-users-boun...@openssl.org] *On Behalf Of *Prashant Bapat *Sent:* Wednesday, March 18, 2015 8:08 AM *To:* openssl-users *Subject:* Re: [openssl-users] base64 decode in C Hi Dave and Walter, Thanks for our reply. I'm not doing anything different for the ssh pubkey. I'm able to decode it using the openssl enc -base64 -d -A command. But not using the C program. Attaching my entire code here. After getting the base64 decoded I'm calculating the MD5 sum and printing it. This works for a regular string but not for SSH pubkey. Thanks again. --Prashant On 18 March 2015 at 18:04, Walter H. walte...@mathemainzel.info wrote: Hi, before calling this function, remove any whitespace; Walter ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
Re: [openssl-users] base64 decode in C
Hey I got this. Sorry I was confused with the length. BIO_read returns the length which I was able to use to get the MD5. Problem solved!!! Many thanks. --Pashant On 19 March 2015 at 14:24, Prashant Bapat prash...@apigee.com wrote: Hi, My problem is if the string that I want to decode start with null terminated char (as in a SSH pubkey), the base64_decode does not return anything at all. The encoded string itself does not have null terminated chars but rather the decoded result. The buffer being returned is empty. How to overcome this ? Also my C is relatively rusty, it would be great help if someone could look look at my code and suggest what I'm doing wrong. Also, I tried to use the EVP_DecodeBlock function with same result. It decodes everything except the SSH pubkey. Thanks. --Prashant On 18 March 2015 at 22:56, Scott Neugroschl scot...@xypro.com wrote: I believe the SSH pubkey is binary data, not ASCII, so strlen() will not work on it if it has embedded NUL chars. As Dave Thompson suggested, instead of strlen(), use the length returned from BIO_read. *From:* openssl-users [mailto:openssl-users-boun...@openssl.org] *On Behalf Of *Prashant Bapat *Sent:* Wednesday, March 18, 2015 8:08 AM *To:* openssl-users *Subject:* Re: [openssl-users] base64 decode in C Hi Dave and Walter, Thanks for our reply. I'm not doing anything different for the ssh pubkey. I'm able to decode it using the openssl enc -base64 -d -A command. But not using the C program. Attaching my entire code here. After getting the base64 decoded I'm calculating the MD5 sum and printing it. This works for a regular string but not for SSH pubkey. Thanks again. --Prashant On 18 March 2015 at 18:04, Walter H. walte...@mathemainzel.info wrote: Hi, before calling this function, remove any whitespace; Walter ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
Re: [openssl-users] base64 decode in C
Hi, before calling this function, remove any whitespace; Walter smime.p7s Description: S/MIME Cryptographic Signature ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
Re: [openssl-users] base64 decode in C
Hi Dave and Walter,
Thanks for our reply.
I'm not doing anything different for the ssh pubkey. I'm able to decode it
using the openssl enc -base64 -d -A command. But not using the C program.
Attaching my entire code here. After getting the base64 decoded I'm
calculating the MD5 sum and printing it. This works for a regular string
but not for SSH pubkey.
Thanks again.
--Prashant
On 18 March 2015 at 18:04, Walter H. walte...@mathemainzel.info wrote:
Hi,
before calling this function,
remove any whitespace;
Walter
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#include openssl/md5.h
#include openssl/sha.h
#include openssl/hmac.h
#include openssl/evp.h
#include openssl/bio.h
#include openssl/buffer.h
#include string.h
#include stdio.h
char *b64_decode(unsigned char *input, int length);
char* md5_digest(char *string);
int main()
{
char *str = B3NzaC1yc2EDAQABAAABAQC/KdcFv09+f+tJK9IZ8I+L0zG7dUINClI5v8FlHJsBPSM3DDO2DpwIg/KqZKCRH9y6lEO+QAJt2DTEq/LBZcBUCdeiX1TXPFRorX+VdZigj7av/S/UHkq2EH6hfkJB3oLA5ZOZioMOAuDv1ng/DE4pRBr+KZ2oVhGjf3wa0hWi21vTZqb3s7vh+bPf6C2eUmAQJKHvFhtBK8Xx7FxN0b7igsGbk7ObwcItfMxdzkMvuiuU/UnthFVpa8wZIObFDi3MxJuf3/R+h6R1lFMvEIrU6CWRupS7Pqkm4X3qWQfhAWbdgdbD5KAk5JLA2eWIPQQA5Uay5CeH+GXz8gCa4zaz;
printf(Base64 decoded string is : %s\n, b64_decode(str, strlen(str))); // This should print binary for a ssh key.
