Studying a source code of one of the cpu miners I found this piece of code:
work->data = 0x80000000;
Well, I asked the coded about it and his answer was:
"Those values are part of standard SHA-2 padding"
Googling "sha 2 padding" didn't help. Can you tell me what is this for?
I thought that md5/sha256 functions simply take data and return hash.
I don't understand the "padding" concept.
I'm building a minimal-dependancy crypto library, working on a keccak implementation based on this specification document.
I'm confused about following
aspect of the
t computation described in the paper among the group of calculations on page 8.
Is there a simple, pythonic way to calculate
t, or do I need to learn about matrix-logarithms?
This question already has an answer here:
I see that doing this on a Debian Linux:
$ echo "a" |sha256sum
87428fc522803d31065e7bce3cf03fe475096631e5e07bbd7a0fde60c4cf25c7 whereas doing this with Python 2.7 on Windows:
import hashlibprint hashlib.sha256("a").hexdigest()
Why does the string
a produce two different SHA256 hashes?
Im trying to generate sha to use facebook plugin and I tried to creat with severals tutorial but I cant do it, letme put the error:
C:\Program Files\Java\jdk-9.0.1\bin>keytool -list -v -keystore C:\Users\Gaston\.android\debug.keystore -alias androiddebugkey -storepass android -keypass androidNombre de Alias: androiddebugkeyFecha de Creación: 23 feb. 2016Tipo de Entrada: PrivateKeyEntryLongitud de la Cadena de Certificado: 1Certificado:error de herramienta de claves: java.util.IllegalFormatConversionException: d != java.lang.Stringjava.util.IllegalFormatConversionException: d != java.lang.String at java.base/java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4331) at java.base/java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2846) at java.base/java.util.Formatter$FormatSpecifier.print(Formatter.java:2800) at java.base/java.util.Formatter.format(Formatter.java:2581) at java.base/java.util.Formatter.format(Formatter.java:2517) at java.base/java.lang.String.format(String.java:2747) at java.base/sun.security.tools.keytool.Main.withWeak(Main.java:3151) at java.base/sun.security.tools.keytool.Main.printX509Cert(Main.java:3182) at java.base/sun.security.tools.keytool.Main.doPrintEntry(Main.java:1995) at java.base/sun.security.tools.keytool.Main.doCommands(Main.java:1212) at java.base/sun.security.tools.keytool.Main.run(Main.java:397) at java.base/sun.security.tools.keytool.Main.main(Main.java:390)
I work on a couple sites hosted on a far-away government Windows Server 2012, and Firefox will not connect to them. It says:
"Secure Connection Failed - The page you are trying to view cannot be shown because the authenticity of the received data could not be verified."
They restrict the server to TLS 1.2 protocol only, and I'm told none of the default ciphers are disabled explicitly, but SHA hash is disabled, and Diffie-Hellman key exchange is disabled, and all but Triple DES and AES ciphers disabled. This must be why the sites are limited to six cipher suites, according to ssllabs, none of which coincide the ones used by Firefox.
I saw other discussion on a different forum where the same problem was overcome by enabling SHA hash, which I assume would enable TLS_DHE_RSA_WITH_AES_256_CBC_SHA and TLS_RSA_WITH_AES_256_CBC_SHA, both of which work on Firefox. But I did not find much more.
I'm thinking the Diffie-Hellman key exchange might enable TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, which also works on Firefox.
So far no one has complained, but this is going to be notices as more of our servers comply with new rules. Anyone else run into this and have any suggestions or thoughts, on what is the best path? Or do we just discourage Firefox? Thanks!