printf(MD5 Sum of the decoded string is : %s\n, md5_digest(b64_decode(str, strlen(str;
return 0;
}
char *b64_decode(unsigned char *input, int length)
{
BIO *b64, *bmem;
char *buffer = (char *)malloc(length);
memset(buffer, 0, length);
b64 = BIO_new(BIO_f_base64());
bmem = BIO_new_mem_buf((void*)input, length);
bmem = BIO_push(b64, bmem);
BIO_set_flags(bmem, BIO_FLAGS_BASE64_NO_NL);
BIO_read(bmem, buffer, length);
BIO_free_all(bmem);
return buffer;
}
char* md5_digest(char *string)
{
int i;
unsigned char result[MD5_DIGEST_LENGTH];
// Length of MD5 signature is 32 !
char * md5_sig = (char *) malloc(33);
MD5(string, strlen(string), result);
// output
for(i = 0; i MD5_DIGEST_LENGTH; i++){
sprintf( md5_sig[i*2], %02x, result[i]);
}
return md5_sig;
}
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Re: [openssl-users] base64 decode in C
Please refer to Dave Thompson's answer, it describes your problem. On 18/03/2015 16:08, Prashant Bapat wrote: Hi Dave and Walter, Thanks for our reply. I'm not doing anything different for the ssh pubkey. I'm able to decode it using the openssl enc -base64 -d -A command. But not using the C program. Attaching my entire code here. After getting the base64 decoded I'm calculating the MD5 sum and printing it. This works for a regular string but not for SSH pubkey. Thanks again. --Prashant Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
Re: [openssl-users] base64 decode in C
I believe the SSH pubkey is binary data, not ASCII, so strlen() will not work on it if it has embedded NUL chars. As Dave Thompson suggested, instead of strlen(), use the length returned from BIO_read. From: openssl-users [mailto:openssl-users-boun...@openssl.org] On Behalf Of Prashant Bapat Sent: Wednesday, March 18, 2015 8:08 AM To: openssl-users Subject: Re: [openssl-users] base64 decode in C Hi Dave and Walter, Thanks for our reply. I'm not doing anything different for the ssh pubkey. I'm able to decode it using the openssl enc -base64 -d -A command. But not using the C program. Attaching my entire code here. After getting the base64 decoded I'm calculating the MD5 sum and printing it. This works for a regular string but not for SSH pubkey. Thanks again. --Prashant On 18 March 2015 at 18:04, Walter H. walte...@mathemainzel.infomailto:walte...@mathemainzel.info wrote: Hi, before calling this function, remove any whitespace; Walter ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
[openssl-users] base64 decode in C
Hi,
Most likely this has been answered before, please bear with me.
I'm trying to use the base64 decode function in C. Below is the function.
char *b64_decode(unsigned char *input, int length)
{
BIO *b64, *bmem;
char *buffer = (char *)malloc(length);
memset(buffer, 0, length);
b64 = BIO_new(BIO_f_base64());
bmem = BIO_new_mem_buf((void*)input, length);
bmem = BIO_push(b64, bmem);
BIO_set_flags(bmem, BIO_FLAGS_BASE64_NO_NL);
BIO_read(bmem, buffer, length);
BIO_free_all(bmem);
return buffer;
}
This works well for simple b64 encoded strings like hello world! etc. But
when I want to b64 decode the contents of a SSH public key, it fails.
Returns nothing.
What I'm trying to get to is the SSH public key fingerprint which is the
MD5 hash of the base64 decoded part of the public key.
This decodes fine.
dGhpcyBpcyBhd2Vzb21lCg== : this is awesome
This does not.
B3NzaC1yc2EDAQABAAABAQC/KdcFv09+f+tJK9IZ8I+L0zG7dUINClI5v8FlHJsBPSM3DDO2DpwIg/KqZKCRH9y6lEO+QAJt2DTEq/LBZcBUCdeiX1TXPFRorX+VdZigj7av/S/UHkq2EH6hfkJB3oLA5ZOZioMOAuDv1ng/DE4pRBr+KZ2oVhGjf3wa0hWi21vTZqb3s7vh+bPf6C2eUmAQJKHvFhtBK8Xx7FxN0b7igsGbk7ObwcItfMxdzkMvuiuU/UnthFVpa8wZIObFDi3MxJuf3/R+h6R1lFMvEIrU6CWRupS7Pqkm4X3qWQfhAWbdgdbD5KAk5JLA2eWIPQQA5Uay5CeH+GXz8gCa4zaz
What I'm I doing wrong ?
Btw in the command line both decode. Using echo string | openssl enc
-base64 -d -A
Any help appreciated.
Thanks in advance.
--Prashant
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Re: [openssl-users] base64 decode in C
On 18.03.2015 16:08, Prashant Bapat wrote: printf(Base64 decoded string is : %s\n, b64_decode(str, strlen(str))); // This should print binary for a ssh key. not really, because the return of b64_decode is not a C string; and the format specfier %s expects a C string; smime.p7s Description: S/MIME Cryptographic Signature ___ openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
